' ,, \' 'I University of Texas Bulletin No. 1856: October 5, 1918 ' . The Weno and Pawpaw Formations of the Texas Comanchean BY W. S. Adkins '·, On A New Ammonite Fauna of the Lower Turonian of Mexico BY Emil Bose r· , I ' . I I Bureau of Economic Geology and TechnoJogy Division of Economic Geology J. A. Udden, Director of the Bureau and Head of the Division ' , PUBLISHED BY THE UNIVERSITY OF TEXAS AUSTIN ' , , ' . . \ I I Publications of the University of Texas · Publications Committee: FREDERIC DUNCALF C. T. GRAY KILLIS CAMPBELL ' E. J. MATHEWS D. B. CASTEEL C. E. ROWE F. W. GRAFF A. E. TROMBLY The University publishes bulletins six times amonth, so numbered that the first two digits of the number .~how the year of issue, the last two the position in.the yearly series. (For example, No. 1701 is the first bulletin of the year 1917.) These comprise the official publications of the University, publications on humanistic and scientific sub­jects, bulletins prepared by the Bureau of Extension and by the ·Bureau 0f Government Research and Reference, and ( ' other bulletins of general educational interest. With the exception of spE!cial numbers, any bulfotin will be sent to a citizen · of' Texas free on request. All communications about University publications should be addressed to Uni­versity Publications, University of Texas, Austin. 51520-980-4818-2m University of Texas Bulletin No. 1856: October 5, 1918 The Weno and Pawpaw Formations of the Texas Comanchean BY W. S. Adkins On A New Ammonite Fauna of the Lower Turonian of Mexico BY Emil Bose Bureau of Economic Geology and Technology Division of Economic Geology J. A. Udden; Director of the Bureau and Head of the Division PUBLISHED BY THE UNIV.hRSITY SIX TIMES A MONTH, AND ENTERED AS SECOND-CLASS MATTER AT THE POSTOFFICE AT AUSTIN, TEXAS, UNDER THE ACT OF AUGUST 24, 2 The bene&ta of education and of useful lmowledse, senerally diffused thro-.gh a community, are eHential to the preserYation of a free go•ern­ment. Culti•atecl mind is the l'uardian l'enius of democracy••.•• It is the only dictator that freemen acknowl­edse and the only security that free­men desint. Mirabeau B. Lamar The Weno and Pawpaw Formations of the Texas Comanchean llY W. S. Adkins CONTENTS INTRODUCTION. 9 STRATIGRAPHY. . 13 Rocks underlying the Weno and Pawpaw Formations. . . . . . . . . . . . . . . . . . . 13 Pre-Comanchean. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lH Comanchean. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Thickness changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Lithological changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Weno and Pawpaw Formations......... . ............................ 25 Thickness changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 North-South changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2o East-West changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Lithological changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Pawpaw Formation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Weno Formation. . ........ , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Stratigraphic Correlation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ·40 North Central Texas and Southern Oklahoma. . . . . . . . . . . . . . . . . . . . . 40 South Central Texas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 West Texas and Mexico. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Europe and North Africa. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 PALEONTOLOGY. . . ....................·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 The Weno Fauna. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 The Pawpaw Fauna. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Comparison of Pyrite Faunae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Texas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Kiamitia Clay Fauna. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . 54 Duck Creek Marl Fauna. . ...... ; . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Denton Clay Fauna. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Grayson Fauna. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Del Rio Clay Fauna. . ................... ; . . . . . . . . . . . . . . . . . 58 Summary of Pyrit-e Faunae. . . ....................... ,. . . . . . . 60 Europe and Africa. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 DESCRIPTIONS OF SPECIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 CEPHALOPODA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Nautilus texanus Shumard................... ... ...·. . . . . . . . . . . . . 68 Nautilus sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Hamites tenawa Adkins and Winton............................. 69 Hamites sp. aff. armatus Sowerby. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Ancycloceras bendirei n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Hamulina wortbensis n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Baculites comancbensis n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4 Turrilites bosquensis n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Turrilites wortbensis Adkins and Winton. . . . . . . . . . . . . . . . . . . . . . . . . 78 Turrilite~ sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Scapbites billi Adkins and Winton. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 University of Texas Bulletin 8'! Engonoceraa aerpentinum (Cragin) ............... · · · · · · · · · · · · · · 85 Engonoceraa sp. . ............................... · · · · · · · ·. · · · · 85 Flickia boeaei n. sp. . .............. , .......... · · · · · · · · · · · · · · · · · 8'7 Flickia ( ?) boaquenais n. sp. . ...................... · · · · · · · · · · · · 89 Schloenbachia wenoenaia ·n. sp. . ............... · · · · · · · · · · · · · · · · 90 Schloenbachia wintoni n. sp. . .................... · . · · · · · · · · · · · · 91 Mortoniceraa worthenae n. sp. . ................... · · · · · · · · · · · · · · 93 Acanthoceraa worthenae n. sp. . .................... · · · · · · · · · · · · ASTEROIDEA..................................................... · · 95 Pentagonaater texenaia Adkins and Wbton ..................... · ; 95 Metopaater hortenaae Adkins and Winton ...................... · · · 97 Comptonia wintoni n. sp. . ................................ · · . · · 97 P'entaceros americanua n. sp....................... ·........... · · 99 ECHINOIDEA. . .,. . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Leiocidaria sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Goniopygua sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Pedinopaia aymmetrica (Cragin) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 ·Peltaatea sp. . . ..........·.................................... 102 Salenia sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Cyphoao1111a volanum Cragin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Holectypua limitia Bose. . ................·. . . . . . . . . . . . . . . . . . . . . . 1O~ Holaater sp. aff. simplex ·Shumard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Epiaater wenoenaia n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Epiaater aguilerae Bose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10» Epiaater aubobeaua n. sp.......•.............................. 110 EnalLaater wenoenaia n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 Enallaater bravoenaia Bose..................................... 114 Enallaater sp. aff. texanua (Roemer) ........................... ~ . 11'1 Hemiaater calvini Clark. . . ............................... ; . . . . . 11 i Hemiaater riovistae n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 PELECYPODA....................................................... 118 Nucula nokonia n. sp. . . ..............·. . . . . . . . . . . . . . . . . . . . . . . . . 118 Nucula wenoenaia n. i:;p. . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 Arca waahitiaenaia n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 Gervilliopaia inv-aginata (White) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 Oatrea carinata ? Lamarck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12~ Oatrea ap. aff. diluviana Linnaeus ............................ ·. . . 122 Oatrea (Alectryoniia) quadriplicata Shumard. . . . . . . . . . . . . . . . . . . . . . 12~ Exogyra sp. aff. arietina Roemer ................................ 123 Pecten inconapicuua Cragin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12~ Pecten georgetc>wnenaia Kniker. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Venericardia wenoenaia n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Protocardia sp. aff. multiatriata (Shumard) ....................... 126 Corbula wenoenaia n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 Corbula baainiformis n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 CorbuLa littoralia n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Cyprimeria washitaenaia n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 Remondia ? acuminata (Cragin) ................................ 136 Weno and Pawpaw Forrnations f"' ' GASTROPODA. . .................................. , . . . . . . . . . . • . . . . . . 137 Amberleya graysonensis n. sp.................................... 137 Trochus laticonicus n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 Helicocryptus mexic,anus Booo. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 Nerita sp. . . ............................ : . . . . . . . . . . . . . . . . . . . . 139 Neritina sp. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . 139 Ancbura mudgeana White. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 Natica sp....................................... , . . . . . . . . . . . . 140 Lunatia sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 Globiconcba sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 Turritella graysonensis n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 TurritelLa wortbensis n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 Cinuli:a washit1aensis n. sp. . ............................. , . . . . . . 143 PROTOZOA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 Nodosaria texana Conrad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 BIBLIOGRAPHJ'.-. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14~ PLATES 1-11.•..................................................149-170 8 University of Texas Bulletin LIST OF ILLUSTRATIONS FIGURES Figure 1. Map of Texas a!'ld part of Oklahoma showing outcrops of the Weno and Pawpaw formations, and the lithological facies of the Pawpaw formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Fi~ure 2. Ancycloceraa bendirei n. sp., suture of the typ·e individual, camera lucida drawing, x 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Figure 3. Hamulina worthenae n. sp., sutures of type individual, camera lucida drawing, x 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Figure 4. Baculitea com.anchenais n. sp., sutures of type individual, camera lucida drawing, x 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Figure 5. Turrilites boaquensis n. sp., sutures, type individual, camera lucida drawing, x 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 Figure 6. Scaphitea hilli Adkins a!'ld Winton, type individual, diagrammatic restoration showing orientation and sutures, camera lucida drawing, x 12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Figure 7. Scaphitea hilli Adkins and Winton, young individual, showing the last five sutures, camera lucida drawing, x 10 . . . . . . . . . . . . 8~ Figure 8. Scaphites hilli Adkins and Wi!'lton, external and internal. suture, camera lucida drawing, x 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Figure 9. Flickia boeaei n. sp., type individual, sutures, camera lucida draw­ing, x 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Figure 10. Flickia bosquensia n. sp., diagrammatic proj·ection of sutures of type individual, camera lucida drawing, x 5 . . . . . . . . . . . . . . . . . . 88 Figure 11. Schloenbachia wintoni n. sp., type individual, last sttture, camera lucida drawing, x 5. Keel regio!'l slightly distorted in type individual. . . .........................................·. 91 Figure 12. Mortoniceras worthense n. sp., suture of individual, Plat•e 1; figure 6, · camera lucida drawing, x 10 ......... , . . . . . . . . . . . . . . . . . 93 Figure 13. Acanthoceraa worthenae n. sp., suture, camera ludda drawing, x 8 94 PLATES Plates 1-11. Fossils of the Weno a!ld Pawpaw formations ..............149-170 THE WENO AND PAWPAW FORMATIONS OF THE TEXAS COMANCHEAN1 By W. S. ADKINS INTRODUCTION The Weno and Pawpaw f\. rmations are two thin formations lying near the top of the Comanchean series of strata, and are most typically developed in the region between the Red and the Brazos rivers. The importance of these formations, especially the Pawpaw, is much greater than their thick­ness would seem to indicate. The Pawpaw is a formation of small thick­ness, sharply limited lithologically both above and below, and contains a remarkable series of small pyritic fossils which are so sharply charar­ . terized and so distinctive in appearance, even in minute fragments such as are encountered in drilling, that this formation should be recognized in wells lying to the east of its outcrop and should furnish at least one certain and dependable stratigraphic level in the Comanchean. In the hope that the formation may have this value, its fauna has been described in some detail and the lateral variations in its lithological character indicated.2 The same statements hold to a lesser extent for the We no formation. The stratigraphic position of these two formations in the Comanchean serie·s and their equivalents in the Central Texas section are given in the fol­lowing table. The Weno and Pawpaw formations are visible over a small areal extent, their outcrops aggregating somewhat more than 100 square miles, mainly in a narrow strip in Johnson, Tarrant, Denton, Cooke and Grayson Coun­ties, Texas, and Love, Marshall, Bryan and Choctaw Counties, Oklahoma. In addition they have stratigraphic equivalents in Central and Western Texas and in Mexico, that will be discussed later. Their north-south dis­tribution in Texas is between Lat. 32°N. and 34°N.; and their east-west distribution is practically unknown. In ~klahoma their east-west distri­bution is between Long. 95°15' and 97° ; and their north-south distribution is unknown. The total length of their outcrop north of the Brazos River 1Manuscript accepted June 15, 1920, published November, 1920. 21t is hoped that operators and others having well samples suspected of being Upper Comanchean will submi~ them for examination to the Bureau of Economic Geology at Austin. s1 wish to express my indebtedness to Professor W. M. Winton, with whom the preliminary work on these and other Comanchean formations was done jointly. The results of these studies will appear in forthcoming papers by both authors. University of Texas Bulletin CORRELATION TABLE OF THE COMANCHEAN FORMATIONS OF CENTRAL TEXAS1 COMANCHEAN - is about 110 miles in Texas and 100 miles in Oklahoma. The outcrop is S­shaped, and north and west of its limits in North Central Texas the forma­tions are e1foded away; while east and south of the outcrop, the Weno­Pawpaw rock sheet continues underground for an .unknown distance, being buried beneath the more recent Comanchean and Cretaceous strata. This concealed extension of these formations still awaits exploration by means of detailed well logs and the examination of sanwles f roni drillings. The formations ·show distinct north-south changes along their outcrops and equally distinct east-west changes. As a whole, they thicken moderately from the Brazos river (near Blum) north to the Red River (north of Gainesville), and thence eastward down the Red River valley through Den­ 1See also: Bose, University of Texas Bulletin, 1902, p. 16, fig. 1. 2The Comanchean sea was transgressive northwards over much of Central Texas, and the Basement sand is not a single formation, but at different places is the time equivalent of various off-shore formations. Weno and Pawpaw Formations ,,,,...,...,. ..,,.., ~.,,..,. " : .. '~ .. ..........., ., .... ~·---" J ~ •• I• •• "O• Fig. 1. Map of Texas and part of Oklahoma, showing outcrops of the W eno and Pawpaw formations and the lithological facies of the Pawpaw formation. SI-San.dstone and Ironstone; Cl-Clay; M-Marl; LS-Limestone. Universit11 of Texas Bulletin ison and Bennington they thicken rapidly; so that by inference the main thickening is ENE. and the lines of equal thickness run about 60° E. of N. Southward from the Red River in Cooke County the Weno and Pawpaw formations thin gradually to at least the Colorado River where they are probably represented by strata lying near the top of the Georgetown lime­stone. The two formations behave very differently over the area men­tioned. The Weno formation, south of the change of direction of its out­crop in Cooke County decreases slightly in thickness, from about 75 feet near Gainesville to 65 feet near Fort Worth, 60 near Rio vista, 40 near Waco, and 20 ( ?) near Georgetown. The Pawpaw clay on the other hand, thins more rapidly from the Red River southward. Near Cedar Mills, Cooke County it is 60 feet thick, in Denton County 40 feet, at the north border of Tarrant County 27 feet, on Sycamore Creek near Fort Worth 24 feet, at the south border of Tarrant County 12 feet, at Riovista 5 feet, at UUum 3 feet, and near "Vaco about 2 feet thick. This thinning is a part of the general thinning southwards of the softer formations of the North Texas Washita, which south of the Brazos are represented in the George­town limestone, as is observable in the Kiamitia marl, Duck Creek marl, Denton marl, Pawpaw clay and Grayson marl. The alternate harder for­mations, the Duck Creek limestone, Fort Worth limestone, W eno limestone, Mainstreet limestone, ·. undergo proportionately less thinning southwards and hence contribute relatively larger components to the Georgetown lime­stone. There are equally distinct differences of lithology and facies, which are presented later. The present paper is only an introduction to the large and interesting Weno and Pawpaw faunae, the majority of whose species are still unde­scribed. Much collecting and further study is required before any attempt can be made towards a monographic treatment of these fossils. It ~ill be noted that the limits set in this paper coincide with the boundaries of hori­zons 25 to 33 inclusive, of Adkins and Winton's preliminary .section of the North Texas Washita d.ivision.1 1 Adkins and Winton, Paleontological Correlation of the Fredericksburg and Washita Formations in North Texas. Univ. Texas Bull. 1945, 1920. STRATIGRAPHY The stratigraphy of the Weno and Pawpaw formations involves the re­ gional stratigraphy of the Comanchean area north of the Brazos River, and accordingly, certain lithological and structural features of this region will be described. In almost the whole region in question, along the line of outcrop of these two formations between the Brazos and the Red Rivers, the Comanchean sediments are deposited over a large geosyncline whose axis is transverse to the direction of the Comanchean outcrops-i. e., roughly northwest­ southeast--and whose bulk was largely filled in by pre-Comanchean depos­ its. However, there is a feeble surface reflection of this buried structure, which influences the thickness and lithologic.characters of all Comanchean deposits, including the Weno and Pawpaw formations. The north edge of this deep trough is near the Red River and the south edge is south of the Brazos ; the north slope is steep and the south slope more gpnt,le. This de­ pression, in which the Fort Worth region is located will be called the Fort Worth geosyncline. ROCKS UNDERLYING THE WENO AND PAWPAW FORMATIONS PRE-COMANCHEAN lts extent may be indicated by the meager data available on the under­ ground position of the Ellenburger limestone. At Muenster, Cooke County, it was reached at a depth of about 1800 feet, or 1050 feet below sea level. At Myra, Cooke County, the Ellenburger was reached at a depth of 1640 feet below the surface or about -900 feet (sea level) .1 In the Polytechnic (Byrens-Burchell No. 1) well near Fort Worth, the Ellenburger if present lies below -3950 feet, at which level the Bend has probably not been reached. The difference in elevations of the last two subsurface points is 3050 feet which represents the minimum change of elevation of the first Eilenburger reached between Myra and Fort Worth, in case the Ellenburger is present •at the latter place. Coincidentally the thickness of Pennsylvanian deposits is not more than 600 feet at Myra, but has increased to at least 3600 feet at Fort Worth. Other wells in Tarrant and nearby counties have penetrated similar Pennsylvanian :rp.aterial. Farther south there is doubt that the Ellenburger is present. In the Hillsboro well the pre-Cambrian rocks were said to be reached at a depth 1Matteson, Econ. Geol., XIV, No. 2, p. 1919. University of Texas Bulletin of 2100 feet, apparently without intervening Ellenburger, and at Waco th.e pre-Cambrian is present at about 2500 feet. However, at points still farther south and southwest, as at Gatesville and Leander, the Ellenburger is present but thin, and overlies pre-Cambrian shales or slate-graywacke which near Leander are stated to be identical in appearance with the Virginia shales and to be of upper Huronian age.1 At Georgetown, Leon Springs and Camp Bullis, 2 the Trinity directly overlies the pre-Cambrian schists ;3 the depths of the contact are respectively 1100 feet, 1015 feet, and 1790 feet. The depression which is triangular shaped and narrower to the north­west, is flank.ed to the north, at least in Cooke County, by a structurally high area of Ellenburger at -900 feet, and a thin Pennsylvanian; and to the west by the structurally high Bend Arch in which the -3000 and -3500 Ellenburger contours have a trend east and south.4 Whether this Ellenbur­ger depression opens to the southeast or to the northwest is not known to me. It was, however, invaded by the Pennsylvanian seas which deposited in its central part at least 3600 feet of sediments, and left a surface which was more largely levelled than the original floor. Upon this surface the Comanchean sea transgressed from the southeast, depositing sediments which still show a feeble reflection of the underlying geosyncline. COMANCHEAN THICKNESS CHANGES Any pre-Comanchean ridges and valleys over which the Comanchean seas spread would be indicated by deposition which is thicker in the valleys and thinner over the crests. If therefore we identified a regional thinning of the beds in two directions from a given location, this might be _attributed to deposition on two sides of an existing valley in the ocean bottom, whether originally this valley was erosional or synclinal. This lensing is evident in the Comanchean formations, and particularly in the lower ones ( Glenrose, Paluxy). For example the Glenrose fills in much of the depression by lens­ing; at Decatur it is about 35 feet thick but at Fort Worth about 475 feet, 1By Professor. A. W. Johnston, oral communication. 2Sellards: The Geology and Mineral Resources of Bexar County, Univ. Texas BulJ. 1932, pp. 19-20. 3These facts were discovered by Dr. J. A. Udden, who has kindly permitted their use here. 4Sellards: On the Underground Position of the Ellenburger Formation in North Central Texas, Univ. Texas Bull. 1849, 1920. Weno and Pawpaw Formations and is increasing southeastward at the rate of about 8 feet per mile. (Hill). Likewise the Paluxy entirely disappears to the south. There are in addition two complicating circumstances, which affect the thickness and lithology, general regional thickening and depositional facies. The Fredericksburg division increases steadily in thickness from the Red River to beyond the Rio Grande. Its marl and marly limestone facies persist at most levels to APPROXIMATE THICKNESS OF THE COMANCHEAN FORMATIONS OF NORTH TEXAS, IN FEET I'll CIS >. ::s ,... 0 c:Q 0 . 8 ;:..'.; +> s:::::s 0 0 s::: r/l 0 :>. Cl!,... C!:I :>. +>i::::s 0 0 Cl) ..!<: 0 0 0 >. +> s:::::s 0 0 i:: 0 +>s::: Cl) i::l ~ s:::::s 0 0 +"s::: Cl!,...,... CIS 8 >. ..... s:::::s 0 0 ,... Cl) ..!<:,... Cl! Pot :>. +>s:::::s 8 s::: 0 r/l 0 i::..c: '""> I>. +> s:::::s 0 0-­..... tt: Woodbine ......... 200t 500 400:1: 400­ 325 .......100-300 lOO:j: Buda ............. ....... Grayson .......... 50 50t 60 82 80 ....... 100 Mainstreet ........ 5 10-15 40 50 50 ....... 50 35:1: Pawpaw .......... 56 50 45 27-40 12-27 ....... 9-18 5 Weno ....... ..... 114 125 110 70-100 62 ....... 40 25 Denton ........... 25 25 25 25 25 ....... 20-25 5 Fort Worth ....... 30 30 30 30 . 32 30 25-27 25 Duck Creek marl ... Duck Creek limestone 40 100 60 130 30:j: 50:j: 30:j: 50:j: 22 45 20~40 20 40 50 Kiamitia .......... 130 61 40 30-40 27-31 30 18 19 Goodland ......... 16 12-20 19 117 ....... Edwards .......... ..... ....... 20 35 40 Comanche Peak .... ..... ....... 120 105 150 Walnut ........... 8 (5) . 5-15 125-150 150 100 150 Paluxy ........... 150 150 90 150 Glenrose .......... ? 470 100-300 400 -500 Basement Sand .... 250 250 200:j: 200? 150:1: 150:j: 150 WASHITA (e x c I u­s iv e Woodbine .. 550:j: 541:j: 430 394 374 120 338 164t F R E D E R I C K S­BURG ......... 25? 50 25? 242 290 330 350 TRINITY ......... ? 200? 770:j: 650 COMANCHEAN ... 825 841 655 1386 :j:Approximate thickness. Univer$ity of Texas Bulletin the region between the Brazos and the Colorado Rivers. South and west of this region the Rudistid facies invades the Fredericksburg division, begin­ning with the level representing the top of the Edwards limestone (see page 24). The Rudistid facies is characterized by considerable thickness of indurated massive limestone, so that southward as this facies vertically invades the stratigraphic column the invaded formations thicken, Rough estimates of the thickness of this division are: Red River (Denison, 50 feet; Goodland, Oklahoma, 25 feet); Trinity River (Fort Worth), 242 feet; Colorado River (Austin), 350 feet. And for the Washita division: Den­ison, 541 feet; Fort Worth, 37 4 feet; Austin, 220 feet. In the following table of approximate thicknesses it should be noted that the basal Comanchean deposits are transgressive northwards in such a manner that we do not know with certainty what part if any of the Base­ment Sands of Cooke, Grayson and Denton Counties is of Trinity age. The lowest determined Comanchean fossils in this area indicate the level of Exogyra texana and _its varieties of Walnut age. In the Duck Creek forma­tion of the table the "marl" is taken to be the portion above the Mineralized Ledge1 (Stratum 17) of the Fort Worth region, i.e., above the horizon of abundance of Scaphites worthensis. LITHOLOGICAL CHANGES The lithology of the Washita division is diverse and ea~h formation must be considered separately. However, it is generally true in North­Central Texas that the formations decrease in thickness southwards to the Bra:tos-Colorado divide south of Waco, Texas ; these changes in thick­ness and lithology may be considered as a unit, and are related to the depositional conditions in the large North-Central Texas trough already re­ferred to. Crossing the Brazos-Colorado Divide in which the thinned Penn­sylvanian and Ellenburger and pre-Cambrian floor are structurally high, there is in the Cretaceous another set of thickness changes which for cer­tain formations, notably the Buda, amount to a regional increment in thickness as far south as the turning point of the Washita outcrops in Bexar County. Westward from this point there appears a little known set of changes in thickness and lithology of these formations. In West Texas again, the northern, near-shore facies (Cerro de Muleros, Finlay Moun­tains, Kent, Sierra Blanca) passes quickly into the southern, massive limestone, in part rudistid facies (Shafter, Terlingua, Fort Stockton, Shef­field) and the Texas and Pacific Railway is approximately the boundary line between these two facies. The tr~nsition zone from the Edwards 1Winton and Adkins: The Geology of Tarrant County, Univ. Texas Bull. 1931, pp. 42-43. Weno and Pawpaw Formations limestene level passes between Fort Stockton and Sheffield and eastward to a point near Pecos, thence some distance north of Coke and Runnels coun­ties, north of the Central Mineral Region, and approximately to the north­ern border of Hood County, near Comanche Peak. Here the Edwards out­crop disappears eastward under the later formations. An extended study of the rudistid facies will be necessary to define this boundacy line pre­cisely; but it is cited here as an illustration of the type of lithological vari­ations seen within the extent of the Texas Comanchean outcrops. For the other Washita formations likewise, much field work will be necessary to map even approximately their different lithological facies; accordingly the following summary of these formations is brief and condensed. GRAYSON FORMATION Sandstone faciea: Unknown. Clay facies: Upper half of the Del Rio Clay (approximately the Gryphea mucronata zone, south of the Brazos River). The middle member of the Grayson is a clay as far north as Denton County, Texas. ­ Marl faciea: Near Bennington, Durant and Bokchito, Oklahoma, Denison, Fink, Gainesville, Denton, Fort Worth, and Burleson, Texas. This is the pre­vailing facies along the outcrop. The eastermost exposure in Central Texas is east.of Roanoke, Texas, where the few, insignificant limy seams seen in the Fort Worth region are represented by eleven conspicuous limestone strata. There is little doubt that this formation grows rap­idly more calcareous eastward and southeastward, and that its limestone f acies lies in this direction from the outcrop in North-Central Texas and not far from the outcrop. Passing down the Red River valley, however, this does not hold, for the formation is marly in the Tishomingo quadrangle and near Bennington, Oklahoma, where it has essenti.ally the same lithology and fossils as in Tarrant County, Texas. WEST TEXAS In the Cerro de Muleros section, Bose's subdivision 81 consisting of yellow marls containing Schloenbachia sp., Pecten subalpinus (Bose), Exogyra whitneyi Bose,2 Hemiaster calvini Clark, Protocardia texana (Conrad), and Enallaster bravoensis Bose, is Grayson. It overlies the Mainstreet formation, here a sandstone, and underlies subdivision 9, a i Bose: Inst. GeoI. Mex. Bol. 25, p. 27-28. 2Bose: Univ. Texas Bull. 1902, p. 10. University of Texas Bulletin limestone which may be either Grayson or Buda, probably the latter; this underlies the Woodbine (Dakota) sandstone. The Kent section contains equivalents of Weno and Pawpaw in division 3 of Dumble and Cummins1 section, which however does not permit of more precise definition. A north-south line drawn two miles east of Roanoke, Denton County, therefore delimits the marl facies of the Grayson from the transitional beds to the limestone facies, since east of this line the Grayson becon:ies calca­reous. This line however probably turns east since on going down the Red River valley it leaves the marl facies of the Grayson to the north at seen at Denison, Bennington and numerous other places in Southern Oklahoma. What relations exist east and south of these pointsi depends on well records not yet investigated. South of the Brazos River near Waco there is at the Grayson outcrop a transitional zone to the southern clay facies (zone of Gryphea mucronata, upper half of the Del Rio Clay) which continues west­ward to the El Paso region. The sand facies is unknown but is to be ex­pected in the removed areas of North Central Texas, in the isolated Upper Washita remnants of the Panhandle not yet _investigated, and in the Tu­cumcari region. Limestone faciea: The limestone facies, on the other hand, lying southwards in Sonora and Chihuahua is still unidentified in Texas, except at . one point, the Mariscal Mo~ntains, at th~ south tip of the Big Bend region.2 MAINSTREET Sand faciea: At Cerro de Muleros, near El Paso, Texas; apparently near Santa Rosa, New Mexico (Dr. Bose). Clay facies (Del Dio Clay, in part) : The Del Rio Clay is poorly known, and there~ore its correlation is tentative. It is equivalent to the Grayson and the upper part of the Mainstreet, and contains the following fossil levels: (1) N odosaria texana Conrad. A zone of abundance above that of Exogyra cartledgei. Bose3 in the upper 30 feet of the formation, which at Shafter reaches a thickness of 190 feet. Below this zone of abundance N odosaria is scattering. (2) Gryphea mucronata Gabb. Upper half of the Del Rio Clay. (3) Exogyra arietina Roemer. Rare near the middle of the clay in 1Dumble and Cummins: Amer. Geol., xii, 1893, 309. 2 Udden, Baker and Bose: .Univ. Texas Bull. 44, 1919, p. 76. 3Bose, Univ, Texas Bull, 1902, · · · W eno and Pawpaw Formations West Texas, abundant lower ; in Central Texas (South Bosque, Round Rock, Austin) it is abundant in the basal half of the formation but rare or wanting above. · It also occurs in the top of the Georgetown limestone at Austin. (4) Turrilites brazoensis Roemer occurs in the lowest five feet of the Del Rio Clay at South Bosque and at Austin; its main zone of abundance is in the top of the underlying Georgetown limestone. · Zones (1) and (2) are Grayson; zones (3) and (4) are Mainstreet; or briefly the upper part containing Gryphea mucronata is Grayson, and the lower part containing Exogyra arietina is Mainstreet. The Mainstreet equivalents locally have sandy levels in Central Texas, as for instance at the top of the Georgetown limestone at South Bosque and in the E. arietina slabs at Austin. Westward from the turning point of its outcrop in Bexar County the Del Rio becomes sandier and more flaggy and contains sandy slabs with Nodosaria and other fossils. At the south end of the. Quitman Mountains the Del Rio is transitional, showing a mixture of sand and clay facies, and at Cerro de Muleros the Mainstreet, represented by Bose's sub­division 7 is sandstone. North of the turning point the typical Central Texas section continues to the Brazos, where the Del Rio differentiates into two portions by the intercalation of limestone strata basally; this basal part becomes upper Mainstreet and the upper marlier part becomes Gray­son. The lower Mainstreet however continues as a limestone into Central and West Texas. Marl facies: The upper Mainstreet formation in McLennan County is transitional from clay to marl, and _at South Bosque is rather calcareous. North of the Brazos this calcareous marl contains limy seams which become more prom­inent and take on the interbedded appearance of the Mainstreet limestone of North Texas. Limestone facies: · The typically developed Mainstreet limestone between the Brazos and the Red Rivers shows this lithological facies. There is considerable inter­bedded marl as far north as Gainesville. Eastward from Gainesville, down the Red River Valley, at Cedar Mills, Denison, Bennington, Bokchito and near Hugo, the marl is more reduced in amount, and the formation consists of compact, slightly marly, massive shell breccia ·or indurated limestone with typical Mainstreet fossils. 20 University of Texas Bulletin PAWPAW FORMATION The Pawpaw formation shows along its north-south outcrop an almost idealized sequence of marine facies. Sand facies: Red River Valley, as far south as the southern border of Cooke County, Texas. Clay facies: . Denton, Tarrant and Johnson counties, Texas, to near Riovista. Marl facies: Johnson and HiU counties, Texas. Limestone facies: The equivalents of the Pawpaw south of the Brazos are questionabJe. If it is represented in this region, it is the upper part of the Georgetown limestone. (See page 11.) In West Texas its exact equivalent is unknown. At Cerro de Muleros however a distinct Weno and possibly Pawpaw fauna are present in Bose's subdivision 6, but not enough distinctive Pawpaw species are recorded to decide how much of this subdivision represents it. A hiatus at the base and at the top of the Pawpaw has been noted by Stephenson/ near the Red River, but it is unlikely that this accounts for any great thickness of Wash­ita sediments. WENO FORMATION Sand facies: There is sand in the upper half of the Weno, in the Red River Valley, Denison, Cedar Mills, Gainesville, Texas. In the lower half of the W eno : unknown. At Tucumcari, New Mexico, Dr. Bose found a sandstone, prob­ably Weno-Pawpaw, containing Ostrea quadriplicata Shumard, Turritella sp., Protocardia multistriata (Shumard), Protocardia sp. aff. texana (Conrad), Gryphea dilatata Marcou2 and other fossils. Clay (shale) facies: Red River Valley, Gainesville and Denison, Texas. Contains a few thin ironstone seams ; southward and to a less extent eastward this facies be­comes marly and is intercalated with thin limestone seams. Marl f.acies: Denton, Tarrant, Johnson and Hill. counties, Texas. The upper ·half of the Weno is limy at places (as Fort Worth) where the lower half is marly. The formation is prevailingly of limestone throughout, south 1Stephenson: U. S. G. S., Prof. Paper 120-H, p. 143. 2 Marcou: Geology of North America, plate IV, figures 1, la, 3, 1842. W eno and Pawpaw Formations of the Brazos River. In West Texas at Cerro de Muleros, the Weno is rep­sented in Bose's subdivision 6, which consists of marls, sandstone and lime-. stone. This series is therefore composite and transitional, like the Weno at Gainesville and Denison, and contains many identical fossils. Limestone facies: Po:r:tion of the Georgetown limestone near top, south of the Brazos. An indurated, massive limestone facies is unknown but probably lies to the east and south of the outcrop in Central Texas. DENTON FORMATION Sand facies: Unknown. Clay facies: From Blue Mound, near Haslet, Tarrant County, Texas, northward to Denison. Contains pyrite and crustacean fauna. Marl facies: In North-Central Texas along the outcrop the marl f acies appears below Blue Mound, just north of Fort Worth and continues southward. In southern Oklahoma, the Red River Valley and Central Texas north of the Brazos, this formation is a clay, slightly arenaceous at the base and capped by shell conglomerate. This ·conglomerate is much more conspicuous at the Red River than at Fort Worth and southward, where it has largely disappeared, leaving a very shelly marl. South of the Brazos River, near Waco, there is a transitional zone between the marl anfi the limestone facies. At Cerro de Muleros a portion of subdivision 5 is a gray marl containing great numbers of Gryphea washitaensis Hill, and represents the Denton. Limestone facies: The portion of the Georgetown limestone which represents the Denton formation is a consolidated. shelly limestone with very little calcareous cementing material, and usually massive without marl interbedding. It extends from a point near Waco southwards to the turning point of the Comanchean outcrops in Bexar County and thence westward to beyond the Pecos River. In the El Paso region, however, the equivalent to the Denton belongs to the northern (littoral-bathyal) fa;cies and is marly as · in North Texas. FORT WORTH FORMATION This formation is calcareous over all of North and Central Texas but is somewhat marly in the Red River valley and is prevailingly marly near El University of Texas Bulletin Paso. A line connecting these two areas will give very roughly the boun­dary between the marl and lime areas. Sand fades: Unknown. Clay facies: Unknown. Marl facies: Cerro de Muleros, near El Paso, gray to bluish marls; Denison and east­wards, marly limestone and marly interbedding. Limestone facies: South of the Red River and throughout North and Central Texas at the outcrop. The middle portion of the Georgetown limestone represents this facies. A deeper sea subphase found in southern Trans-Pecos Texas con· sists of hard, crystalline, sparsely fossiliferous, relatively pure, fine grained lithographic limestone, which composes most of the Georgetown and Buda. This is the purest and probably the deepest sea deposition known for this formation. DUCK CREEK (Upper) Sand facieil: Unknown. Marl facies: This group of strata is prevailingly a calcareous marl and contains the least limestone at Gainesville. At Fort Worth it has only slightly more fime than at Gainesville, while at Denison and at Caddo, Oklahoma, it is distinctly more limy. The change from marliness to liminess therefore appears to be in this region at least largely an east-west change. The Duck Creek marl thickens to the northwest, being thickest near Denison and thicker in the Tishomingo than in the Atoka area. · Limestone facies: South of the Brazos-Colorado River divide, the Duck Creek marl is im­bedded in the base of the Georgetown limestone, where it is a marly im­pure limestone. The situation in West Texas is unknown. DUCK CREEK (Lower) Sand fades: Unknown. Ther9 are some bituminous sandy layers in the Duck Creek in Cooke County, Texas, but these appear to be local. Shale (day) facies: Seen at the type locality, three miles north of Denison Texas. This ­shale is somewhat calcareous and is transitional to a marl. ' Weno and Pawpaw Formations • Marl facies: This facies invades the limestone series at Gainesville, Texas, where all of the lower Duck Creek except the basal ten feet is prevailingly marly. Probably the removed portion of the Duck Creek west and north of the outcrop was prevailingly marly. Limestone facies: Extends from Denton County south.ward to the turning point -of the Comanchean outcrop in Bexar County, and thence westward to the Trans­ . Pecos region. The group of strata is composite and at a given point is more marly above than below. For instance, at Denison the Hamites and Desmoceras zones are prevailingly limy marl with some blue shale, and at Denison the zone of Desmoceras brazoense is marly at the top; at Fort Worth the section is limestone to the top of the Schloenbachia trinodosa horizon and limy even above this ; while below the Brazos the whole lower Duck Creek section becomes limy. South of the Brazos the Duck Creek formation lies at the base of the Georgetown limestone where it is a chalky white indurated rather un­f ossilif erous limestone, differing considerably in appearance at Austin and at Georgetown, Texas ; while west of the southern turning point.of the outcrop it becomes a hard, crystalline, consolidated, sparsely fossilifer­ous limestone. At Cerro de Muleros near El Paso, on the contrary, the northern littoral facies is present as at Gainesville and Denison and this level is represented by a series of clay, marl and limestone, which repre­sents a transitional facies. Vraconian faunae from Chihuahua and Zaca­tecas (p. 60) represent in part this stratigraphic level. KIAMITIA FORMATION Sand facies: Unknown. Clay (shale) facies: From near Primrose, southwestern Tarra·nt County, south througn Johnson County to beyond the Brazos. This formation at Blum, Hill County, is a yellowish clay 19 feet thick. This facies contains a con­spicuous limonite fauna, Schloenbachia, Arca, small gastropods and pelecy­pods and other fossils. Marl facies: Southern Tarrant County to between Gai_nesville and Fink. The forma­tion is increasing in thickness northwards and as the clay facies disap­pears, flag layers enter first as limestone .in thin sheets and farther north as shell conglomerate sheets. The bulk of the formation is marl, and the limonite fauna has largely disappeared. Un,iversity of Texas Bulletin • Lime f.acies (conglomerate): Fink, Grayson County, Texas, to east of Hugo, Oklahoma. Coincident­ally on passing eastwards and northwards from the marl facies the scat­tered shells in the formation become consolidated into conglomeratic sheets with shelly marl between, and these predominate at Gainesville and Deni­son. Turning east down the Red River Valley the thickness of the Kia­mitia and the amount of this conglomerate greatly increase. Near Hugo, Oklahoma, the Kiamitia shell conglomerate is about 150 feet thick and is extensively used for crushed rock. This formation is a shallow water oyster bed deposit of mixed Fredericksburg and Washita fossils, mainly the former. The formation disappears at the Brazos-Colorado uplift, and in West Texas its relations are unknown. EDWARDS FORMATION The Fredericksburg Division also must be considered sectionally, since its various parts behave differently as to their changes of thickness and lithology. , Sand facies: Unknown. Clay facies: Unknown. Marl facies: Unknown. Bose's subdivision 3 at Cerro de Muleros contains some marl, but this subdivision is not positively known to be Edwards. Through­out the Red River region and North-Central Texas, the top of the Good­land, which is thought to correspond to the Edwards, is a non-marly lime­stone, usually massive and sometimes crystalline. North of Sheffield and Fort Stockton, the Fredericksburg is stated to be prevailingly marly. Limestone facies: This is known from Fort Worth south to the turning point of the out­crop in Bexar County, and thence west to El Paso. The Red River ex­tension of this level is not identifiable with certainty because it is not clear whether the 12-20 feet of white)imestone at the top of the Fredericks­burg division as seen at Denison or north of Goodland, Oklahoma, repre­sents only the Edwards or also in part still lower Fredericksburg. The Edwards is less than 10 feet thick at Fort Worth; it is 33 feet thick at Comanche Peak, and southwards thickens rapidly. Rudistid facies: The Rudistids invaded Texas most widely in upper Fredericksburg time, when they were scattered as far north as Fort Worth; however, they are very rare and inconspicuous north of the Brazos, in Central Texas. In W eno and Pawpaw Formations West Texas they are reported as far north as Bailey County, and they are common in Coke and Runnels counties. In Trans-Pecos Texas, the Texas and Pacific Railway roughly divides the southern rudistid facies of the Edwards from the northern littoral f acies. The rudistids are rare or wanting at Cerro de Muleros, Kent, Sierra Blanca and the Finlay Mountains; and present at points between these and the Rio Grande. Gabb1 describes from the Sierra de las Conchas near Arivechi, Sonora, fossils which if correctly identified include among diverse stratigraphic levels that of the Edwards limestone; the facies represented is unknown to me. Felix and Lenk2 also record the great extent of the Fredericksburg reef facies in Mexico. WENO AND PAWPAW FORMATIONS The influence of the underlying syncline on the deposition of these two upper Washita formations is small, due to their small thickness. However, they show an appreciable syncline in the Fort Worth region, and a con­spicuous thinning southward. Since the maximum rate of change of thickness, like the maximum change in lithology, may not coincide in direction with the outcrop, the formation along the outcrop will in general show only a greater or less north-south or an east-west component of change in thickness or lithology and the maximum change will be in a direction lying at an angle to the qutcrop. THICKNESS CHANGES North-South Changes This is true of the north-south outcrop of the two formations, which does not exactly coincide with the direction of greatest thickness change. The Weno and Pawpaw strata outcrop in a line passing about a mile east of Gainesville, Cooke County, and thence nearly south to near Denton; thereafter the boundary between the two formations runs near Fort Worth, west of Cleburne, Riovista and Blum. The outcrop thus from the Red River to the Brazos has a general trend of east of north, while the direction of greatest_ thickness change is slightly east of north. (See figure 3) . 1Gabb: Pal. Cal, vol. 2, p. 257 ff. 2Felix and Lenk: Beitr. z. Geol. u. Pal. d. Rep. Mex., II, p. 28. 26 University of Texas Bulletin East-West Changes (North Texas and Oklahoma) In the whole Red River region these two formations at their outcrops maintain an almost uniform thickness, but they are slightly thicker east­ward as far as Choctaw County, Oklahoma. Their behavior east of this point is unknown to me. TABLE OF APPROXIMATE THICKNESS OF WENO AND PAWPAW FORMATIONS Weno Paw- Locality Lower Upper Total paw Denison ......................... . 45 80 125 50 Gainesville .... . .. . ........ . ..... . 40 70 110 44.8 Blue Mound (Haslet) ............ . 27.3 Fort Worth ............... . ..... . 12.7 49.6 62.3 24.6 Riovista 10 25 35 5.0 LITHOLOGICAL CHANGES The Weno and Pawpaw formations are marked by striking lithological changes which produce along their outcrops localized lithological regions each with a characteristic fauna. The Pawpaw formation, and to a less extent the W eno, passes from north to south along its outcrop through a "typical" series of lithological facies-sand-clay-marl-limestone, which aside from various complicating factors of deposition is usually taken to represent a progressive series of marine facies from near-shore to off­shore conditions. Likewise the problem of localized faunales is vividly impressed upon one by the situation in the Pawpaw clay (as also in the Weno), where within a few miles one fauna largely disappears and an . equally rich and varied, but different one occupies its stratigraphic posi­tion. For example the Gainesville-Denison fauna (Nacreous, Arca), the Fort Worth fauna (Turrilites, Engonoceras, Hamites, Scaphites) and the Riovista fauna (Flickia, echinoids) of the Pawpaw formation represent three different marine facies. The narrow ribbon-like outcrop of these formations in North Central Texas and Southern Oklahoma gives only a limited opportunity for the study of these different marine phases, but the following regional differences in the sediments of these formations are ap­parent. Weno and Pawpaw Formations 27 PAWPAW Nature of Material FORMATION Locality of Outcrop Facies of Marine Deposition Choctaw county, Oklahoma Marshall county, Oklahoma (a) Semi-consolidated sandstone and Bryan county, Oklahoma ironstone . . . . . • . . . . . . . . . . . .. . Love county, Oklahoma Neritic Grayson county, Texas Cooke county, Texas (b) Clay with sandy layers........ . { Denton county . Tarrant county Bathyal (c) Marl with limy layers.......... { Johnson countyHill county (d) Limestone....... . ..... . ...... . South of Brazos River Deeper Sea UPPER WENO (a) Shale with sand layers and iron-{ Grayson county stone . . . . . . . . . . . . . . . . . . . . . . . Cooke county Neritic (b) Marl with lime layers...-. . . . . . . Denton county Bathyal (c) Limestone. . . . . . . . . . . . . . . . . . . . . . Tarrantcountyand southwardDeeper Sea (in part Zoogenic) LOWER WENO (a) Shale with sand layers. ... . . . . . Red River region Neritic (b) Marl and limestone layers.... . . . Cooke county to Brazos RiverBathyal (c) l;imestone.......... ........... . South of Brazos River Deeper Sea PAWPAW FORMATION Eastward from the turning point of the Comanchean outcrops in the Red River uplifted area near Orlena, Cooke County, Texas, the Pawpaw is a ferruginous sandstone or an unconsolidated sand. . This outcrop runs down the Red River valley in a direction a little south of east, lying in Cooke and Grayson Counties, Texas, and in Love, Marshall, Bryan, and Choctaw Counties, Oklahoma. Sandstone Faciea ·(a) (Semi-consolidated Sandstone and Ironstone) 1n general, the Pawpaw formation is prevailingly sandy and iron bear­ing at its outcrops north and east of the south border of Cooke County, Texas. University of Texas Bulletin Near Gainesville, the formation is a series of thickbedded, hard, ferru­ginous sandstones with interbedded, laminated impregnated sandy layers and semi-consolidated iron-impregnated sand. The layers are locally a shell conglomerate containing great quantities of casts of Arca, Turritella and other bivalves and gastropods. The basal layers are characterized by an abundant pyrite fauna. Turrilites, Scaphites, Hamites and echinoids are rare or absent. This type of lithology continues around the turning point of the Comanchean formations south of CJrlena to a point near Potts­boro; and at Denison the Pawpaw formation is almost entirely a coarse consolidated brownish-red sand with few _fossils. At Durant the formation is similar to the Denison exposures. Eastward through Bennington and Bokchito the sandy phase continues, and is included tn the Bokchito for­mation of Taff. SECTION OF SUGAR LOAF MOUNTAIN, BRYAN COUNTY, OKLAHOMA Section 22, R. 12 E., T. 5 S. (furnished by W. M. Winton) MAINSTREET: Limestone, iron stained, old cap of hill, practically removed by weathering. Feet PAWPAW: Massive yellow red sandstone, soft in fresh exposures, indurated where long exposed; no fossils seen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . 0 Soft limonitic sand; no fossils seen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30. 0 Ironstone ledge composed of fossils (Arca sp., Ostrea quadriplicata, small ammonites, gastropods, etc., a typical Pawpaw fauna)................ 0.5 Red sand, cross bedded and containing lenticular hard masses of sandstone 10. O Ironstone ledge composed of fossils (Arca sp., Ostrea quadriplicata, am­ monites, N odosaria, etc., a typical Pawpaw fauna) . . . . . . . . . . . . . . . . . . O. 3 Red sand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . ·10. 0 WENO: Yellowish hard limestone with typical W eno fossils. . . . . . . . . . . . . . . . . . . . . . . O. 8 Soft marl; no fossils seen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. 3 Very hard massive limestone, pinkish in color. Large numbers of fossils having same hardness as matrix and giving uniform fracture. Ledge forms conspicuous topographic break traceable for miles. Schloenbachia sp. M., and other typical Weno fossils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9 Soft marl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15. o Limestone ledge sandy; no fossils seen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.o Soft marl with a few thin limestone ledges, each less than 0.5 feet thick.... 95.0 DENTON: Conglomerate of Gryphea washitaensis, Ostrea carinata, and other Denton fossils. Typical Denton marl ("Caddo" limestone of Taff, top). Ex­posed, about . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. o Weno and Pawpaw Formations In the creek, one-fourth mile west of the mountain, the contact between the Duck Creek marl and the Fort Worth limestone is exposed as at Caddo, Oklahoma. In the second cut llh miles north of Hugo, Oklahoma, there is 10 inches of shell conglomerate containing abundant juvenile and adult Ostrea quadriplicata Shumard, Gryphea washitaensis Hill, Plicatula sp., Pecten subalpinus (Bose), abundant Leiocidaris spines, Corbu"la littoralis Adkins, and other typical upper W eno fossils as found at Gainesville and Denison. This represents part of the Quarry limestone group. Above it is an iron­stone ledge, 4 inches thick, which is red-stained and conglomeratic and re­sembles the basal Pawpaw as seen at Gainesville. Along the St. Louis and San Francisco Railway track between Benning­ton and Bokchito, Oklahoma, the upper Washita section, Woodbine to Weno, is seen to advantage. The Grayson marl with an estimated thick­ness of 50 feet is well developed with its characteristic fossils.1 The Mainstreet limestone is seen in roadside cuts one mile northwest of Be.nnington, in the caprock of Sugarloaf Mountain, six miles north of Ben­nington, in the bed of Sulphur Creek, where it forms an extensive pave­ment limestone,·and in the railroad cuts nearby, particularly in the long cut running west down to Bokchito Creek, which has it well exposed. Everywhere it is underlain by the brown consolidated Pawpaw sandstone. The nature of the Pawpaw and Weno outcrops in this region is seen from the following section. SECTION OF CUT NEAR SULPHUR CREEK, ON THE ST. LOUIS AND SA1'1 FRANCISCO RAILWAY, TWO MILES WEST OF BENNINGTON, OKLAHOMA MAINSTREET: Feet Brown limestone with Turrilites brazoensis, Pecten subalpinus, Exogyra sp. (large), and ammonites. The top of the exposure is an Exogyra arietina conglomerate. Exposed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Brown-blue limestone with irregular sandy inclusions. . . . . . . . . . . . . . . . . . . . 1 Yellow limestone containing Kingena wacoensis, Ostrea marcoui, and Pecten subalpinus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. 5 1Taff (U. S. G. S. Geologic Atlas of the United States, Atoka Folio, No. 79) has overlooked the Grayson marl, which in this quadrangle is typically developed as at Denison. It may be seen near the Woodbine ("Silo") sandstone knob mapped by Taff one mile northwest of Bennington, Oklahoma, where it overlies typical Mainstreet limestone containing Turrilites brazoensis Roemer, Exogyra arietina Roemer and othet distinctive fossils, and contains Gryphea mucronata Gabb, Gryphea, sp. (truncate) Pecten subalpinus (Bose), Plicatula sp., Ostrea sp. aff. subova~a; Shumard, and Engonoceras sp. This locality is mentioned by Taff, ibid., p. 6. It also forms the overburden in the Mainstreet quarry one mile north of Durant, Oklahoma, where it is very fossiliferous. . 30 University of Texas Bulletin PAWPAW: Consolidated brown sandstone, no fossils seen. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Unconsolidated sand, iron stained ........................ . .......•• , . . 10 Blue jointed clay with scattered Gryphea................................ 10 lfod-brown sandstone--calcareous in part-with nacreous and ironstone fos­ sils: Arca, Nucula sp., Corbula sp., Cerithium, Turritella, Anchura, like the Gainesville and Denison nacreous fauna. . . . . . . . . . . . . . . . . . . . . 1 Marl, containing ironstone seams, no fossils seen. . . . . . . . . . . . . . . . . . . . . . . . . 10 The cut east of the Bokchito Creek bridge shows the foregoing section much better exposed. Pawpaw exposures were also noted near Durant, Oklahoma. North of the railroad, 11/2 miles east of Bennington, Oklahoma, about 50 feet of massive brown sandstone was noted underlying the Main­street limestone at the top of the hill. This sandstone contains limy layers bearing Ostrea quadriplicata, 0. subovata ( ?) , marcoui, Trigonia sp., Gry... phea sp., and Pecten sp. (large). Taff gives the following section for his Bokchito formation in the Atoka and Tishomingo quadrangles1 : SECTION OF THE BOKCHITO FORMATION IN THE ATOKA AND TISHOMINGO (OKLAHOMA) QUADij.ANGLES J. A. Taff, 1902-1903 Feet 4. Sandy and clay shales, and locally friable, cross bedded sandstone. In the clay and in some of the iron and lime concretions, shells· are preserved with original nacre . . . . . . . . . • . . . . . . . . . . . . . . • • . . . . • • . • . . . • . . . . . • . 50 3. Hard, semi-crystalline, bluish, oyster shell limestone, weathering yellowish and projecting as ledges separated by friable shales................ 10-20 2. Friable sandstone beds, locally cross bedded, alternating with and including deposits of sandy clay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-30 1. Sandy clay shale, with ferruginous limestone segregations and ironstone nodules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 170-19() This thickness is given as 140 feet in the texts and the Columnar Section sheets of both folios. The upper member ( 4) of this section is probably Pawpaw. Sheets of nacreous shells in the Pawpaw have been noted in Grayson County. The other three members are W eno. The Pawpaw formation is exposed in the hilltops east of Denison and 1Taff: U. S. G. S., Geologic Atlas of the United States, Atoka Folio No. 79, 1902. p. 6; and, Tishomingo Folio, No. 98, 1903, p. 6. Weno and Pawpaw· Formations 31 may be seen in cuts on East Main Street, where it is a cross-bedded rather consolidated, brick red sandstone. No fossils were seen at this locality. The formation is stated by Stephenson1 to be 50 or more feet thick near Denison. The Pawpaw is poorly exposed north of a west branch of Little Mineral Creek just south of Fink, where it is steeply tilted. On the Red River about 2 miles northwest of Cedar Mills, Grayson County, there is a long cliff dipping west (5°) which exposes near the top about 40 feet of loose sand only partially consolidated, which is probably Pawpaw.· SECTION OF. BLUFF OF RED RIVER TWO MILES NORTHWEST OF CEDAR MILLS, GRAYSON COUNTY, TEXAS MAINSTREET: Feet White limestone with Ostrea quadriplicata, Turrilites brazoensis, Kingena, Exogyra arietina, Pecten subalpinus, Enallaster sp. aff. texanus. Seen i:Q ravine above east end of river bluff near road..................... . .. 10 PAWPAW: Sandstone with thin ferruginous layers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Blue marl with clay and sand seams and nacreous fossils: Engonoceras, Corbula, Nucula, Ostrea quadriplicata, Pecten subalpinus . . . . . . . . . . . . . . 30 QUARRY LIMESTONE ( ?) : Massive grayish semi-crystalline limestone .................... ~ . . . . . . . . . . . 2 WENO: Blue marl with nacreous fossils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 The roadside cuts 21/2 miles east of Gainesville, Cooke County, inconsec­utive sections of the Pawpaw are seen. The interval from the top of the Quarry group to the base of the Mainstreet limestone is not less than 45 feet. The base of the Pawpaw overlying the Quarry limestone is seen in a cut of the Missouri, Kansas and Texas railway (Wichita Falls branch) at the north end of the brickyards pit 13,/,i. miles southeast of Gainesville. This exposes about 8 inches of an irregularly deposited reddish ferrugin­ous shell conglomerate largely of Ostrea quadriplicata-cemented into the pitted surface of the Quarry limestone. The same level is exposed near the water tank on the southwest rim of the pit. In roadside cuts %i. mile southeast of this locality about 45 feet of Pawpaw may be seen poorly ex­posed; it consists of thin layers of ferrugin_ous dark red brown sandstone which, locally at least, consists of cemented masses of ironstone fossil c~sts : Arca, Protocardia, Nucula, Corbula, Turritella and rare Ostrea quadripli­cata and Gryphea. These ironstone layers are interbedded with brown to istephenson, U. S. G. S., Prof. Paper 120-H, p. 142. University of Texas Bulletin yellow, softer, ferruginous, very arenaceous clay. Their ironstone seams do not exceed 6 inches in thickness and locally are highly indurated. SECTION OF THE PAWPAW FORMATION IN ROADSIDE CUTS TWO ANJ:; ONE-HALF MILES SOUTHEAST OF GAINESVILLE, TEXAS Section furnished by W. M. Winton MAINSTREET: White massive limestone with characteristic Mainstreet fossils. Exposed. . . Feet 6 PAWPAW: Alternating red ironstone and ferruginous sandy clay layers. About 16 compact ironstone layers each 3 to 4 inches thick, alternating with clny layers each about one foot thick. The ironstone layers are similar from bottom to top and the basal 10 feet is more fossiliferous than the upper portion. The ironstone layers contain: Remondia sp., Trigonia sp., Arca sp., Engonoceras sp., Nucula sp., Corbula sp., and other nacreous and ironstone fossils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ·Brown sandstone flag layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Red ironstone layer with Nodosaria texana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Brown clay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Red ironstone with Arca sp., Ostrea quadriplicata . . . . . . . . . . . . . . . . . . . . . . . Brown clay, sparsely fossiliferous: Arca, gastropods. . . . . . . . . . . . . . . . . . . . . . Red calcareous sandstone: Ostrea quadriplicata . . . . . . . . . . . . . . . . . . . . . . . . . 21 . 5 0. 5 0. 3 5. C 0. 5 15. C 2. 0 This is underlain by the Quarry Limestone group (see page 36). The thick semi-consoli'dated sand seen in Grayson County is absent. The Paw­paw outcrop which has turned nearly south at the turning point near Or­lena, makes a narrow north-south strip from Gainesville to the southern border of Tarrant County. The ironstone facies does not persist past the Trinity River, since interstratified clay lenses here largely make up the formation; as far south as Fort Worth there are large amounts of weath­ered ironstone fragments in the surface debris of the Pawpaw.1 Clay Facies This facies of the Pawpaw formation is best developed in the Fort Worth region. From Cooke County southward to the Brazos the Pawpaw is rap­idly thinning, as previously described. At the same time, passing south­ward through Denton and Tarrant Counties the clay facies is encountered, and in the region of the Brazos the marl facies appears. The clay facies grades into each of the other two facies, so that the transitions are gradual. This gradation occurs through the invasion of one facies by seams of the other kind of material. 1Winton and Adkins: Univ. Texas Bull. 1931, p. 67. W eno and Pawpaw Formations The transitional zone from the ironstone to the clay facies occurs in Den­ton and northern Tarrant Counties. As far south as the Trinity River con­siderable amounts of ironstone fragments occur in the Pawpaw exposures; these are the residue of numerous thin ironstone ledges similar to those of the Red .River area but sparsely fossiliferous, which are scattered rather evenly throughout the formation. The interbedding material is an arena­ceous clay. South of the Trinity the section is prevailingly clay but has thin ironstone, limestone and sand seams. SECTION OF THE PAWPAW FORMATION AT BLUE MOUND ONE AND ONE­HALF MILES SOUTH OF HASLET, TARRANT COUNTY, TEXAS MAINSTREET: Feet White chalky limestone, exposed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 PAWPAW: Brown to yellow, sparsely fossiliferous clay, with thin ironstone seams and scattered sand lenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Sandstone flag layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0. 3 Brownish yellow impure clay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Thickness of Pawpaw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27. 3 On Sycamore Creek, three miles southeast of Fort Worth the Pawpaw has an average thickness from several measurements of 7.5 meters (24.6 feet) . At the southern border of Tarrant County the Pawpaw is 12 feet thick· and is transitional to the marl facies. In northern Johnson County the transitional zone continues and the section consists of clay mixed with marl. Passing from the upper Noland's River southeast to Riovista the section changes considerably, for from Riovista southward the marl facies is found, with little clay and no ironstone; there is also a corresponding change in the Pawpaw fauna. SECTION OF BRANCH OF NOLAND'S RIVER NEAR CLEBURNE-WEATHER­FORD ROAD, 10 MILES WEST OF CLEBURNE, TEXAS Section furnished by W. M. Winton . MAINSTREET: Feet Massive limestone containing Pachymya sp., Turrilites brazoensis, H olectypus limitis, Pecten sp. . ......................... ...........· . . . . . . . . . . . . 32.4 PAWPAW: Reddish clay containing fragments of Turrilites sp., Arca sp., etc., pyritized 10. 8 WENO: Limy marl capped by a hard lime ledge one foot thick, containing Pecten georg.etownensis, Nautilus texanus, Pinna sp., Kingena sp. . . . . . . . . . . 7 .8 34 University of Texas Bulletin Marl, containing N odosaria texana ...........•........... J • •••• • • • • • • • • 1.0 Massive limestone containing Schloenbachia sp. M. (notched tubercles), Nautilus texanus, Epiaster sp., Protocardia sp., Gervilliopsis invaginata (one) ............... · · · · · · · · · · · · · · · · • · · · · · · · · · · · · · · · · · · · · · · · · · · · · CONCEALED BY BED OF STREAM, ESTIMATED................. ·· 7.4 10.0 Soft whitish marl! no fossils seen ...................................... . 10.0 Marl F:aciea The transition from clay facies to the marl facies of this formation takes place rather abruptly, within a distance of 2 miles along the outcrop and terminates in central Johnson County, south of which the formation is al­most entirely marly. One mile southeast of Riovista, the Pawpaw is a dis­tinctly marly uniform light yellow, fossiliferous· deposit lying between the conspicuous W eno and Mainstreet limestones. It is about 5 feet thick. In the territory covered by this depositional phase the conspicuous pyrite fauna of the Fort Worth region is rare, except a few Turrilites, Arca and small gastropods, and other fossils, echinoids and ammonites are abundant. SECTION ON W ACO-RIOVISTA ROAD, ONE MILE SOUTH OF RJOVISTA, TEXAS MAINSTREET: Feet Massive white limestone with characteristic Mainstreet fossils: Turrilites brazoensis, Kingena, Exog.yra arietina. Exposed . . . . . . . . . . . . . . . . . . . . 5 PAWPAW: Homogeneous calcareous, straw-yellow marl with a few ironstone and calca­reous fragments, containing Enallaster bravoensis, E. wenoensis, E. riovistae, Holaster sp., Epiaster wenoensis, Plicatula sp., *Flickia boesei, *Schloenbachia sp., *Turrilites sp., *Arca washitaensis................ 5.5 WENO: Limestone escarpment in two terraces, poorly exposed at the base, consisting of massive soft limestone with marl interbedding. Contains EnaUaster, Epiaster, Holaster, Hemiaster calvini, Pecten subalpinus, Plicatula and many other fossils, Trigonia clavigera. About . . . . . . . . . . . . . . . . . . . . . . 40 DENTON: Soft light straw-colored marl containing Gryphea was'hitaensis, Ostrea cari­nata, Pecten subalpinus, Plicatula sp., and Kingena sp. (large)........ 5 LIMESTONE FACIES: The equivalents if any of the Pawpaw forma­tion in Central Texas are largely insignificant since they consist of only a minute thickness of very calcareous marl and limestone imbedded in the top of the Georgetown limestone, underneath the Turrilites brazoensis zone which represents the basal Mainstreet formation of North Texas. This sit­uation presumably exists westward to the Tran$-Pecos region wherever the Weno and Pawpaw Formations more southward section "is found. However, i!li West Texas, on passing northward into the near-shore facies (as at Kent and Cerro de Muleros) the Weno and Pawpaw formations again thicken, as in passing from Austin to Fort Worth, and show characteristic and so far as can be judged from published accounts ,similar fossils. This level at Muleros has echinoids and ammonites and.other distinctive fossils (see page 41), but so far the large .pyrite fauna of the North Texas Pawpaw has not been reported from West Texas. WENO FORMATION A summary of the marine facies of the Weno formation and several ge­ ological sections have already been given. The Weno formation is compos­ ite, and represents different phases of marine deposition both at different places and in its different levels at the same place. In the Red River region the formation is mostly a series of blue shales with clay-ironstone, lime· tone _and irregular consolidated sand seams. The ironstone and shale lay. ers are rich in nacreous fossils. The shale is here capped by the Quarry limestone group, which loses its massive character south of Denton County. Passing southward from the Red River, the basal Weno transforms from a clay into a calcareous marl with shelly, often slabby, limestone seams and the upper part after passing rapidly through a . marl stage becomes pre­ vailingly a soft chatky fossiliferous limestone. This is the situation in Den­ ton and Tarrant Counties. The basal division is also :capped by a thin chalky limestone which forms a bench, and the W eno thus consists of two terraces, a persistent topographic feature which passes southwards across . Denton, Tarrant, Johnson and Hill Counties and disappears only in north­ western McLennan County where the Weno limestone consolidates with the Mainstreet and Fort Worth limestones (by the virtual disappearance of the intervening softer formations) to form the middle Georgetown lime­ stone. In the Red River region the shale (clay) facies predominates from south­ ern Cooke County to east of Bennington, Oklahoma. It is conspicuous in the first deep cut of the St. Louis and San Francisco Railway track north of Denison, of which a photograph is given by Stephenson,1 and in the pit of the brickyard 13,/,i, miles southeast of Gainesville ,of which a section is here given. istephenson, U. S. G. S., Prof. Paper 120-H, pl. XXII B. University of Texas Bulletin SECTION OF THE WENO FORMATION AT LOCALITY 601, PIT OF GAINES­ VILLE BRICK COMPANY, ONE AND THREE-FOURTHS MILES SOUTH­ EAST OF GAINESVILLE, TEXAS PAWPAW: Shell limestone, consisting almost entirely of masses of comminuted shells ... Shelly calcareous marl, with ironstained arenaceous cement and masses of shells. 0. QUADRIPLICATA LAYER ............................ . This stratum contains: 0. quadriplicata, Pecten subalpinus, Plicatula sp., Leiocidaris sp. spines. Hard reddish limestone composed almost entirely of comminuted shells iron-stained ...................... ·. · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Shell conglomerate of small packed shells, laminated .................... . QUARRY; Compact shelly blue to yellow limestone containing many comminuted shell fragments. QUARRY LIMESTONE . . ........................... . This stratum contains: Gryphea sp., Pecten subalpinus, cidarid spines (rare), Plicatula sp. Shell conglomerate of Gryphea washitaensis chiefly, with considerable cal­careous cement. GRYPHEA CONGLOMERATE . . .................· · This stratum, which is conspicuous as just underlying the cap rock of the rim of the pit, contains: Ostrea carinata, cidarid spines, Ostrea marcoui, Plicatula sp. WENO: Packed bluish to yellow clay, with two thin seams of Gryphe'1 shell conglom­ erate, each one inch thick........... .............................. . Sand layer containing no fossils, irregular thickness, about............... . Blue to yellow shale, with a considerable amount of sand in the form of irregular anastomosing sand lenses and streaks. Fossils in the shale .. Ironstone band .................................................. ..... . Blue to yellowish iron stained shale, with irregular calcareous concretions, locally called "ginger shale" ...................................... . The ginger concretions also occur in the sandy layer just above the ironstone seam. Fossiliferous Ironstone stratum ...... . ................................ . The clay-ironstone of this and the overlying ironstone layers has been excavated and dumped in a large heap on the east rim of the pit. Material in situ in the pit and that in this heap bears the following nacreous fossils: tProtocardia sp. aff. multistriata (Shumard), very abundant as casts and molds, with the original shell; tBarbatia sp., tCorbula basiniformis Adkins, tNucula nokonis Adkins, tNucula weno­ensis Adkins, tGlobiconcha sp., tNatica sp., tCinulia washitaensis Adkins, Cambarus (?) sp., tSchloenbachia wintoni Adkins, tGervilliopsis invaginata (White) , tPecten inconspicuus Cragin, tAnchura mudgeana (White), and many other fossils. Blue fossilif~rous shale and calcareous bands ........................... . This material is an alternation of thin bands of yellow. sandy lime- Feet 0.2 .8 .3 .5 .9 .7 1.0 .2 4.7 .1 2.5 .5 4.-0 W eno and Pawpaw Formations 37 . stone with packed laminated blue-gray shale, slate color when fresh, but weathering to blackish-blue. Fossiliferous ironstone band .......................................... . .2 Blue shale, laminated, jointed on weathering, very fossiliferous ............ . 19.8 This layer contains an abundant nacreous shell fauna, including: Gervilliopsis invaginata (White), Gryphea washitaensis Hill (juvenile stages), Enallaster sp., Tellina sp., Corbula basiniformis Adkins, Nucula wenoensis Adkins, Pecten inconspicuus Cragin, A nchura mudgeana . White, Natica sp., Turritella sp., Cerithium sp., etc. Gray-blue arenaceous laminated shale, calcareous in part, forming a terrace in the pit. G. washitaensis, Gervilliopsis invaginata, Pecten, Plicatula .3 Laminated blue shale ............................·.................... . .2 Ironstone seam . . . . .. . . . . . . . . . . .. ......... . .......................... . .1 Laminated gray-blue shale ................. . ......................... . 1.9 This works down into kidney-shaped lumps, and is locally called "kidney shale." Arenaceous laminated marl. Gryphea washitaensis abundant at top and bottom. Main zone of Gervilliopsis invaginata (White), Trigonia clav­igera Cragin, Pecten subalpinus Bose, Leiocidaris spines. This layer forms a secondary terrace ........................................ . .9 Blue fossiliferous marl. Locally called "buff marl," a desirable brick ma­terial, free from impurities, burns to buff color ................... . . 11.2 61.0 This material has been thrown in heaps onto the terrace above and is rich in small calcitic fossils, including: Venericardia wenoensis Adkins, Trochus laticonicus Adkins1 Trigonia cl<11Vigera Cragin, N eritina, Nerita, Pecten sp., worm tubes, minute corals. In the bottom of the pit covered by water is about 30 feet more of Weno . shale. It is stated that the pit has at one point been dug 70 feet deep. A water well nearby passed through the Denton marl into the Fort Worth limestone. The Denton marl is poorly exposed one-fourth mile west of the pit, and the Fort Worth limestone is finely exposed with its typical sequence. of fossil zones, in the creeks between the brickyard and Gainesville. The Quarry limestone is variable in thickness. Blocks two to three feet thick have been excavated from the pit and thrown in a heap above its south rim. An extensive outcrop, with quarried indurated blocks, three feet thick, occurs three miles east of Gainesville just north of the track. The quarry group forms a persi&tent outcrop eastward to the river near the the northeast corner of Grayson County, in which county its relations have been described by Stephenson. In Denton County on the Denton­Krum road, it outcrops as a bench, and is 15 inches thick. Here it is abundantly fossiliferous, and contains Pecten subalpinus, cidarid spines, Ostrea marcoui, Gryphea washitaensis and Ostrea carinata. Beneath it is a ferruginous and calcareous shell conglomerate layer 1 to. 2 inches thick consisting almost entirely of the last two species named. In Tarrant University of Texas Bulletin County it is consolidated with the top of the Weno formation, which is a chalky limestone. SECTION OF PAWPAW AND WENO FORMATIONS AT LOCAI:ITY 602 ON SYCAMORE CREEK, FOUR MILES SOUTHEAST OF FORT WORTH, TEXAS MAINSTREET: Feet White massive limestone, with K ingena wacoensis (? ) (Roem'er) , Turrilites brazoensis Roemer, Exogyra arietina Roemer, Pecten subalpinus (Bose), "Homomya, Pachymya, Ostrea carinata· (?) Lamarck. Exposed . . . . . . . 15.0 PAWPAW: Marl and clay, with thin ironstone seams. The top marly portion contains Enallas,ter sp., H emiaste·r sp., H olaster sp., Epiaster sp., Pecten sub­ alpinus (Bose) and many other calcite fossils. . . . . • . . . . . . . . . . . . . . . . . . 18. 0 Sandstone flag layer. STARFISH ZONE............................... .3 Ironstained reddish impure clay with many pyrite fossils, including: Engon­ oceras sp., Turrilites sp., Hamites tenawa Adkins and Winton, Holaster sp., Ena~laster sp., Hemiaster sp. aff. bexari Clark, Acanthoceras worthense Adkins, Arca< sp., Nucula sp., Mortoniceras worthense Adkins, Schloenbachia sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. 0 WENO: Impure limestone, forms top of first terrace. Marlier beneath, N odosaria . texana Conrad, zone at the base......:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.7 Limesfone at top, forming second terrace, marl beneath. Contains a large fauna, rich in echinoids and pelecypods....................... _ . . . . . 31. 0 Limestone ledge, indurated, fucoidal, Gervilliopsis invaginata (White) zone, Gryphea washitaensis Hill, Pecten subalpinus (Bose), Pinna 'guada­ lupae Bose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 3 There is about 13 feet of fossiliferous W eno marl beneath the creek bed. This is well exposed at the locality 618 (q. v.). SECTION OF THE WENO AND PAWPAW FOHMATIONS FOUR AND ONE-HALF MILES SOUTHEAST OF FORT WORTH, 'l'EXAS, AND JUST NORTH OF THE INTERNATIONAL AND GREAT NORTHERN RAILWAY BRIDGE ACROSS SYCAMORE CREEK MAINSTREET: Feet White massive, in part marly, limestone, with Kingena (?) wacoensis (Roemer), Exogyra arietina Roemer, Turrilites brazoensis Roemer, Ostrea carinata Lamarck ( ? ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 . O PAWPAW: Brown clay, marlier ot the top, with an abundant pyrite fauna at the base, including: Arca sp., Mortoniceras worthense Adkins, Acanthoceras worthense Adkins, Engonoceras sp., Schloenbachia sp., Hamites sp., Turrilites sp., Plicatula sp., Pecten subalpinus (Bose), Enallaster bravo­ensis Bose, E. wenoensis Adkins, Epiaster wenoensis Adkins, and other species •••• • e •• e e. e e o Io o e o o o o o o I I Io•• o o I 0 o o o o o o Io o o o I 0 e e 0 o I I Io 0 o 0 I Weno and Pawpaw Formations 39 WENO: Chalky li:rnestone; contains: Ostrea sp. aff. diluviana, Ostrea cu.rinata (?) Lamarck, Pachymya austinensis Shumard, H omomya sp., Schloenbachia sp. (M.), Pecten subalpinus (Bose), Pecten texanus Roemer, Plicatula sp., N odosaria texana Conrad, and many other species. . . . • . . . . . . . . . . . 13 . 5 Yellow marl with many limestone bands, poorly exposed........ .. .... . ... 36.2 Hard white limestone, fucoid, with Gervilliopsis invaginata............. . .. .5 Brownish yellow marl, about...... . .. .. .. . ........................ .. ... 15.0 SECTION OF PAWPAW AND WENO FORMATIONS EAST OF KATY LAKE AND EAST OF SYCAMORE CREEK, ABOUT THREE AND ONE-HALF MILES SOUTHEAST OF FORT WORTH, TEXAS Section furnished by Gayle Scott Section is from creek bed to upland; direction of section, 92 degrees from magnetic north. MAINSTREET: Feet Weathered· limestone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15. 6 Limestone ledge, with slight terrace above. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. 7 PAWPAW: Terrace, covered with soil and water-soaked, marl base; contains a sandstone ledge two feet below top ............. :. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.4 Red, ironstained, slightly sandy marl, with numerous small pyrite fossils; characteristic weathering of receding Pawpaw hillsides. . . . . . . . . . . . . . . . 12.0 Yellow marl, in part soil-covered overlying the flat narrow terrace formed by top member of W eno limestone .... ~ ...................... .r. . . . . . 3.0 WENO : Hard limestone ledge, p~rtly concealed, about.. . ........................ . 3.2 Disintegrated thin limestone ledges alternating with marl layers of varying thickness, partly concealed by limestone debris and soil. . . . . . . . . . . . . . . . 10. 5 Limestone ledge, impure, yellow, heavily ironstained, indurated ledge, con­taining Pentagonaster texensis Adkins and Winton (rare), and small starfish, indet. (fairly numerous). This ledge forms the base of the abrupt upper Weno terrace, and is easily recognizable in the Fort Worth region. PENTAGONASTER ZONE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 Yellow marl, heavily ironstained, containing thin limestone ledges. NODO­ SARIA TEXANA HORIZON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.0 Disintegrated limestone, capped by a thin limestone ledge. . . . . . . . . . . . . . . . 3. 2 CONCEALED. Interval contains Gervilliopsis Zone . . . . . . . . . . . . . . . . . . . . . 28. 5 ·Heavy limestone ledge, impure, fucoidal, yellow, and slightly less resistant than the one mentioned below. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Blue marl (pipe clay), weathering to gray, fractures on drying into small blocks..... ........ . ..........·. .......................·. . ... . ... . .. 3.5 Heavy limestone ledge, fairly pure, very resistant, containing Pecten texanus, Pecten georgetownensis. In many places forms the bed of Sycamore Creek; _... . .. . .. . .......·....... . ..... . ....... .. . .... ......... .. ... 1.5 Blue marl (pipe clay), gray on weathering, and having a very fine texture 5. 2 40 University of Texas Bulletin DENTON: Top of Gryphea washitaensis conglomerate, in bed of creek........... · . · · · 2.0 Further sections of the Weno formation in Denton, Johnson, and other counties have just been given in the discussion of the Pawpaw formation (q. v.). STRATIGRAPHIC CORRELATION NORTH CENTRAL TEXAS AND SOUTHERN OKLAHOMA The Weno and Pawpaw formations can be traced continuously through these two regions and their correlation is obvious. As has been already noted, the sandstone facies of the Pawpaw formation has been included by Taff in his Bokchito formation. This facies is similar at Gainesville, Den­ison and Bokchito, and in itself affords insufficient differences to be con­sidered as a different formation on the two sides of the Red River. The whole Weno formation is also included in the Bokchito formation of Taff. Taff's tabulation of equivalencies1 makes clear that the Bokchito forma­tion is to be considered equivalent to the undefined upper part of the Georgetown limestone in the Austin quadrangle, but to what formations in North Texas is not clear. However, his Caddo formation is described as having at its top a bed of oyster shells "similar to those occurring below and at the top of the Kiamichi formation" (ibid, p. 6). This is the Den­ton marl and has characteristic Denton fossils, and therefore the base of the Bokchito formation is to be considered as the base of the Weno.2 SOUTH CENTRAL TEXAS . The Weno and Pawpaw formations have been traced with certainty to the Brazos River south of Blum. The regional and facies differences in Central Texas make correlation difficult on account of the smallness of the known Del Rio fauna. It is presumed that the Exogyra arietina zone of the basal Del Rio clay is continuous with that of the Mainstreet limestone north of the Brazos near Blum, and that the Nodosaria texana zone present in West Texas at the top of the Del Rio just beneath the Buda limestone3 but reduced or absent in Central Texas does not correspond to the promi­ nent N odosaria zone found at the top of the Weno and the base of the Paw­ 1Taff: Atoka Folio, p. 6. 2Stephenson (U. S. G. S., Prof. Paper 120-H, pl. XVIII) places the Denton clay member and the Ostrea carinata bed capping it at the base of Taff's Bokchito forma­tion; and also, very curiously, puts the "Gervilliopsis bed" near the base of the Denton clay. 3Bose: Univ. Texas Bull. 1902, p. 19. Weno and Pawpaw Formations paw formations in North Texas. Turrilites brazoensis, also a fossil of very limited vertical range, marks the top of the Georgetown limestone and the base of the Del Rio clay in Central Texas from the Brazos· southwards. The basal Mainstreet then is represented by the uppermost Georgetown in Central Texas, and the Pawpaw if present by strata lying high in the Georgetown, while. the bulk of the lower Del Rio (Exogyra arietina zone) . is Mainstreet and the upper Del Rio is Grayson. WEST TEXAS AND MEXICO West of the southern turning point of the Comanchean outcrops in Bexar County, the Georgetown limestone and the Del Rio clay preserve their in­ dividuality into the Trans-Pecos region. At the type locality of the Del · Rio clay, it is typically developed as a laminated, greeniSh-blue clay with thin instratified arenaceous clay seams, calcareous flags and shell breccia (Exogyra arietina and N o.dosaria texana). In lithology this formation "varies from a clay to an arenaceous thin bedded limestone."1 Here the limestone facies is beginning to appear. It increases in amount south­ wards and in the Mariscal Mountains the bulk of the formation .is lime­ stone. On the other hand, at Cerro de Muleros, Bose's subdivision 6, rep­ resenting Weno and Pawpaw, is a marl with sand and lime, and his sub­ division 7, representing the Mainstreet is sandstone. The lithological va­ riations of the Weno and Pawpaw are summarized on page 27. The Georgetown, like the Buda, is over much of West Texas a fine grained crystalline semi-lithographic limestone, grading northwards into a marlier and sandier near shore phase. The same correlation as in Central Texas (page 40) holds for these strata. The age of subdivision 6 of Qerro de Muleros is delimited by several of its fossils. The following fossils have not been found below this subdi­ vision, rior below the Denton formation in North Texas: Ostrea quadri­ plicata Shumard, Ostrea marcoui Bose. Pinna guadalupae Bose is un­ known below subdivision 6 and below the Weno of North Texas. Enallas­ ter bravoensis Bose, known from subdivisions 5-6, is not known to occur lower than the Denton formation elsewhere. Helicoc1+yptus mexicanus Bose of subdivision 6 is as yet known only from the Pawpaw of North Texas, and the same is true of Placosmilia spp., which are probably iden­ tical with P. bravoensis and P. mexicana. The zone of extreme abundance of Gryphea washitaensis Hill so conspicuous in this subdivision is paral­ leled in North Texas only by that at the top of the Denton formation. iRoberts and Nash: Univ. Texas Bull. 1803, pp. 14-15. University of Texas Bulletin These facts i~dicate that subdivision 6 is equivalent to the Weno and Pawpaw and to part of the Denton formation. The overlying sand, lack­ing ExogYra arietina, contains near its top H emiaster calvini Cla!k and Exogyra whitneyi Bose. The former fossil is upper Washita, Weno to Buda, and the latter is known from the Buda, although from the present record it is: evident that it ranges as low as the Mainstreet formation. It may be of interest to add a list of species described from Cerro de Muleros, which have been found in North Texas. The number cited is that of the corresponding divi­sion at Cerro de Muleros, and the following formation nzcmes refer to the location of the fossil in North Texas. Epiaster aguilerae Bose, 5; basal Fort Worth. Enallaster bravoensis 5, 6, 8; W eno to Grayson. H-0lecty'[YUS limitis 5; Weno to Grayson. Ostrea marcoui 4, 5, 6; W eno to Grayson. Pinna guadalupae 2, 6; basal W eno. Pecten SJJ-balpinus 2, 3, 5, 6, 8, 9; Goodland to Grayson. Pecten irregularis 1, 2; Walnut to Kiamitia. Plicatula subgurgitis 2, 5, 6; Duck Creek to Pawpaw. H elicocryptus mexicanus 6; Pawpaw. Turbo chihuahuensis, La Encantada; Weno. Tylost-Oma chihuahuense 1, 2; Glenrose to Goodland. Schloenbachia trinodosa 5; 6; Duck Creek EUROPE AND 'NORTHERN AFRICA It is unquestionable that the aggregation of Pawpaw pyrite ammonites here described parallels Pervinquiere's Vraconian fauna more closely than it does his Cenomanian fauna. This might mean that the Pawpaw fauna is Vraconian, or that some later (Cenomanian) species are included in his Vraconian fauna; or the Pawpaw fauna may be one which has persisted with little change from its Vraconian ancestors. Scaphites aequalis-like species in Texas are known to range from the Duck Creek marl to at least the Pawpaw clay; in Europe they are of Upper and Lower Cenomanian, Vracoliian, or even Albian age, so that this species decides little; the Paw­paw or the .Duck Creek aequalis may be contemporaneous with the Vra­conian examples. Flickia decides nothing, since the range of the genus is unknown and is extended with each new species discovered. Hamites sim­plex ranges from Aptien to Mid-Cenomanian. Attempts have been made to correlate the Texas Washita division on the basis of Schloenbachia in­ff,ata. This brings us face to face with the question, What is inff,ata? Is it, as sometimes claimed, a Schloenbachia with low, sigmoidal ribs and two tubercles, one umbilical and one marginal; or is it a Mortoniceras, with square volutions and coarse short ribs having three tubercles, an umbilical Weno and Pawpaw Formations and a pair of twinned ventro-marginal ones, as indicated by Pervinquiere? If the latter, there is no Duck Creek species known to me that approaches it as closely as do several Upper Washita species. For only above the base of the Weno do we begin to find fairly large (6-12 inches) coarse straight ribbed square coiled ammonites with an umbilical and a twinned marginal tubercle ; this is the commonest and most characteristic W eno calcite spe­cies, and it abounds in slightly smaller size in the nacreous ironstone _W eno fauna (Plate 3, figure 11). In the Pawpaw clay the same type is abun­dant as small pyritic casts (M. worthense, Plate 1, figures 6-10, 18-19, 26), having extremely short coarse ribs with very prominent twinned marginal tubercles and a narrow square volution. Again in the Mainstreet lime· stone the common calcite species has lower, somewhat sigmoid ribs with twinned marginal tubercles and a rectangular section. Are any of these inflata? If the Vraconian is to be placed in the Weno, which seems pos­sible, the whole Cenomanian will have to lie between the Pawpaw and the base of the Eagleford shales, which is generally claimed to be the base of the Turonian. Again a Duck Creek species similar to Schloenbachia elob­iensis has been noted; but a comparison of Szajnocha's figures and descrip­tion indicate that this species is different from his; its section is much lower, and the shell bears spiral circlets which form Fegular radial rows contain­ing numerous imbricated lips, while in the Texas species (known only as internal casts) there are radial rows of only a few rounded tubercles; in addition, the stratigraphic data given by Szajnocha are inadequate for cor­relation with the Texas strata. A comparison of the Duck Creek limonite fauna with the African Vra­conian yields only _slight results. On the theory that the Pawpaw is Vra­conian, the Duck Creek could scarcely be placed earlier than the Albian, since the Glenrose is with some certainty assigned to the Aptian. But Al­bian species1 are not apparent in the Duck Creek limonite fauna, whose am­monites are preponderantly small species of Schloenbachia and Hamites, with scattering Scaphites sp. aff. aequalis, Desmoceras, etc. Hoplites and other abundant Albian genera are so far unknown. The fauna on the other hand is predominantly Vraconian. This Vraconian aspect appears to end with the Duck Creek limestone or marl, since with the next limonite fauna, that of the Denton marl, there seem to be some species with Cenomanian affinities. Comparison of the Texas Washita faunae with those of Western Europe, examples of which are before me, shows much less resemblance than with the Northern African fauna. Common European species, as Douvilleiceras mammilare, Schloenbachia varians, S. mantelli, and Holas­ter subglobosus have no representatives in the Texas material so far known. On the other hand, the Mainstreet, Grayson and Buda faunae are 1Listed among other places in: Tomitch: Contributions a la Connaissance de l'etage Albien dans le Sud-Est de la France. Le Mans, 1918. University of Texas Bulletin of a higher Cenomanian type, containing for example Codiopsis sp. aff. doma, Tissotia spp., and Acanthoceras spp. ; and Berry. states1 that the pa­kota (Woodbine?) flora is of Turonian age. On the whole then the Pawpaw fauna is placed provisionally as Ceno­manian with much uncertainty as to its exact position. This question will be settled when the rich ammonite faunae of the Lower Washita are crit­ically studied. The Texas Comanchean sea was transgressive or at least not regressive for a long period so that the relatively stat~onary shallow­water conditions may not have encouraged a rapid evolution of these am­monites; whatever the cause, they present notable similarities from the earliest to the latest pyrite faunae known in the Texas Comanchean. · On the theory of persistent and nearly stationary species from Vraconian to Cenomanian time some nearly similar species should be much extended ver­tically in the Lower Washita sediments; further study of the proper ma­rine facies of each stratigraphical level should reveal these and by filling in the great gaps in our paleontological knowledge give a fairly complete fauna! succession. It is hoped that information on the extent of the various marine facies in the Texas Comanchean formations will contribute to this result. PALEONTOLOGY The rich Weno and Pawpaw faunae initiate a new group of species after the considerable paleontological break which occurs at the top of the Den­ton marl. The W eno formation, besides containing characteristic ammon­ites, is notable in its marl facies for an exuberant echino~d fauna, and in its shale facies for a great abundance and variety of distinctive cephalo­pods, pelecypods and gastropods preserved with the original nacreous shell. Certain elements of this nacreous fauna forcibly ren:iind one of the Eocene faunae, with which they have many genera in common. The fossils are perfectly preserved, often with iridescent luster, and the original shell shows the minutest details: in pelecypods, prodissoconch and other embry­onic stages, ligament, and usually the finest features of dentition and ex­ternal ornamentation; in the cephalopods, the original pearly or iridescent shell, and beneath this,, finely preserved sutures etched into the ironstone interior. The Pawpaw formation on the other hand contains a diverse and char­acteristic assemblage of small pyritic ammonites, echinoids, pelecypods, 1Berry: U. S. G. S., Prof. Paper 84, pp. 71, 128 . . Weno and Pawpaw Formations gastropods, corals and other fossils.1 This fauna has close resemblances to that described by Pervinquiere2 from the Vraconian of Tunis and Algeria, a subject that will be considered later. The later Washita seas were transgressing over extensive land areas and a large numerical expansion in the marine fauna occurred, probably in part in the invaded trough already described. In addition, the portion of the ocean bottom which received the mixed clay and sand deposits was probably at a moderate depth and not far offshore, and permitted a wealth and variety of fauna. Note the complexion of life in the Pawpaw seas: swarms of sharks and dogfish; a multitude of bottom-loving crustacea, small crabs and lobsters. echinoids, oysters and scallops; sessile corals and worms; pelagic protozoa; a few large, free-swimming nautili and irides'­cent-shelled ammonites, and a great diversity of small ammonites. 1THE WENO FAUNA Of the large and well preserved W eno fauna only a few species have been mentioned in the literature, as follows : Hill3 listed the following fauna from the North Denison sands (=Weno): Axinea sp. Tapes sp. Nuculaea sp. Turritella sp. Corbula sp. And the following from the Pawpaw shales and the North Denison sands (not separated) : Turritella sp. (predominant) Trigonia emoryi Conrad Corbula sp. Pholo,.lomya postextensa Cragin A~inea sp. Cyprimeria (large sp.) VolseUa sp. A nchura mudgeana White Tapes sp. Leda 2 spp. Cytherea sp. Mactra sp. Tellina sp. Dentalium sp. Avicula sp. Sc<'laria sp. Gervilliopsis, or Gervillea Ostrea quadriplicata Shumard Arca sp. Pecten inconspicuus Cragin Nucula sp. Y oldia microdonta Cragin Ammonites emarginatus Cragin Turritella seriatim-granulosa Roemer Sphenodiscus belviderensis var. Astarte sp. serpentinum Cragin 1Throughout this paper an asterisk (*) preceding the name of a fossil indicates that the fossil has pyrite, limonite or hematite preservation; a double dagger (:j:) indicates · nacreous preservation. 2Pervinquiere: :Etudes de Paleontologie Tunisienne. Paris, 1907. aHm: Bull. Geol. Soc. Amer., 5, 1894., and 21st Ann. Rept., U. S. G. S. pt. 7, p. 277, 1901. 46 University of Texas Bulletin The following species of. the fauna have been described by Cragin = 1 Pecten inconspicuus Tellina subaequalis Pholadomya postextensa Sphenodiscus emaru':natus Corbula crassicistata Engonoceras belviderensis var. serpen- Tapes denisonensis tinum The following species were listed by Stephenson :2 Nucula sp. Cymbophora sp. Ostrea quadriplicata Shumard Turritella sp. Protocardia texana (Conrad) Anchura mudgeana White Cyprimeria sp. Engonoceras serpentinum Cragin Corbula 3 spp. Crustacea An incomplete list of the Weno fossils on hand is given in the accompany­ing table (Table 1) ; many species were omitted for further study. · RANGES OF WENO FOSSILS The ra11ge as given in this table will demonstrate that one of the major paleontological breaks in the Washita division lies at the base of the Weno formation. The contact between the Denton and Weno formations is ap­parently conformable, and many species cross it; but a considerable num­ber of others do not range higher than this contact while another consid­erable group does not range lower. Without speculating as to the origins of the latter group, it may be delimited more clos(3ly in view of a more detailed study. ABBREVIATIONS FOR TABLE OF WENO FOSSILS * Pyrite, limonite or hematite preservation. :j: Nacreous preservation. A Abundant 0 OccasionaJ R Rare S Sand phase SH Shale·phase M Marl phase L Limestone phase u upper part of formation m middle 1 lower 1Cragin: Colo. Coll. Stud., 5, 1894, p. 49. 2Stephenson: U. S. G. S., Prof. Paper 120-H, 1918, p. 141. Weno and Pawpaw Formations 47 601 Pit of Gainesville Brick Company, brickyards one and three-fourths miles south· east of Gainesville, Texas, just east of Rock Creek (branch of Pecan Creek) and just south of the Missouri, · Kansas and Texas railway (Wichita Falls branch). Includes the ironstone ·dump on east rim of pit. Shale facies basally; ironstone and sand facies above. 602 East bank of Sycamore Creek, two and one-half miles southeast of Fort Worth, Texas. Marl facies basally; limestone facies above. 604 Cut of St. Louis and San Francisco railway, three-fourths mile north of Union Station, Denison, Texas. Shale facies basally; ironstone and sand facies above. 605 A branch of Duck Creek, three-fourths mile north of Union Station, Denison, Texas, and just west of locality 604. Shale facies. 606 Exposure in valley just south of St. Louis and San Francisco track, two miles north of Denison, Texas. Shale facies. 611 Waterfall 200 yards south of crossing of International and Great Northern rail­way over Houston and Texas Central railway track near Sycamore Creek, three miles southeast of Fort Worth, Texas. Marl facies. 612 Cliff on northeast bank of Sycamore Creek, 100 yards north of the Houston and Texas Central railway bridge across Sycamore Creek, three miles southeast of Fort Worth, Texas. .Marl facies basally; limestone facies above. 618 Area in valley east of Armstrong Iron Works, South Hemphill street, Fort Worth, Texas, and west of the International and Great Northern railway track. Marl facies basally; limestone facies above. THE PAWPAW FAUNA As already stated, the bulk of this fauna is limonitic, pyritic or hema­titic, but there are in addition some fossils with calcareous preservation. The calcareous fossils are echinoids, pelecypods, a few cephalopods and other miscellaneous fossils. The echinoids of the basal portion of the for­mation are mainly limonitic, but those of the upper, marlier portion over all of the Pawpaw outcrops except in the Red River region, are calcareous mud-filled tests. LIST OF .PAWPAW LOCALITIES 714 One-fourth mile south of the International and Great Northern railway bridge across Sycamore Creek, four and one-half miles southeast of Fort Worth, Texas. Entire thickness of Pawpaw, somewhat overwashed at top; north­eastward facing slope of hillside, and beneath the slope a considerable terrace on the top of the Weno limestone. Clay facies basally; some marl at top. 715 Amphitheater one-half mile northeast of locality 714. Entire thickness of Paw­paw formation exposed. 716 Pit of Cobb Brickyards, one-fourth mile east of Sycamore Creek and three miles southeast of Fort Worth, Texas. 718 Cut of International and Great Northern railway track one-fourth mile south of bridge across Sycamore Creek, four and one-half miles southeast of Fort .i::.. TABLE II. FAUNA OF THE WENO FORMATION ., FORMATION I DIVISIONS LOCALITY IN 601 I OTHER WENO LOCALITIES = 0 ......,., s -;::: OS ., =0 ..... .!! ~ ~ ~ ;::;1 ~ ­~ ., .,... ... 0 0 .!>4 ~.,::s ::s i:l i-:1 :S ... 0 i:: 1: 0r;.. d .s § i:l 0 =., i:: ~ ol ~ p.. ....,., b., =·; ~ =0 ~ ... t!I ol ""::s i:Q -;::: ol ~ e=::s ~ .;..c: r/l ~ =.,, ~ -;::: ol ~ .,::s ii:i .;..c: r/l ...., ~ = t5 ., = .s., = 0 ... ..... ~ s ~ 1': ... &I "" 0 --------------------------------­-texanus Roemer -----------------------------------­t-inconspicuus Cragin ------------------------------­-georgetownensis Kniker ---------------------------­-sp_ --­----­----·----­------­----­--­-----------­----Gryphea washitaensis Hill -------------------------------­Ostrea quadriplicata Shumard ---------------------------­Ostrea carinata ? Lamarck -------------------------------Ostrea marcoui Bose______________________ ----------------Ostrea sp. aff. diluviana Lamarck_________________________ Ostrea sp. (sm!lll, zigzag) --------------------------------Exogyra sp. aff. arietina_____ _____________________________ R R R R 0 0 0 R A R 0 0 ? A 0 A R A A 0 0 0 A·o A R A A 0 A 0 0 0 R R R 0 R R 0 0 0 0 0 0 0 0 0 A R 0 0 R 0 R R 0 R R A A A R R A A A R R A 0 0 R R 0 A A R R A A 0 0 0 ..- 0 0 0 0 R R 0 A A 0 R A A A 0 R R R R 0 R A 0 f:i;:s R.. ~ ~ "d ~ ~ ~ 0 '"i Homomya sp. ------------­-------------------------------Plicatula spp. --------------­_-----­---------------------­:t:Corbula wenoensis _________________---------­_-----­_____ :t-basiniformis --------------------------------------­-Iittoralis -----­_--­---­--­-­------­------­--­------­tNucula w~noensis ---------­---------­_-----------------­:t-nokonis-----------­----~--­-----­-------­-­--­--­--Remondia? acuminata Cragin ---------------------------­+Tapes sp. ----------------------------------------------­tM:eretrix sp. -------------------------------------------­:tCyprimeria washitaensis ---­__ ----­---­----------------­-sp. (large) 0 R 0 R A 0 0 A A 0 R 0 A A 0 -­A 0 R -­0 R A R 0 . -­A 0 0 R 0 -­R R 0 0 0 A A A 0 0­0 R 0 0 R 0 0 A -­0 0 R 0 0 A 0 A R 0 0 0 0 A 0 A 0 0 0 0 A 0 A 0 0 0 A 0 A 0 0 0 A 0 0 0 A 0 A 0 R A 0 ~ f:i ~ "'°·0 ~ :tLeda n. sp. -----------------------------­--------------­:tYoldia n. sp. -------------------------------------------­:tProtocardia sp. aff. multistriata__________________________ -vaughani Shattuck -------------------------------­-sp. aff. texana ----------------------------------·-­ 0 A R R 0 R A 0 0 R 0 0 0 R A A 0 R R R R R 0 0 0 R A A A 0 t-sp. ------------------------------------------------Pholadomya shattucki Bose ------------------------------­Trigonia clavigera Cragin--------------------------------­Barbatia simondsi ? WhitneY----------------------------­ R ·­R R' 0 A 0 -­R R R R 0 A 0 0 ' 0 0 0 R R R A 0 0 0 ~ ~ Barbatia sp. ----­--------------------­­Ostrea perversa Cragin ------­-­-­-----­-­----------­-. -­Lima sp. aft. wacoensis­-----­----­--­-­------­----·--· ­--A.rca Hp. ·-----------------------­-----,------------------Pachymya austinensis --11p. aft. austinensis Cardium sp. aft. congestum----­-----------­-----------­Cucullea sp. ----------------------­---­--­*Venericardia wenoensis --------­--·­---__ Isocardia sp. ---­------------------­----­-Lima sp. (large) ----------------­--­--------------­----­A.nomia -----­--­ 0 0 0 -­-­R R R 0 0 0 0 -­R A 0 A. 0 R -­0 -­---­-­-­R -­R -­ -­-­-­-­0 0 -­R 0 0 -­ -­-­-­-­0 0 -­R -­0 -­-­ -­-­-­-­-­-­-­-­-­-­-­-­ R -­-­-­-­-­-­-­A. 0 -­0 -­-­-­-­-­-­R -­0 -­0 0 -­-­-­-­-­-­-­-­-­-­0 0 -­-­-­-­-­-­-­-­-­-­-­ R -­-­-­-­-­R -­-­-­-­ R -­-­-­-­-­-­-­-­-­ -­-­-­-­0 -­---­-­-­-­ -­-­-­-­-­-­-­-­-­-­-­ -­-­-­-­-­-­-­-­-­-­-­ -­-­-­-­0 -­-­-­-­-­0 -­---­-­0 0 -­-­---­0 -­-­0 0 0 0 -­R A 0 0 -­ 01 0 BRYOZOA.: Eschara ? A.ctinopora sp. -------------------,­··----------------­---­? sp. A. -­ A. 0 • -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ A. 0 CORA.LS: Trochosmilia ? Pacosmilia sp. 0 0 0 -­ -­-­ -­-­ -­-­ -­0 -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ 0 -­ 0 -­ 0 -­ -­-­ ~ ;s.,..,, ~ ANNELIDA: Serpula sp.1 Serpula sp.2 PROTOZOA.: 0 A. R A. 0 0 -­ -­-­ -­-­ -­-­ -­-­ -­-- -­-­ -­-­ -­-­ -­-­ A. -­ A. -­ A. ·­ A. -­ A -­ A. 0 -­-­ ~ "'i ~ ""·~ ~ Nodosaria texana Conrad_ A. 0 -­ -­ -­ -­ -­ -­ -­ -­ -­ 0 -­ -­ -­ 0 0 0 <::>._ FISHES: Odontus appendiculatus ----­______ ___ --­--------­________ Oxyrhina mantelli -------­-------------­----­~ ---------­_ A. 0 A. A -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-­ -­-- -­-­ -­-­ -­-- -­-­ -­-­ ~ (I:) ~ ~ ~ O::I ~ .,.....,.... (I:) ~ ~· Weno and Pawpaw Formations 51 Worth, Texas, and one-eighth mile east of locality 714. Upper part of Paw-paw formation, partly marl, overlain by Main street limestone. • 719 Crowley Road, one mile south of the Baptist Seminary, and four, and one-half miles south of Fort Worth, Texas. Westward facing cut in hillside, exposing poorly most of the Pawpaw -formation. 720 Rim of Weno escarpment one mile southeast of Riovista, Texas, and midway between the Riovista-W aco pike and the Santa Fe track. The Pawpaw, simi­larly exposed between the Mainstreet and W eno limestones, continues west­ward to the next locality. 721 East-west escarpment just east of Riovista-W aco road, one mile south of Riovista, Johnson County, Texas. The Pawpaw is much thinned, and is transitional between clay and marl facies. 722 Cut of Missouri, Kansas and Texas railway (Wichita Falls branch) at north end of pit of the Gainesville Brick Company, one and three-fourths milee southeast of Gainesville, Texas. 723 Westward facing hillside lying under Mainstreet upland on west side of Mans­field Road, halfway between Glen Garden Country Club and Sycamore Creek, three miles southeast of Fort Worth, Texas. 724 Hillside on north side of east-west road, three miles southeast of Haslet, Tarrant County, Texas. Whole thickness of Pawpaw. FAUNA OF THE PAWPAW FORMATION S: Sand facies ; C : Clay facies ; M : Marl facies ; L : Limestone facies ; A: Abundant ; 0: Occasional ; R: Rare; I: lower third of Pawpaw foration; m: middle portion of Pawpaw formation ; u: upper portion of Pawpaw formation ; * : Pyrite or Iimonite preservation ; · t : nacreous preservation. SPECIES LOCALITY: 716 714 715 718 719 723 724 722 720 721 c c c M c c cs s M M CEPHALOPODS: Shumard___ ____ _______ Nautilus texanus R R R 0 R R R Nautilus sp. R R 0 R dispar_______________ *Stoliczkaia sp. aff. R R Adkins RI *Flickia boesei -----------------­ • Acanthoceras worthense Adkins --------A A 0 0 A 0 • Acanthoceras BP.· aff. suzannae A A Winton____ *Hamites tenawa Adkins and R R *Hamites sp. atf. arrnatus----------------R R Winton______ 01 0 0 A R*Scaphites hilli Adkins andworthensis_______ ______ *Scaphites sp. atf. 01 0 *Baculites comanchensis Adkins R 0 *Turrilites worthensis Adkins and Winton A A A 0 A R Adkins !!-nd Winton____ 0 A 0 A •Turrilites sp. B. *Turrilites sp. A A A A A 0 tSchloenbachia wintoni Adkins ----------R R R *Mortoniceras sp. 0 0 -~--------------------­ *Mortoniceras worthense Adkins --------0 A 0 0 A R *Engonoceras sp. A A A 0 A 0 ________ R · R tEngonoceras serpentinum Cragin R *Puzosia sp. ----------------------------R •Lytoceras sp. aff. maruL---------------R R *Hamulina worthensis Adkir:s-------------.-R ASTEROIDEA: *Pentaceros americanus Adkins ----------RI • Metopaster hortensae Adkins and Winton RI R • Comptonia wintoni Adkins --------------RI • sp. indet. RI OPHIUROIDEA: Ophioglypha sp. R University of Texas Bulletin SPECIES LOCALITY: 716 714 715 718 719 723 724 722 720 ECHINQIDEA: *Goniophorus sp. ----------------------­R *Peltastes sp•. --------------------------­R Enallaster bravoensis Bose --------------0 0 0 0 0 0 Enallaster sp. aff. texanus_______________ 0 0 0 0 0 Enallaster riovistae Adkins --------------· 0 A Hemiaster wenoensis Adkins ------------­Hemiaster calvini Clark ----------------0 0 0 0 0 0 Epiaster wenoensis Adkins -------------0 0 0 0 0 Epiaster subobesus Adkins --------------0 0 0 0 0 0 0 Holaster sp. ----------------------------0 *Holaster BP---------------------------­ R 0 Holectypus limitis Bose -----------------0 0 0 0 0 0 R A *Goniopygus sp. ----------·---------------R CRUSTACEA: crabs, indet. ---------------------------­R R lobsters, indet. --------------------------R R CORALS: *Placosmilia spp. ----------------------­R R *Trochosmilia sp. ----------------------­R R corals, indet. ---------------------------R PROTOZOA: *Nodosaria texana Conrad_______________ 0 A 0 0 0 0 PELECYPODS: *Arca washitaensis Adkins -------------A A A A A R Ostrea carinata ( ?) Lamarck___________ _ 0 Ostrea quadriplicata Shumard ----------­0 0 Gryphea washitaensis Hi!L______________ 0 0 0 0 0 0 0 0 Remondia ( ?) acuminata (Cragin) -----R R R R Plicatula spp. --------------------------A A A A A A A A Pecten subalpinus (Bose) ---------------R R R 0 0 Nucula sp. -----------------------------0 0 0 0 0 0 0 R T.eda sp. --------------------------------0 A A 0 0 Lima sp. -------------------------------0 GASTROPODS: Helicocryptus mexicanus Bose ----------­R •Turritella sp. --------------------------0 R .o 0 R *Turbo sp. -----------------------------0 0 R *Cinulia sp. ----------------------------R R R R *Nerinea sp. ---------------------------0 R 0 R VERTEBRATES: sp. indet. (shark?, head bones)----------.R R sp. (Odontus appendiculatus ?) ----------A A A 0 0 A 0 sp. indet. (teeth) ----------------------A A A A 0 A 0 sp. indet. (vertebrae) ------------------A A A A A 0 PARALLELS BETWEEN UPPER WASHITA AND LOWER WASHITA ECHINOIDS LOWER WASHITA UPPER WASHITA (below Weno formation) (Weno and higher formations) Holectypus planatus Roemer H. limitis Bose E. bravoensis Bose Enallaster texanus Roemer E. riovistae Adkins E. wenoensis Adkins E. sp. aff. texanus Roemer Hemiaster whitei Clark and E. eJegans Shumard JI. calvjni Clar}\ 721 0 0 A 0 0 0 0 0 0 Weno and Pawpaw Formations Epiaster aguilerae Bose E . wenoensis Adkins Holaster simplex Shumard H. sp. Cyphosoma texana Roemer C. volanum Cragin Salenia mexicana Schlueter and S. texana S. volana Whitney Credner Goniopygus sp. G. budaensis Whitney Goniophorus sp. 1 G. sp. 2. COMPARISON OF PYRITE FAUNA TEXAS It h-a.s been pointed out1 that the North Texas Comanchean system con­tains a series of alternate lime and marl (or clay) formations, some of which contain conspicuous pyrite and limonite faunae; these are (1) The Kiamitia formation; (2) The Duck Creek marl; ( 3) The Denton marl ; (4) The Pawpaw clay; (5) The Grayson formation; ( 6) The Del Rio clay. Many pyrite and limonite species are common to these six formations, and still others have more restricted vertical ranges and are confined to limited levels within a single formation. In general it may be said that these fossils are of distinct species from those otherwise preserved in the same f orniation; that they are rare in the intervening formations, and that the complexion of the limori.ite faunae is different from that of the other fauna! components of the formations in question. In addition there seem to be certain limonite species in the various intervening limestone f orma­tions, especially in the Fort Worth and W eno limestones. To assist in de­termining the age and correlation of these formations the following pro.., visional fossil lists are given. The list for the Pawpaw formation will be found on page 51. The rather regular alternation of marl (or clay) and lime formations .in the North Texas section suggests some form of cyclic deposition, in which the same marine conditions were many times repeated, and this inference is equally strong for the contained pyrite faunae, when it is found that they occur prevailingly in the alternate, clay, formations. This I Winton and Adkins: The Geology of Tarrant County, Univ. Texas Bull. 1931. 1920. • 54 University of Texas Bulletin does not imply that in certain formations no pyrite faunae ~ill ~e foun?; they existed somewhere during the whole Washita at least, and likely will be found in the clay facies of each formation, just as representatives of the Mainstreet pyrite fauna have been found in the clay facies (Del Rio) of Central Texas, though apparently absent in the limestone of North Texas. It is certain that exuberant pyrite faunae are associated with clay facies; and accordingly the greatest abundance of pyrite fossils in the Kiamitia is in southern Tarrant and Johnson counties; Denton formation, Denison to northern Tarrant County; Pawpaw formation, Tarrant County; Main­street formation, McLennan County and southward; middle Grayson form­ation, Denton County. In each instance the lithology of the region men­tioned is largely of the clay facies. These facts suggest recurrent similar conditions which favored the spread of pyrite faunae. At a given loca:lity this recurrence might be many times repeated; and such pyrite zones are still being discovered at new stratigraphic levels. What these conditions and their causes were will not be discussed here. They resulted in each zone in a highly characteristic pyrite and limonite fossil association, which is as follows: Arca washitaensis, Engonoceras sp., Scaphites spp., Tur­rilites spp., Hamites spp., Cinulia sp., Nerinea sp., Lunatia sp., Turritella sp., pyritic starfishes, and abundant small, non-pyritic crustacea, especially crabs. KIAMITIA CLAY FAUNA 'fhe marl facies of the Kiamitia formation extends from Primrose. southwest of Fort Worth, to a point between Gainesville and Fink, o~ the Red River. The clay facies extend from near Primrose to at least the Brazos River; it is found throughout Johnson County, and on Cedar Creek near Blum is a reddish clay 19 feet thick. With the advent of the clay facies the shell conglomerates of the northern section disappear and a pyrite fauna similar to that of the Duck Creek marl appears. This little investigated fauna contains Arca sp., and other small pyritic and limonitic pelecypods and gastropods. DUCK CREEK MARL FAUNA This fauna is notable for its large number of small pyritic and l' _ 't' t d imo m ic gas ropo s and pelecypods. Such genera as Cerithium c· i · T · ll , inu w, urrite a, Turbo, Lunatia, Arca, Nucula and Corbula are highly ch _ acteristic of the lower Washita pyrite zones. Equally characteristica~E • Weno and Pawpaw Formations the exceptional variety of gerontic ammonites, especially Hamites; Scaph­ites, Schloenbachia, Desmoceras and other genera are also prominent in the fauna. DUCK CREEK .LIMONITE AND PYRITE FOSSILS *Scaphites worthensis Adkins and Winton. *Scaphites sp. aft'. worthensis. *Engonoceras sp. · Hamites tanima Adkins and Winton. *Hamites sp~. *Crioceras ( ?) sp. *Schloenbachia sp. *Neolobites (?) sp . • *Arca sp. *Nucula sp. *Turbo sp. *Lunatia sp. *Cerithium sp. *Nerinea sp. aft'. pellucida Cragin *Cinulia sp. *Anchura sp. *Turritella sp. *Nerfnea sp. *Placosmilia sp. • DENTON CLAY FAUNA The clay facies of the Denton formation extends from northern Tar­rant County (Blue Mound, near Haslet) to beyond Denison. It is char­acterized by a great diversity of small pyrite and limonite ammonites, some of them nacreous, and by many small crustacea, mainly small pyritic crabs. The ammonites seem more abundant southwards than on the Red River and the crustacea the reverse. FAUNA OF THE DENTON FORMATION * Limonite or pyrite species. U Upper. L Lower. *Acanthoceras sp. aft'. aumalense Coquand *Engonoceras sp. *Mortoniceras sp. University of Texas Bulletin *Schloenbachia sp. *Acanthoceras (?) sp. *Turrilites sp. ( ?) *Baculites ( ?) sp. Ophioglypha texana Clark *Starfish sp. (ray) *Goniophorus ( ?) sp. 2 specimens, one with the shell . . Leiocidaris sp. (spine and plate). Leiocidaris hemigranosus Shumard. Hemiaster sp. (plate). Hoploparia sp. Cambarus (?) sp. (like sp. in Gainesville brickyards Weno). Crabs 9 spp. Ostrea quadriplicata Roemer. Ostrea carinata Lamarck. Gryphea washitaensis Hill. Ostrea sp. (small zigzag). Stearnsia robbinsi White (?) . Gervilliopsis invaginata White ( ?) Trigonia emoryi Conrad. Plicatula dentonensis ( ?) Cragin. *Arca sp. Anomia sp. Plicatula spp. *N:ucula sp. *Cardium sp. *Leda sp. *Corbula sp. Pecten sp. aff. inconspicuu:& Cragin. Crania sp. Dentalium sp. ?Porocystis-like masses. *Natica sp. *Cinulia sp. Fish teeth, vertebrae, skin, plates. GRAYSON FAUNA The pyrite and limonite fauna so far discovered in the Grayson forma­tion is confined to the middle clay member of the formation in North Texas, and includes diverse ammonites, gastropods and pelecypods, as listed below. However, the pyrite fauna of the middle Del Rio clay which occurs in McLennan County and southward is of Grayson age, • Weno and Pawpaw Formations and contaiiis some identical species. This latter fauna is well developed on the South Bosque River, five miles west of Waco and includes Turrilites bosquensis Adkins, Flickia ( ?) bosquensis Adkins, Acanthoceras 'Worth· ense Adkins, Schloenbachia spp. and other common Grayson and Pawpaw pyrite species. It is notable that the preservation of this fauna is almost exclusively pyritic. FAUNA OF THE GRAYSON· MARL * Pyrite or limonite species. (C) Cidarid zone. (Co) Coral zone. U Upper member. M Middle member. L Basal member. CEPHALOPODS: Turrilites sp. (medium size) (M). *Turrilites sp. aff. worthensis A and W. *Turrilites spp. (M). *Turrilites sp. (whiplash) (M). *ammonite aff. Flickia (small, keelless) (M). *Hamites 3 spp. (M). . Acanthoceras ? sp. (Denison, WSA). Acanthoceras spp. Engonoceras spp. (L). *Schloenbachia spp. ECHINODERMS: Hemiaster calvini Clark. starfish sp. Goniophorus (?) sp. cidarid spines 3 spp. (C). Cyphosoma volanum (?) Cragin. Enallaster texanus (?) Roemer. Enallaster sp. aff. traski (?) Whitney. Enallaster sp. aff. bravoensis Bose (?). CORALS: *Placosmilia (?) sp. (Co). GASTROPODS: Cerithium sp. Turritella marnochi (?) White. Turritella sp. Cinulia pelletti Whitney. *Gyrodes (?). *Turbo sp. *Turritella sp. (sharp spired) M. Uni-versity of Texas Bulletin PELECYPODS: Gryphea mucronata Gabb. Gryphea sp. aff. corrugata Say. Exogyra sp. aff. columbae Sowerby (L) . Exogyra n. sp. (Denison, M). . Exogyra sp. aff. texana ( U, under Buda limestone, Bosque River, W of Waco)· Pecten texanus Roemer. Pecten subalpinus Bose, *Arca sp. Ostrea sp. aff. subovata Shumard. Lima sp. (elongate). Lima sp. (quadrate). Lima sp. aff. wacoensis Roemer. Ostrea sp. (saucer). Anomia sp. Plicatula spp. Protocardia texana (?) Conrad. Pholadomya shattucki Bose. Tapes sp. Inoceramus sp. M. Corbula ( ?) sp. Trigonia sp. Cyprimeria sp. (small). Cyprimeria sp. aff. crassa Meek. *Nucula sp. *Crassatella (?) sp. ("Remondia"). *Barbatia sp. Trigonia sp. (large). *Isocardia sp. Shark teeth, vertebrae, bones. DEL RIO CLAY FAUNA The Del Rio limonite fauna is very widespread in Texas, having been found at Waco, South Bosque, Austin, Quihi (Medina County), Del Rio, Terlingua, and the Solitario. In McLenna-n County at the base of the Del Rio clay, which corresponds to the middle of the Mainstreet limestone, an extensive pyrite and limonite fauna occurs, including the following: *Exogyra arietina Roemer. *Turritella sp. *Cerithium sp. *Turrilites spp. *Schloenbachia sp. Weno and Pawpaw Formations *Nerinea sp. Lunatia sp. *Natica sp. Goniophorus sp. Pecten subalpinus Bose. Turrilites brazoensis Roemer. The Del Rio pyrite fauna corresponding to the base of the Grayson formation of North Texas has already been noted; it includes: *Turrilites bosquensis Adkins. *Flickia (?) bosquensis Adkins, *Acanthoce~as worthense Adkins. *Schloenbachiao sp. Exogyra arietina Roemer. Gryphea mucronata Gabb. Gryphea sp. Pecten subalpinus (Bose) . The first named limonite fauna with an extensive calcite microfauna immediately overlies the Georgetown limestone and is of middle Main­street age. It is seen at South Bosque, and will probably be discovered at many places in Central Texas. Liddle states that the Del Rio clay throughout Medina County, contains great amounts of dark brown limonitic fragments and fossils. 1 Good localities are a small Del Rio inlier four miles slightly west of north of Quihi on the Bandera road, and the main area of exposure just north of the inlier. These localities contain limonitic gastropods, *Turrilites, *Sca­phites, small ammonites, and loose *Nodosaria. At Loma de la Cruz and other localities in the Del Rio clay lowland two miles south and southeast of Del Rio, the basal clay contains limonitic *Schloenbachia sp., *Hamites sp., *Scaphites sp., *Turrilites (two species), *sp. aff. Flickia ( ?) bosquensis Adkins; *Pyrina or Cassidulus sp., cidarid sp., *Leda, (two species), *Nucula sp., *Arca sp. *Plicatula sp.; *Nerinea sp. (abundant), *Cerithium spp. and other fossils. Along the base of the Reed Plateau, Terlingua, the basal Del Rio clay contains abundant brown limonite fossils, the great majority of which are various species of Turrilites. The fauna includes: *Noclosari.a texana Conrad, *T~.trrilites (three species), *Acanthoceras sp., *Schloenbachia sp.; *Nucula sp. · 1Liddle, The Geology and Mineral Resources of Medina County, Univ. Texas Bull. (in press). University of Texas Bulletin The Del Rio clay surrounding the Solitario Uplift contains· a rich assort-· ment of brown limonitic fossils, including *Engonoceras sp., *Turrilites (two species), *Turritella sp., gastropods, *Nucula sp., *Tapes sp., *Nodo­sµ,ria texana Conrad, and other fossils. It may be mentioned that these limonite faunae in Texas are not confined to the Comanchean, since al rich fauna was found in the Terlingua beds (Taylor marl equivalent) about five miles north of the crossing of the Alpine-Terlingua road through Terlingua Creek, Brewster County, Texas. This fauna includes: *Turrilites sp., *Baculites sp., *Ptychoceras sp., *Desrnoceras sp., *Trochosrnilia sp., *Lingula sp., *Lunatia sp., *Natica sp., *N erinea sp., numerous other gastropods, and fish teeth and vertebrae. Bose1 found a rich Vraconian fauna in limestone blocks covering small hills just west of Camacho, Zacatecas, between this station and the Trin­idad mine, and west of Opal, Zacatecas, int the core of an anticlinal hill consisting of thin-bedded limestone with lenses and concretions of chert. These fossils are mainly silicified, but ar~ cited here on account of their striking resemblances to the pyrite fossils described in this paper. The fauna includes typical Vraconian genera, as Phylloceras, Lytoceras, Macro­scaphites, Harnites, Hamulina, PtychoceraS:, Diptychocems, Anisoceras, Turrilites, Baculites, Desrnoceras, Acanthoceras, Ancycloceras, Toxoceras, Crioceras, Scaphites, Schloenbachia, Brancoceras and Exogyra. SUMMARY OF PYRITE FAUNAE The Washita marl and clay faunae contain distinctive assemblages of ammonites, crustacea, starfishes, echinoids, gastropods, pelecypods, corals, and other fossils. The crustacea are preserved partly with the original integument and partly with limonite ·replacement. The other fossils are in part calcitic, but mainly limonite and hematite pseudomorphs and casts of the interior of the original shell. Ammonites: These are very distinctive for each fauna. Species of Schloenbachia abound in each marl and clay formation. Acanthoceras is found in the Denton, Pawpaw and Grayson faunae, but not in the Duck Creek. Hamites are abundant in the Duck Creek marl and present in the other formations. Turrilites abounds in the Pawpaw and is not known with certainty below it. Flickia, Hamulina, Baculites and Puzosia are known only from the Pawpaw clay. 1Bose, On some new Cretaceous Faunas from Mexico, Univ. Texas Bull. (in press) . Weno and Pawpaw Formations 61 TABULATION OF KNOWN AMMONITES OF THE WASHITA PYRITE AND LIMONITE FAUNAE Number of Known Species in: Duck Creek Denton Pawpaw Grayson Del Rio Species marl marl clay marl clay Hamites ... .. ..... .. .. 10 1 3 3 Turrilites ... .......... . 1? 10 4 1 Acanthoceras ......... . 2 2 1 1 Scaphites ... ..... ..... 2 2 Flickia ...... ...... .... 1 1? Baculites ....... ....... 1 Schloenbachia .. ... .... 3 1 2 2 1 Mortoniceras ... ... ... . 1 2 Puzosia .. ......... .... 1 Hamulina... . . . . .. .. .... 1 Engonoceras .. ... ..... 1 1 3 1 Crioceras (?) ..... .... 1 Neolobites ( ?) ..·.... ... 1 ECHINODERMS: TABULATION OF THE KNOWN ECHINODERMATA OF THE WASHITA LIMONITE FAUNAE Number of Known Species in: Duck Creek Denton .Pawpaw Grayson Del Rio Species marl marl clay marl clay ASTEROIDEA: .M:etopaster ......... . 1 Comptonia .. . ... . .. . 1 Pentaceros .. . ...... . 1 genus, indeterminate.. 1 2 1 OPHIUROIDEA: Ophioglypha ....... . 1 ECHINOIDEA1: Holaster ..... .. . . .. . 1 2 1 Hemiaster ......... . 2 1? 2 2 Stenonia ........... . 1 Epiaster ..... . ... . . . 1 Enallaster ..... . .. . . 1 3 3 Goniophorus . . . . .... . 1 1 1 1? 1 _G~niopygus ...... .. . 1 Leiocidaris . . .... . .. . 1 Salenia ........... . . 1 cidarid spines . ... .. . 2 3 1Most of these have calcitic preservation. University of Texas Bulletin Of these echinoderms the starfishes and brittle stars have so far been found only in the upper formations, Denton and above. The echinoids also seem more abundant and varied in the Upper Washita; Enallaster particularly shows a development of several species in the Weno and Pawpaw formations. Stenon'ia supernus (Cragin) is known only from the Grayson marl. Among the small echinoids, Regularia, especially ' Salenidae, predominate. The Salenidae have a wide distribution and their various species seem reliable as horizon markers. CRUSTACEA: There is a great variety of crabs belonging to many different genera. Of the lobsters a small species of H oploparia is abundant in the Denton marl. Segments of appendages abound in these four formations; claws are found in the Duck Creek and Pawpaw and rarely in the intervening formations. These crustacea are for the most part calcareous and ex­cellently preserved. In addition there are known in the Texas Coman­chean, from the Goodland indeterminate limb segments; from the Duck Creek limestone Callianassa sp. claws; from the Fort Worth limestone a lobster related to Homarus (Dr. Shuler) ; and from the Weno, two lob­sters and an indeterminate claw. A crab and a lobster claw have been reported from the Buda. TABULATION OF KNOWN CRUSTACEA OF THE WASHITA -PYRITE AND LIMONITE FAUNAE Duck Creek Denton Pawpaw Grayson Species mar] marl clay marl ASTACURA: Cambarus ? : . ...... .... ......... . 1 Hoploparia ............. .. ....... . 1 1 appendages, indet. . . .. . ..... . . .. . . 3 species, indet.... . ..... . .. . . . ... . . . 4 ANOMURA: Callianassa ..... ....... ... ..... .. 1 BRACHYURA: species indet. 9 2 PELECYPODA: The Duck Creek limonite fauna is marked by the relative poverty of pelecypods and the. relative abundance of gastropods. A small species of Arca, abundant m the Pawpaw also occurs in the other formations. Weno and Pawpaw Formations 63 The Pawpaw and Grayson each has a considerable assemblage of small pyritic and limonitic pelecypod casts. TABULATION OF KNOWN PYRITE OR LIMONITE PELECYPODS IN THE WASHITA PYRITE FAUNAE Duck Creek Denton Pawpaw Grayson Species mar] marl clay marl •Arca .. . . . .. . , ..... . ............. . 1 1 1 1 •Nucula ... ... .... . ... ·. .. ..... . . . . . 1 1 1 1 *Leda ............ · · · · · · · · · · · · · · · · · 1 1 •corbula . .. . ..... . . . ....... . ..... . . 1 1 •Plicatula ..... ................ .... . 1 2 2 1 *Barbatia .... . .... . .. ... ..... . . . .. . 1 * Isocardia ( ? ) . . .. · . . . . . . . . . . . . . . . . . 1 *Remondia (?) ..... . ... . .......... . 1 1 •Lima ....... ............. .. ... . .. . . l 1 2 1 GASTROPODA: As may be seen in the following table, a fauna of small gastropods is a feature of the pyrite and limonite fossils in these four formations. In the Duck Creek marl these small limonite gastropods are the most con­spicuous element of the fauna. TABULATION OF WASHITA LIMONITE AND PYRITE GASTROPODS Duck Creek Denton Pawpaw Grayson· Species marl marl clay marl *Natica 1 1 1 1 •cinulia ....... ........... ........ . 1 1 1 1 *Cerithium .... ·.... . .. .. .. . .. . .. .. . 1 1 *Turritdla .......... ............ .. . 1 1 2 *Gyrodes........... .. ..... ....... .. . 1 1 •Turbo . . ... . .......... . ... .. ..... . 1 1 1 ~Lunatia 2 1 *Nerinea .. .. ;. .... .. .. .... • .... .. .. . 2 1 "'Anchura 1 OTHER COMPONENTS: Small corals (Trochosmilia, Placosmilia) occur in the Duck Creek and Pawpaw formations, and probably in the Denton and Grayson. There is a notable abundance of small sharks (Lamna, Oxyrhina, Ptychodus) in the Pawpaw, where teeth, vertebrae, plates, skin and brth limestone. LOCALITY: Subdivision 5 of Cerro de Muleros; Individual 1, one-half mile east of Texas Christian University, Fort Worth, Texa.s, locality 406. Individual 2, one-half mile southeast of Mt. Olivet Cemetery, Fort Worth, Texas, lower 10 feet of Fort Worth limestone. EPIASiER SUBOBESUS n~ sp. Pl. 11, fig. 3 MEASUREMENTS : Length, 89 mm. ; Width, 78 mm. ; Height, 52 mm. HORIZON: Top five feet of Weno formation, marl facies; Pawpaw formation, marl f acies. TYPE LOCALITY: 720, top of Weno limestone, one mile southeast of Riovista, Texas. DESCRIPTION: Test rotund, elevated, tapering posteriorly to a very narrow tall truncation sloping forwards at the bottom in the top of which the very small periproct is located. Contour same as E. wenoensis. except more prolonged posteriorly; form straighter sided, much more elevated than that species, apical system proportionately farther forward. Base nearly flat, slightly raised on the posterior mid-line, but much less than in E. wenoensis, excavated for the peristome. Ambulacra straight, arranged as in E. wenoensis, inter-ambulacral areas notably more elevated. Un­paired ambulacrum with about 60 similar slit-like pore pairs obliquely set. Antero-laterals very long, with 90 or more pore pairs in each zone; all pores equal and similar; postero-laterals with 80 or more por-e pairs equal similar slits. Peristome medium, transversely oval, 6.5x6.0 mm.; pe;iproct extremely small, circular, 3.5 mm. diameter, much smaller and situated relatively lower than in E. wenoensis. The description applies to the type individual. This species might be taken as an old individual of E. weno­ensis, but this is pr.ecluded by the differences cited above. The species having this characteristic size and form, is common in North Texas. Weno and Pawpaw Formatiom ENALLASTER The genus Enallaster ranges from the Neocomian to the Turonian, but is especially abundant in the subtropical Cenomanian seas, where its great development and exuberance of closely related species constitute a special and complicated problem. The littoral deposits of the Mediterranean and the Texas regions contain a sequence of poorly defined Enallasters, in which the separate species are probably closely restricted in vertical range and on careful study will prove to have great stratigraphic value; the two areas mentioned have closely similar species. Enallaster differs from Howster and Stenonia in having the ambulacral pores sunk in ambulacral grooves instead of being flush with the surface; it differs from H emiaster and Epiaster in the exceptional depth of the · anterior unpaired ambulacral groove and in the arrangement and length of the pore zones of the unpaired ambulacrum whose pore pairs are of alternate sizes instead of equal. Enallastets are of very diverse form, one group being flattened and short-ovoid, one group depressed but very elongate, and a third group rather tall and of elliptical contour. As defined by Cotteau, Enalwster contains only species in which the anterior unpaired ambulacrum contains alternate long and short pore pairs. Hemiaster differs from Enallaster in having the pore pairs of the unpaired ambulacrum slit-like and similar, and the pores of a pair sepa­rated by a rounded tubercle. The Texas species of H emiaster are diverse and fall into two general groups. A. Postero-laterals very short, biconvex, apical system placed far back on test; anterior row of antero-laterals with pairs of minute circular pores, form low, with long anterior slope. . H. longisulcus (Adkins and Winton) 1 • H. riovistae Adkins. B. Postero-laterals long, more nearly straight, apical system nearly ·central; anterior zone of antero-laierals with larger slit-like pores; form more elevated and inflated. H. calvini Clark. H. elegans Shumard. H. whitei Clark. H. sp. (Goodland limestone). H. comanchei Clark. 1Erroneously referred to the genus Enallaster. Univers-ity of Texas Bulletin ENALLASTER WENOENSIS n. sp. Pl. 5, figs. 3 I MEASUREMENTS: (Type) 25.0 mm. Length ____________ ------------------------------­ 23.4 mm. Breadth ----------------------------------------­ 14.3 mm. Height ------------------------------------­Length from apical system to posterior border________ 9.0 mm. HORIZON: Upper five feet of Weno formation, marl facies. Base of Weno: base of Pawpaw clay. LOCALITY: 720 (type locality), one mile southeast of Riovista, Texas, and one-half mile east of the Waco road; 602, 618, near Fort Worth, Texas. DESCRIPTION-TEST: Test oval in general outline, broadest point anterior to the center, less elongate and more abruptly truncated poster­iorly than H. riovistae ri. sp.: anterior notch more pronounced than in that species and anterior groove shorter. Apical system located a little less than two-thirds the way back on the mid-line. The outline of the test seen from above is ovate, with angulations; the anterior corners of the test are broadly round to the notch of the anterior sulcus, the posterior corners on the ambitus are abruptly rounded to the excavated periproct area. Oval surface inflated medially, the most prominent point being on the mid-line about two-thirds the way from the anterior end of the test. Aborally the highest point of the test is on the carina midway between the posterior ends of the short postero-lateral ambulacra and the test slopes gently anteriorly from this point, as in E. bravoensis Bose, and H. riovistae. Anterior unpaired ambulacrum sunk in the deep anterior sulcus which is relatively shorter and narrower than that of H. riovistae n. sp. Each zone has about 31 pairs of ambulacral pores. About the first twelve pore pairs are short, similar and equal except that they increase in ­size from the apical system anteriorly. They have each two equal short slits separated by a tubercle. Next come five pore pairs, three long and two short, alternating. Next come two groups of two short pairs each, alternating with long pairs. Thereafter anteriorly the pores are short and similar. Throughout this series in all the short pairs, the pores of a pair are separated by a tubercle, which in all the long pairs is lacking. The type agrees with this description. The narrow ambulacral plates reaching the mid-line, have each two transverse rows of variable sized tubercles, irregularly arranged. Weno and Pawpaw J?ormations Anterolateral ambulacra: Diverge from apical system at angle of 180 degrees, then turn forward, their middle parts making, if produced, an angle of about 45 degrees with each other; then turn laterally and cross the ambitus at a point posterior to the anterior corner of the test. The anterior pore zone has 18 to 20 small, circular, closelyi spaced pore pairs. The posterior zone has about 27 pairs of slit-like pores, the anterior pore being much shorter. Posterolateral ambulacra: Short, inflated centrally diverge at angle of about 130 degrees from each other. Each zone has about 12 pore pairs, those of the posterior zone being more elongate than those of the anterior zone. In each zone the anterior pore is shorter than the posterior. · Apical system.' Four genital plates, their conspicuous thick-lipped per­forations making the four corners of a square. Oculars small, perforated. Peristome: Ovoid, depressed, posterior lip straight, with an elevated median carina behind it. Periproct: Ovoid, inferior margin extended downward; situated at top of vertically excavated area in posterior truncated area. This species is most similar to E. bravoensis Bose, from which it differs in many particulars. E. bravoensis in form resembles E. texanus (Roe­mer) and is the inflated texanus7like species which is widespread in the upper Washita and which has been so frequently mistaken for E. texanus. We have examples of it from the Weno to the Grayson formations, and it has been found in the Buda limestone (Whitney). E. bravoensis is not so tall as E. texanus and is not therefore so inflated as: that species; yet it is more rotund than E. wenoensiS and lacks the angular contour of this species. E. wenoensis is more ovate in form and does not have the long posterior narrowing of the test seen in many individuals of E. bravoensis. It is abruptly narrowed posteriorly and has a truncate posterior end. There is variation in the figured material of E. bravoensis in this regard, and in the absence of a designated type individual it is impossible to say which condition is typical for that species. Bose's plate XLI, figure 5, shows an individual in which the posterior narrowing is slight and the truncation is broad, as in E. texanus or E. mexicanus; in plate XLII, figure 9, the narrowing is prolonged and the truncation narrow, as in E. wenoensis. However, a constant and distinctive feature of E. weno­ensis is that the posterior end of the test is not merely truncate but is deeply excavated vertically, and in this excavation the periproct lies. In E. bravoensis as figured, the apical system is subcentral or at least far­ther forward than in E. wenoensis; the main limits of the antero-laterals therefore diverge at a wider angle (about 80 degrees) in E. bravoensis; University of Texas Bulletin and this position of the apical system is to some extent . correlated wit~ the elongation of the test. The anterior ambital notch m E. wenoew:is is always sharper and deeper than in E. bravoensis; in ~he_ latt~r species it has the same form as in H. riovistae here described, while m this r~s~ect E. wenoensis and H. longisulcus (Adkins and Winton) are closely similar to each other. In E. wenoensis there is a conspicuous high point on the median carina halfway between the apical system and the posterior end of the test; in E. bravoensis and H. riovistae the carina is low and th.e highest point is variable, often lying near the apical system. E. bravoen~is in addition has a distinctly angular inferior inflation to the test which in our species is evenly rounded. ENALLASTER BRAVOENSIS Bose Pl. 8, fig. 4 1910: Enallaster bravoensis Bose, Inst. Geol. Mex., Bol. 25, p. 168, pl. 41, figs. 5-10; pl. 42, figs. 2-12; pl. 43, figs. 1-2, 6-7. 1916: Enallaster bravoensis Whitney, Bull .. Amer. Pal. No. 26, p. 16, pl. 6, figs. 3-5. 1920: Enallaster bravoensis Adkins and Winton, Univ. Texas Bull. 1945, p. 58, pl. 9, fig. 11. ' This species is occ~sional in the Upper Washita formations, Weno to Buda, and in North 'l\exas is still unknown from the lower formations. At Cerro de Muleros it is reported from subdivisions 5, 6, and 8 (Fort Worth to Grayson). This species differs from EnaUaster wenoensis, which also is truncated and tapering posteriorly, by its more elevated and in­flated form, smaller depth of ambulacral grooves, and its taller and dif­ferently shaped longitudinal section in which the anterior slope is shorter, more abrupt and more rounded. ENALLASTER ap. aff. TEXANUS (Roemer) There are in the Upper Washita formations undefined species similar in form to EnaUaster texanus (Roemer). These are abundant in the Weno and Grayson marls, and are in need of study and revision. HEMIASTER CALVINI Clark Pl. 5, figs. 1, 2, 4; Pl. 6, fig. 3; Pl. 8, fig: 6 This species may be recognized by its tall rounded form and its short deep ambulacral grooves. It is somewhat variable in form and size, but Weno and Pawpaw Formations the most common variants are here figured. Form elevated; ·outline angular, broadly truncated and shallowly ex­cavated posteriorly. with a shallow anterior ambital notch, widest just posterior to the antero-lateral ambulacra. The apical system is a little posterior ·to the center of the test, the distances in front of and behind it having the ratio 10 :8. Ambulacra deeply excavated, the unpaired one being longest; the antero-laterals are longer than the postero-laterals (ra­tio 9 :7) ; the antero-laterals diverge at an angle of about 105 degrees, the postero-laterals at about 45 degrees. The unpaired ambulacrum is slightly wider than the others. The posterior median keel and the interambulacral areas are elevated, the former being sharp-topped. Peripetalous fasciole visible but irregular. Pores of unpaired ambulacrum short, sfit like, oblique, separated by a prominent tubercle. Pores of lateral ambulacra elongate transverse slits which are nearly equal in the forward and the rear zones. Peristome elongated transversely, with a prominent thick­ened posterior lip; periproct high, vertically elongate, ovate .. The longi­tudinal section is distinctly elevated, posterior slope straight and inclined, anterior slope rounded, the highest point of the test being on the posterior median keel just back of the apical system. HORIZON: Weno to Buda formations. The Weno marl contains another species which has deeply excavated short ambulacra, much constricted at each end and flared in the middle. These ambulacra are remarkably short and inflated and have a very characteristic appearance. The whole ambulacral syste:rp is placed for-. wards on the test, the posterior median keel and the inter~mbulacral areas are elevated, she outline is almost circular and non-angular, the form is low, and the anterior median notch is shallow. This species has some resemblance to the poorly figured and described species H emiaster bexari Clark. HEMIASTER RIOVISTAE n. sp. Pl. 6, fig. 4; Pl. 8, figs. 2-3, 5 • MEASUREMENTS: (Type) Length on mid-line ---------------------------25.5 Width ----------------------___________ _____ 23.5 Height ------~______----__ _ __ _ __ __ ____ ____ __ 14.0 HORIZON: Top of Weno formation, marl facies. LOCALITY : 720 (type locality) , one mile southeast of Riovista, Texas, and one-half mile east of the Waco road . • University of Texas Bulletin DESCRIPTION-Test: This species has nearly the form of Enallaster bravoensis Bose, but differs in many respects, notably in having the pore pairs of the unpaired ambulacrum all similar. Test low, elliptical in gen­ eral outline, notched at the anterior ambitus, rounded laterally, with three distinct angulations, broadly truncate posteriorly. Anterior sulcus long, apical system situated slightly more than two-thirds the length of the mid-line from the notch of the anterior sulcus. Highest point of test on the low posterior median carina about one-fifth the length of the test from the posterior end. From this point the mid-line curves sharply poster­ iorly to the top of the truncated posterior end. This point is only slightly taller than the edges of the anterior sulcus just in front of the apical system. Slope of test forward from apical system gentle, almost a straight line, similar to that of E. bravoensis Bose. The middle is the most inflated point on the test. Inferiorly the most prominent point is on the mid-line three-fourths the way back from the anterior end ; the shell therefore i:8 tallest at this point and anteriorly is wedge-shaped, as in E. bravoensis Bose. There is an elevated median tuberculated area and the peristome lies in a deep depression of the recurved anterior sulcus and is bounded posteriorly by an overhanging pointed lip. Margins of shell sharply rounded on approaching ambitus, and coarsely tuberculate. Around each tubercle is a circlet of small tubercles, and the intervening spaces recovered by fine granules irregularly scattered. Oval projections of postero-lateral ambulacra consisting of large smooth elongate plates · with scattered tubercles and fine granules. Laterally the test bears sev­ eral fascicle-like bands each consisting of three crowded rows of the smallest sized granules. Anterior unpaired ambulacrum: Long, shallow, sides nearly straight, making a rather shallow notch at the ambitus. Each pore zone has about 32 pairs of transverse slit-like pores, the pores of a pair being separated by a conspicuously elevated, transversely elongate tubercle. The pores are similar and the ten nearest the apical system show a graduation in size; the others are approximately equal, except near the ambitus, where they are more nearly circular. The pore pairs lie each on an elongate ambul­ acral plate which reaches the middle. Each plate has a double row of • small granules. Antero-lateral A.mbulacra: Diverge at an angle of 180 degrees and turn forward mak1~g over the central part of their course an angle of about 47 degrees with each other. They then diverge and cross the am­ bitus. far anteriorly. The anterior pore zone consists of about 22 pores of mmute, closely spaced, circular pores, situated for the most part about Weno and Pawpaw Formations the diameter of a pore apart. These are situated in the antero-median quadrant of a quadrate or trapezoidal ambulacral plate which bears two or three large tubercles. The posterior zone consists of about 32 pairs, each having an anterior oval pore and a posterior wedge-shaped slit nar­ rowest at the forward end. · Postero-lateral ambulacra: Short, rather wide and bulging in the cen­ ter, axes straight diverging at an angle of about 115 degrees from each other. The anterior zone has about 12 pairs of short slits; the posterior about 14 pairs of nearly equal longer slightly oblique slits. All of these pores decrease in size toward each end of the zones. Apical system:· Four genital plates, the right anterior one being the elongated madreporite, the posterior pair slightly farther apart than the anterior pair; four perforated oculars. Peristome: Transversely oval with a slightly emarginate lip. The lip posteriorly is elevated into a blunt high tip or carina. Periproct: In shape an oval, transversely situated but with the rounded inferior margin slightly bulged downward; each diameter (on the type) about 2.8 mm., situated high on posterior truncated surface two-thirds the way up. Aside from generic characters the following differences will assist in separating H. riovistae n. sp. from Enallaster wenoensis n. sp. E. weno­ ensis has the apical system farther forward; the antero-laterals diverge at a slightly greater angle ; the anterior ambital notch is deeper and more sharply incised; the form is broader, less elongate, more nearly circular, distinctly less flat and more constricted posteriorly. The area in which the periproct lies is not merely truncate, but is sharply excavated giving a narrow vertical groove, while in H. riovistae the posterior end of the test is broadly truncate and the excavation is broad and shallow; and the pores of the anterior unpaired ambulacrum are in part alternating long and short pairs, instead of being all similar and separated by a tubercle as in H. riovistae. The more posterior position of the apical system of H. riovistae results in its having a longer anterior &ulcus, it being inter­mediate in this respect between E. wenoensis and H. longisulcus. The an­tero-laterals are in many individuals which are here referred to E. weno­ -ensis much more sunken than in H. riovistae. The only other described species with which H. riovistae might be confused· is E. bravoensis which has long and short pore pairs in the anterior unpaired ambulacrum instead of having all the pore pairs similar. H. longisulcus (Adkins and Winton) has these pore pairs similar, but it is at once distinguished by its lower, more elongate form, and by the unusually long anterior sulcus and the con­sequent posterior position of the apical system. UniDerndy of Te:rn~ Bulletin PELECYPODA NUCULA NOKONIS n. sp. Pl. 10, figs. 12-16, 19-20 I MEASUREMENTS: Length ------------------------------------17.0 mm. Height ---------------------------------13.4 mm. Thickness ---------------------------------8.3 mm. HORIZON: Blue shale and red clay-ironstones of upper half of Weno formation, Red River region. · LOCALITY: 601, pit of brickyards, one and three-fourths .miles south­east of Gainesville, Texas (type locality) ; 604, cut of Frisco track, three­fourths mile north of Union Station, Denison, Texas. DESCRIPTION: Shell inequilateral, sub-equivalved, sub-triangular in contour, with fine radial ribs. Right valve, exterior: Beak sharply rounded, angle 100 degrees; a straight rounded ridge runs from the umbo to the anterior angle, making with the anterior margin a long low triangle\ whose othC:1r two sides are almost straight portions of the anterior margin. These portions are in length as two to one, the dorsalmost portion being the lunger, and make with each other an angle of 15 degrees. The ventralward portion, if ex­tended, would make with the extended ventral side an anterior ~n~le of 60 degrees ; the actual angle is sharply rounded. The ventral margin is gently convex downward, and extends backward to the sharply rounded posterior angle ( 90 degrees) . The postero-dorsal margin is straight. The ornamentation consists of about 47 very flat low radial ribs ·which ure unbranched and continuous from beak to ventral margin. Between these lie fine straight depressions one-sixth to one-eighth the width of a rib. The ribs are crossed by fine scalloped growth lines with the convex­ ities pointed ventrally, giving to the growth lines a fine crenulate appear­ ance. On the anterior area (lunule) the ribs disappear and the growth lines thicken slightly. This area contains a radial anterior ridge anrth, Texas. Other individuals, x 2.0, same locality. Figure 14. Schloenbachia wenoensis n. sp . ..... . .......... . ...........Pase 89 Rare, Pawpaw formation, base, clay fades. Fig. 14, type indivitlual, x 2.0. Locality: 723, near Fort Worth, Texas. University of Texas Bulletin No. 1856 Plate 1 2 15 ... · it 20 ~ ..· PLATE 2 Scaphite~, Hamulina, Metopaster, Comptonia University of Texas Bulletin PLATE 2. Scaphites, Baculites, P'tychoceras, Metopaater, Comptonia Plate 2 f'igures 1-12. Scaphites hilli Adkins·and Winton ........................Page 79 Occasional, basal 10 feet of the Pawpaw formation, clay facies, sparse outside of Tarrant County region. Fig. 1, type individual, x 4.0, ventral view, showing suture and mid-ventral groove. Locality: 714, near Fort Worth, Texas. Fig. 2, individual showing venter with sutures outlined in the hematite and Jimo­nite areas, x 4.0. Locality: 714. Fig. 3, individual showing suture, dorso­lateral tubercle, and aperture, x 4.0. Locality: 714. Fig. 4, same individual, reverse side, x 5.0. Figs. 5, 6, individuals x 4.0. Locality: 714. Fig. 7, indi­vidual showing uncoiled portion and dorso-lateral tubercle, x 2.0. Locality: 723, near Fort Worth, Texas. Fig. 8, individual showing uncoiled portion, · tubercle and juvenile suture, x 4.0. Locality: 723. Figs. 9-12; showing rib variations, x 4.0. Locality: 723 . . Figures 13, 15-18. Scaphites sp. aff. hilli Adkins and Winton ............ ....... . Occasional, Pawpaw clay, base. Fig. 14, x 3.0; figs. 13, 16-18, x 2.0, showing rib variations. Locality: 713, near Fort Worth, Texas. Figure 14. Metopaster hortensae Adkins and Winton .....................Page 97 Rare, Pawpaw formation, base, clay facies. Type individual, aboral side, x 2.0. Locality: 714, near Fort Worth, Texas. Figure 19. Comptonia wintoni n. sp ..................................Page 97 Rare, Pawpaw formation, base, clay facies. Type individual, aboral side, x 3.0. Locality: 714, near Fort Worth, Texas. Figures 20-22. Baculites comanchensis n. sp ..........................Page 74 Occasional, Pawp;:i.w formation, base, clay facies. Type individual. Fig. 21, x 4.0. Locality: 719, near Fort Worth, Texas. Fig. 20, x 2.0, same locality. Fig. 21, x 2.0. Locality: 714, near Fort Worth, Texas. Figures 23-26. Hamulina worthensis n. sp............................Page 71 Rare, basal Pawpaw clay. Type individual, Fig. 26, x 5.0, showing suture. Locality: 714. Fig. 23, individual showing form of. curve and short limb, x 4.0. Locality: 714. Fig. 25, same individual, ventral view, x 2.0. Fig. 24, individual showing form of long limb and of curve, x 4.0. Locality: 714. Individuals of Figs. 23, 24 in museum of Texas Christian University, ·Fort Wortbi Texas. University of Texas Bulletin No. 1856 Plate 2 5 8 21 " 22 ,_ PLATE 3 . Turrilites, Acanthoceras, Schloenbachia University of Texas Bulletin PLATE 3. Turrilites, Acanthoceras, Schloenbachia Plate 3 r.:igures 1, 6. Turrilites worthen1i1 Adkins and Winton .................Page 78 Abundant, Pawpaw formation, base, clay facies. Fig. 1, x 4.0; locality: 714, near Fort Worth, Texas. Fig. 6, showing portion of suture, x 4.0; locality: 714, near Fort Worth, T-exas. Fi.gures 2, 4. Turrilites sp.......................... ·................Page 78 Abundant, Pawpaw formation, base, clay facies. x 4.0; locality: 714, near Fort Worth, Texas. Figures 3. 7. Turrilites bosquensis n. sp..............................Page 76 Rare, top of Exogyra arietina horizon, middle Del Rio clay (equivalent of base of the Grayson formation). Locality: cliff on west bank of the South Bosque River, 100 yards south of the bridge of the Speegleville road, and 5.5 miles west of the courthouse at Waco, Texas. Fig. 3, type individual, x 4.0, show­ing tubercles and angularity of profile. Fig. 7, same individual, x 2.0, show­ing aperture. l<'igure 5. Acanthoceras worthense n. sp...............................Page 93 Abundant, basal and middle Pawpaw clay. Individual showing venter, x 4.0~ Locality: 714, near Fort Worth, Texas. Figures 8-11. Schloenbachia wintoni n. sp ........·............... ; .....Pas• 90 Occasional, Pawpaw formation; abundant, W eno formation. Figs. 8, 11, type individual, x 1.0; locality 601, near Gainesville, Texas, nacreous individual from ironstone in upper third of Weno formation. Figs. 9-10, nacreous indi­vidual, x 1.0, same locality. Fig. 9 shows the slightly bifid marginal tubercles. Type in museum of Texas Christian University, Fort Worth, Texas. University of Texas Bulletin No. 1856 Plate 3 PLATE 4 Schloenbachia, Engonoceras, Flickia, Corbula University of Texas Bulletin PLATE 4. Schloenbachia Engonocreaa, Flickia, Corbula Plate 4 Figure 1. Scbloenbachia sp ............................................... . Rare, Pawpaw clay, x 4.0. Locality: 714, near Fort Worth, Texas. (See Pl. 1, fig. 5.) Figure 2. Engonoceraa sp ..........................................Page 85 Rare, Pawpaw clay, x 2.5. Locality: 714, near Fort Worth, Texas. li'igure 4. Acanthoceraa worthenae n. sp. . . . . . . . . . . . . . . . ..... . ...... . . Page 93 Abundant, Pawpaw clay, x 4.0. Locality: 714, near Fort Worth, Texas. l"igures 3, 5-6, 12. Engonoceraa aerpentinum (Cragin) .................Page 84 Occasional, Weno shale, Grayson and Cooke counties, Texas and southern Okla­homa; rare, Pawpaw clay and shale. Figs. 3, 5, x 2.5; locality: 714, near Fort. Worth, Texas. Figs. 6, 12, x 1.0; locality: 604, near Denison, Texas. Figu~es 8-10. Engonoceraa sp.... . .......................•...........Page 85 Very abundant, Pawpaw clay, especially near the base; rare, Grayson, Denton, and Duck Creek formations, clay and marl facies, x 3.0, locality: 714, near Fort Worth, Texas. Figure 11. Flickia (?) boaquenaia n. sp. . . . . . . . . . . . . . . . . ........... . ..Page 87 Rare, top of Exogyra arietina horizon, middle Del Rio clay (equivalent of base of Grayson formation). Type individual, x 4.0. Locality: cliff on west bank of South Bosque River, 100 yards south of the bridge of the Speegleville road, and 5.5 miles west of the courthouse at Waco, Texas. (See pl. 1, fig. 4.) University of Texas Bulletin No. 1856 Plate 4 PLATES Hemiaster, Epiaster, Enallaster ,, University of Texas Bulletin PLATE 5. Hemiaster, Epiaster, Enallaster Plate 5 Figures 1-2, 4. Hemiuter calvini Clark ............. ................Page 114 Occasional, Weno and Pawpaw formations; rare, Denton and Mainstreet forma­tions; abundant, middle Grayson formation. Fig. 1, large sized individual with strongly developed ambulacral grooves, x 2.0; locality: Argyle, Texas, Gray­son marl, Baylor University Museum. Fig. 2, individual in some ·respects re­sembling H emiaster bexwri Clark, x 3.0; locality: 720, basal Pawpaw marl, near Riovista, Texas. Fig. 4, x 2.0; locality: west branch of Little Mineral Creek, one mile northeast of Fink, Texas. Figure 3. Enallaster wenoensis n. sp ................................Page 112 Abundant, W eno formation, marl facies; rare, Pawpaw formation, marl and clay facies. Type individual, x 4.0; locality: 720, basal PawJ.•aw marl, ·near Rio­vista, Texas. . Figure 5. Epiaster aguilerae Bose ................................. ~Page 109 Rare, basal Fort Worth limestone. Locality: 406, one-half mile east of Texas Christian University, Fort Worth, Texas. Aboral side, x 1.0. Unive~sity of Texas Bulletin No. 1856 Plate 5 PLATE 6 Remondia( ?) , Venericardia, Amberleya, Hemiaster, [piaster - 160 University of Texas Bulletin PLATE 6. Remondia, Venericardia, Amberleya, Hemiaster, Epiaster Plate 6 Figure 1. Remondia (?) acuminata (Cragin) ........................Page 136 Occasional, basal Weno marl; rare, Pawpaw clay. Locality: 618, near Fort Worth, Texas, individual, x 1, showing hinge structure. Figure 2. Venericardia wenoensis n. sp.........•................... :Page 125 Occasional, Weno formation, shale facies, Red River region, and marl facies, Fort Worth region. Fig. 2, individual, x 2.0, showing ribbing. Locality: 618, near Fort Worth, Texas. Figure 3. Hemiaster calvini Clark ..................................Page 114 Occasional, Weno and Pawpaw formations. Fig. 3, x 3.0. Locality: 903, Gray­son marl, one-half mile southeast of Denison, Texas. Rare, basal Pawpaw formation, clay-marl transition area; rare, Weno marl. Type individual, x 4.0. Locality: 720, near Riovista, Texas. . -. -··,:~·.--,.· ·~t-• . t ' I Figure 4. Hemiaster riovistae n. sp ..................................Page 115 Rare, Weno formation, shale facies. Locality: 606, basal stratum of Weno form­ation, near Denison, Texas. Type individual, x 2.0, showing carinae and ribbing. Figure 5. Amberleya graysonensis n. sp .............................Page 137 Abundant, basal Weno formation, marl facies; rare. Pawpaw clay and marl. Type individual, x 1.0. Locality: 618, near Fort Worth, Texas. F'igure 6. Epiaster wenoensis n. sp .................................Page 105 Abundant, basal W-eno formation, marl facies; rare, Pawpaw clay and marl. Type individual, x 1.0. Locality: 618, near Fort Worth, Texas. University of Tex.as Bulletin No. 1856 Plate 6 PLATE 7 Pentaceros, Comptonia, Metopaster, Pentagonaster Unii1ersity of Texas Bulletin PLATE 7 Pentaceroa, Comptonia, Metopaater, Pentagonaater Plate 7 Figures 1-3. Pentacetoa americanua n. sp..............................Pase 99 Pawpaw formation, clay facies, basal 5 feet, rare. Fig. 1. Type individual, aboral side, x 2. Locality: 714, one-fourth mile south of the International and Great Northern Railway bridge across Sycamore Creek, four and one-half miles southeast of Fort Worth, Texas. The large plate above and to the left of the center of the disk is the madreporite. Type in museum of Texas Christian University, Fort Worth, Texas. Fig. 2. Type individual, oral side,. x 2. Fig. 3. Type individuai, aboral silie,. x 1.5; . Figures 4-5. Comptonia wintoni n. sp ................................Pase 97 Pawpaw formation, clay facies, basal portion, rare. Fig. 4. ':Pype individual, aboral side, x 2. Locality: 714; near Fort Worth, Texas. Fig. 5. Type individual, oral side, x 2. Figure 6. Metopaater hortenaae Ad.kins ·and Winton. . . . ................Pase 97 Pawpaw formation, clay facies, base, rare. Type individual, oral side, x 2. Locality: 714, near V'crt Worth, Texas. Figure 7. Pentagonaster texenaia Adkbs and Winton ....................Pase 95 Weno formation; limestone facies, upper 10 feet. rar~ Locality: 602, east bank of Sycamore Creek, about four mile8 !outheast of Fort Worth, Texas. Aboral side, x 1.5. Figured individual in museum of Texas Christian University, Fort Worth, Texas. University of Texas Bulletin No. 1856 Plate 7 PLATE 8 Hemiaster, Epiaster, Enallaster • University of Texas Bulletin PLATE 8. Hemiaster, Epiaster, Enallaster. Plate .8 Figure 1. Hemiaster longisulcus (Adkins and Winton) ....................... . Occasional, top of Fort Worth limestone. 'l;pe individual, x 2.0. Locality: On Cedar Creek, two miles southeast of Blum, Texas. Note the similar pores of the anterior unpaired ambulacrum1 and the posteriorly placed apical system. Figures 2-3, 5. Hemias.ter riovistae n. sp.............................Page 115 x 2.0. Locality: 720, near Riovista, Texas. F'igure _4. Enallaster hravoensis Bose................................Page 114 Occasional, Weno formation, marl and clay facies; rare, Pawpaw, Mainstreet and Buda formations; abundant, Grayson formation, marl and clay facies. Fig. 4, individual x 2.0. Locality 618, near Fort Worth, Texas. Figure 6. Hemiaster calvini Clark...................................Page 114 Locality unknown, Cummins Collection. Note position of apical system, and the deep ambulacral grooves. Figure 7. Epiaster aguilerae Bose ..................................Page 109 Rare, basal Fort Worth limestone. Locality: 406, one-half mile east of Texas Christian University, Fort Worth, Texas. (Same individual as Pl. 5, fig. 5.) Apical system, x 4.0. University of Texas Bulletin No. 1856 Plate 8 PLATE 9 Cyprimeria, Corbula University of Texas Bulletin PLATE 9. Cyprimeria, Corbula Plate 9 Figures 1-6. Cyprimeriia wa1hitaen1i1 n. sp.. ........................Page 134 Occasional, W eno shale, Cooke and Gr:ayson counties, Texas. Fig. 1, type indi­vidual, x 1.0; ~ocality: 604, near Denison, Texas. Figs. 2-4, x 1.0, same locality. Figs. 3-5, individuals showing hinge structure, x 1.0, same locality. Fig. 6,• individual showing posterior adductor muscle scar and part of pallial line, x 1.0, same locality. : }i'igures 7-24. Corbula basiniformis ::i. sp .. . ............ •. ........... .Page 130 Abundant, W eno shale and ironstone. Cooke and Grayson counties, · Texas and southern Oklahoma. Fig. 21, type individual, x 1.5; locality: 604, near Den­ison, Texas. Other individuals, x 1.5, same locality. University of Tex.as Bulletin No. 1856 Plate 9 , PLATE 10 Corbula, Arca, Protocardia, Neritina, Nerita, Natica, Lunatia, Trochus, Anchura, Cinulia, Glohiconcha, Turritella. University of Texas Bulletin PLATE 10. Corbula, Nucula, Arca, Protocardia; Neritin•a, Nerita, Natica, Lul1llltia,· Plate 10 Trochus, Anchura, Cinuliia, Globiconcha, Turritella Figures 1-4. Corbula wenoen.sis n. sp ............ ·....................P'age 127 Weno shale, rare. Fig. 4, type. All individuals x 1.5. Locality: 601, pit of brickyards, one and three-fourths miles southeast of Gainesville, Texas. Figure 5. Corbula littoralis n. sp............................. ."...... Page 133 Weno shale, rare. Fig. 5, type individual, x 1.5. Locality: 601, pit of brick­yards, one and three-fourths miles southeast of Gainesville, Texas. Figure 6. Arc.a washitaensis n. sp ...................................P•age 121 Abundant, Pawpaw clay; rare, Grayson, Denton and Duck Creek formations, clay facies and more rare in the marl facies. Fig. 6, type individual, x 1.5. Locality: 714, one-fourth mile south of the International and Great Northern ·Railway bridge across Sycamore Creek, near Fort Worth, Texas, at the base of the Pawpaw clay. Figures 7-9. Corbul!a basiniformis n. sp , .............................Page 130 Abundant, W eno shale. Locality: 604, cut of St. Louis and San Francisco Rail­way, one mile north of Union Station, Denison, Texas. (See Pl. 9, figs. 7-24.) x. 1.5. !<'igures 10111. Nucula wenoensis n. sp ............................. . . Page 120 Rare, Weno shale. Fig. 10, type individual, x 1.5. Fig. 11, x 1.5. Locality: 601, pit of brickyards, one and three-fourths miles southeast of Gainesville, Texas. l"igur.es 12-16, 19-20. Nucula nokonis' n. sp ..........................Page 118 Occasional, W eno shale, x 1.5. Locality: 604, near Denison,. Texas. Type, Fig. 19, x 1.5, same locality. F'igures 21-26, 32. Protocardia sp. aff. multistriata (Shumard) ..........P.age 126 Abundant, Weno ironstone and shale, x 1. Locality: 601, near Gainesville, Texas. Figure 27. Neritina sp .... ......................... ...............Page 139 Rare, middle Weuo shale (buff marl). Locality: 601, near Gainesville, Texas. x 1.5. Figure 28. Nerita sp..... .. ................ .. ...... .. .............Page 139 Rare, middie W eno shale. Locality: 601, near Gainesville, Texas. x 1.5. F'igure 29. Natica sp .............................................Page 140 Rare, ironstone and upper Weno shale. Locality: 601, near Gainesville, 'fe:xas. -Weno and Pawpaw P01·mations Figures 30-31. Trochua laticonicua n. sp. . . . . . . . . . . . . . . . . . . . . ........P·a ge 138 Rate, middle Weno shale (buff marl). Locality: 601, near Gainesville, Texa1:1. Fig. 30, type individual, x 1.5. Fig. 31, x 1.5. Figures 33-37. Cinulia waahitaenaia n. sp ............................Plllge 143 Occasional, middle and upper Weno shale. Locality: 601, near Gainesville, Tcxns. Fig. 33, type individual, x 1.5. Figs. 34-37, x 1.5. Figure 38. Lunatia sp . ....... ... . .... . ...... . ... . ... . .... . . ..... . Page 140 Rare, Weno ironstone and upper W eno shale. Locality: 601, near Gainesville, Texas. x 1.5. Figures 39-40. Anc,hura mudgeana Whit-e .................. . ... ......Page 139 Abundant, middle and upper Weno shale, Cooke and Grayson counties, Texas. Locality: 604, near Denison, Texas. x 1.5. Figure 41. Globiconcha sp . ..... ... .......... . . . .... . ..............Page 140 Rare, Weno ironstone. Locality: 601, near Gainesville, Texas. x 1.5 . Figure 42. Turritella worthenaia n. sp .............. . . .. ... . . . . . . . . . . Page 142 Abundal}t, lower Weno marl. ·Tarrant County, Texas. Type. Locality, 618, near Fort Worth, Texas. Fig. 42, type invidual, x 1.5. Figure 43. Turritella grayaonenaia -n. sp ......... ....................Page 140 Abundant, Weno shale, Grayson County, Texas; occasional, Cooke County, Texas: Locality: 604, near Denison, Texas. Type, Fig. 43, x 1.5. • •t of Texas Bulletin No. 1856 Un1vers1 Y Plate 10 PLATE 11 .Pecten, Epiaster, Nodosaria, Ancycloceras University of Texas Bulletin PLATE 11. Pecten, Epiaater, Nodoaari·a, Ancycloceraa. Plate 11 Figure 1. Ancycloceraa bendirei n. sp. . ..............................Page 70 Rare, Weno formation, base, marl facies. Fig. 4, type individu;al, x 1.2. Locality: 618, near fort Worth, Texas. Figure 2. Nodoaaria texana Conrad .................................Page 145 Abundant as isolated individuals and rarely in slabs, upper third of Weno and base of Pawpaw formations in north central Texas; abundant in flag layers, upper and to a less extent the middle Del Rio clay in West Texas. Fig. 3, x 5.0. Locality: Terlingua, Texas. (Compare Univ. Texas Bull 1945, pl. 21.) I<'igure 3. Epiaater subobeaua n. sp ..................................Page 110 Occasional, Weno formation, marl facies, and Pawpaw formation, marl facies. Abundant near base of Weno, in the "first terrace" of the Fort Worth region; Fig. 2. ·Locality: 618, near Fort Worth, Texas, type individual, x 1.0. Figure 4. Pecten inconapicuua Cragin ............................ ...Page 123 Abundant, Weno shales and ironstone; rare, Denton clay; rare, Pawpaw forma­tion, sand and ironstone facies. Cooke and Grayson counties, Texas, and southern Oklahoma. Fig. 1, clay-ironstone shell conglomerate 0 from the middle Weno shales, x 4.0. Locality: 604, near Denison, Texas. University of Texas Bulletin No. 18!:'.6 Plate 11 Ori A New Ammonite Fauna of the Lower Turonian of Mexico ' BY Emil Bose CONTENTS INTRODUCTION. . 179 STRATIGRAPHY.. 183 ON THE RELATIONS BETWEEN THE FAUNA OF CERRO DEL MACHO AND ISOCHRONOUS FAUNAS OF OTHER REGIONS OF THE EARTH 192 PALEONTOLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20(• CEPHALOPODA............. .... ....... ·........... ... . . . . . . . . . . . 200 Metoecoceras Hyatt........................................ , . 200 Metoecoceras aff. whitei Hyatt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 Metoecoceias sp. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20i5 Mammites Laube et Bruder, emend. Petrascheck. . . . . . . . . . . . . . . . . . 206 Mammites mobovanensis sp. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . 206 Pseudaspidoceras Hyatt, emend. Pervinquiere. . . . . . . . . . . . . . . . . . . . . 208 Pseudaspidoceras aff. footeanum Petrascheck. . . . . . . . . . . . . . . . . 208 Pseudaspidoceras aff. pedroanum White. . . . . . . . . . . . . . . . . . . . . . 209 · Fagesia Pervinquiere. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 Fagesia haarmanni sp .nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 Fagesia pervinquieri sp. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 Vascoceras· Choffat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Vascoceras sp. nov. ex. aff. V. adonense Choffat ........... ·.;. . 214 Vascoceras aff. giamai Choffat . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21f; Vascoceras angermianni sp. nov..........· . . . . . . . . . . . . . . . . . . 217 Vascoceras sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 V'ascoceras mohovanense sp. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . 219 Neoptychites Kossmat. . . ................. : ....... ·•. . . . . . . . . . . . 221 Neoptychites aff. cephalotus Courtiller. . . . . . . . . . . . . . . . . . . . . . 221 Neoptychites aff. xetriformis Pervinquiere. . .. . . . . . . . . . . . . . . . . . 223 Hoplitoides v. Koenen, emend. Solger et Pervi!lquiere. . . . . . . . . . . . . . 225 Hoplitoides aff. mirabilis Pervinquiere. . . . . . . . . . . . . . . . . . . . . . . 225 LAMELLIBRANCHIATA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227 Avicula Brug_uiere. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 227 Avicula aguilerae sp. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227 lnoceramus Sowerby. . ..................... · ....... · . . . . . . . . . 229 lnoceramus labiatus Schlotheim . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 University of Te:ms Bulletin Exogyra Say. . 230 Exogyra ha·armanni sp. nov.................. : ............ . 230 Exogyra cfr. olisiponensis Sharpe .......... . .............. . 280 GASTROPODA.. 232 Tylostoma Sharpe. . ... .......... ............................. . 232 Tylostoma aff. ov•atum Sharpe ...... . ....... .... . . .... . .. . . 232 ECHINODERMATA. . . . · . ........ . .... .. .... .... . . ......... ...... . 232 Hemiaster Desor.. 232 Hemiaster sp. . ... .. ... .... .. ...... ......... ....... .. . . . . 23::! LIST OF ILLUSTRATIONS FIGURES Figure 1. Metoecoceras aff. whitei Hyatt, suture. . . . . . . . . . . . . . . . . . . . . . . . . 204 Figure 2. Suture, Vascoceras angermanni 11. sp. (above) and Vascoceras aff. adonense Choffat (bclow) ...................... . ..... 215 Figure 3. Suture, Vascoceras aff. gam.ai Choffat..... .. . . ................ 216 Figure 4. Sutures, Vascoceras mohovanense n. sp. (above), and Mammites mohovaensis n. sp. (below) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 Figure 5. Suture, Neoptychites aff. cephalotus Courtiller. . . . . . . . . . . . . . . . . . 222 Figure 6. Suture, Neoptychites aff. cephalotus Courtiller. . . . . . . . . . . . . . . . . . 22~ Figure 7. Sutures, Neoptychites aff. xetriformis Pervinquiere (lower left hand corner) and Hoplitoides sp. (other three). . . . . . . . . . . . . . . . 226 PLATES Plates 12-20. Lower Turonian Fossils from Cerro del Macho ..... . .. . .. . 235-2152 • ON A NEW AMMONITE FAUNA OF THE LOWER TURONIAN OF MEXICO BY EMIL BoSE INTRODUCTION A number of years ago the existence of Turonian beds was proven in Mexico and later on it was shown that these beds have a great distribu­tion in the country. At first very few localities with faunas of this age were known, but later the finds of fossils of Turonian age have augmented in such a manner that we now know that the Turonian has a vast dis­tribution in Mexico, numerous localities having been discovered between Lat. 20°30' N. and Lat. 32° N. All of these beds are petrographically very uniform and consist of argillaceous shales and laminated limestones with intercalations of thin beds of limestone, all of black to light gray color. The fauna of these beds is also rather uniform and consists mostly of numerous specimens of Inoceramus labiatus Schlotheim, in some places accompanied by Inoceramus hercynicus Petraschek; in some localities fishes are relatively numerous; in others bivalves other than Inoceramus are found. Cephalopods have been found very rarely, all of them crushed and nearly indeterminable. The determination of the age had to be founded exclusively on the Inoceramus and on the position of the beds in relation to the Senonian and the Cenomanian. About nine years ago I received the first collections of Turonian am­monites, which allowed a much better determination of the age of the beds mentioned here because these cephalopods were found together with well preserved specimens of the same Inoceramus which already had been determined by us as I. "labiatus. ·In February, 1911, Dr. Ernst Angermann sent me a small collection • of fossils collected by him on the Cerro del Macho, Hacienda del Moh6vano, Municipality of San Pedro, District of Parras in the State of Coahuila. The greater part of these fossils consisted of internal molds of bivalves and gastropods, but there were also present three cephalopods relatively badly preserved and several indeterminable fragments o{ ammonites. I recognized at once that these fossils belonged to a facies and a horizon altogether unknown in Mexico, one of the ammonites being a Vascoceras of the group of V. Kossmati and another a N eoptychites of the group of N. xetriformis Pervinquiere, the bivalves belonged mostly to Trigonia, University of Texas Bulletin 180 A vicula of the group of A. gravida Coquand, the gastropods to Tylostoma and similar genera. A short time afterwards I showed these fossils to Dr. E. Haarmann, geologist of the Cia. Perforadora Mexicana, who then told me that he had a much larger collection of fossils from the same locality which he had made before Dr. Angermann had visited the place; and he offered me his material for a detailed paleontological study. The collection of Dr. Haar­mann proved to be much larger than that of Dr. Angermann and con­tained a large number of ammonites some of which were rather well preserved. Haarmann in making his collection had· separated the f os­sils of the different beds. The lowest of these beds was represented by a single piece of rock with impressions of bivalves, but as this rock had a very distinct character from that of the other beds and as in a locality of apparently the same age a badly preserved sea urchin had been found which appeared to belong to Hemiaster, I asked Dr. Haarmann to collect better material in the lowest horizon, because this horizon seemed to be­long to the Cenomanian. Haarmann visited the locality again in August, 1911, collected ammonites in each of the three beds distinguished by him, and turned this material over to me in April, 1912. The material thus collected proved to be of great stratigraphical and paleontological interest, as will be shown by the following description. But before I enter into a detailed study I wish to express· my gratitude to Dr. E. Haarmann to whose amiability I owe the opportunity of studying this interesting fauna. I also wish to express my obligations to Professor Dr. W. Branca in Berlin who kindly sent me a great number of photo­u;raphs of Turonian ammonites from Egypt, studied by Dr. Eck but at that time still undescribed. LIST OF LITERATURE CITED IN THIS PAPER 1. Boule, Lemoine et Thevenin, Diego Suarez.-M. Boule, P. Lemoine et A. Thevenin, Paleontologie de Madagascar. Cephalopodes cretaces des environs de Diego­ • Suarez.-Ann. de Palontologie t. I et II, Paris, 1906-07. 2. Choffat, Especes nouv. ou peu conn.-P. Choffat, Recueil d'etudes paleontologiques sur la faune cretacique du Portugal. Vol. L, Especes nouveJles ou peu connues. Ire. serie. Section des Travaux geologiques du Portugal. Lisbon, 1886. 3. Choffat, Syst. cret. Portugal II.-P. Choffat, Recueil de Monographies strati­graphiques sur le systeme cretacique superieur au nord du Tage. Service geol. du Portugal. Lisbonne, 1900. 4. Chudeau, Ammonites du Damergou.-R. Chudeau, Ammonites du Damergou (Sahara meridional) .-Bull. Soc. geol. France, 4me ser., t. 9, fasc. 1-2, 1909. 5. Coquand, Geol. et Pal. de Constantine.-H. Coquand. Geologie et Paleontologie de la region sud de la Province de Constantine. Mem. Soc. d'Emulation de la Provence, II. Marseille, 1862. .. A New Ammonite Fauna of the Lower Turonian of Mexico 181 6. Cotteau, Peron et Gauthier, Ech. foss. de l'Algerie.-Cotteau, Peron et Gauthier, Echinides fossiles de l'Algerie. Description des especes deja recueillies das ce pays et considerations sur leur position stratigraphique. IV, Etage Ceno­manien. Paris, 1878. 7. Eck, Turon in Aegypten.-0. Eck, VorUiufige Mitteilungen iiber die Bearbeitung der Cephalopoden der Schweinfurthschen Sammlung und Uber die Entwick­lung des Turons in Aegypten. Monatsber. d. Deutsch. Geol. Ges. 1910. Ber­lin, 1911. 8. Fourtau, Faune cret. d'Egypte.-R. Fourtau, Contribution a l'etude de la faune cretacique d'Egypte. Bull. Institut Egyptien, ser. 4, vol. 4, 1903. 9. Fritsch, Ceph. bohm. Kreideform.-A. Fritsch, Cephalopoden der bohmischen Kreideformation (unter Mitwirkung des Dr. Urb, SchlOnbach). Prag, 1872. 10. Geinitz, Elbthalgebirge.-H. Br. Geinitz, Das Elbthalgebirge in Sachsen. Pala­eontographia Bd. 20, I u. II. 1872-75. 12. Gueranger, Album Paleontol.-Ed. Gueranger, Album Paleontologique de la Sarthe representant au moyen de la photographie les fossiles recueillis dans cette circinscription. Le Mans, 1867. 13. Guillemain und Harbort, Profil d. Kreidesch. a. Mungo.-C. Guillemain und E. Harbort, Profil der Kreideschichten am Mungo. Abh. d. k. Preuss. Geol. Landesanstalt. Neu Folge, Heft 62, 1909. 14. Haug, Traite de Geologie. Paris, 1908-11. 15. Hyatt, Pseudocer.-A. Hyatt, Pseudoceratites of the Cretaceous. Edited by T. W. Stanton. U. S. Geol. Surv. Monogr. vol. 44, Washington, 1903. 16. Jack and Etheridge, Queensland.-R. L. Jack and R. Etheridge, Jr. . The Geology and Paleontology of Queensland and New Guinea. Brisbane and London. 1892. 17. v. Koenen, Nachter. Foss. Mungo ht Kamerun.-A~ von Koenen, Nachtrag zu Ueber Fossilien der Unteren Kreide am Ufer des Mungo in Kamerun. Abh. K. Ges. d. Wiss. zu Gottingen, Math. Phys. Kl. Neue Folge, Bd. 1, No. 1, 1898. 18. Kossmat, Siidind. Kreideform.-Fr. Kossmat, Untersuchungen iiber die siidin­dische Kreideformation. Beitrage zur Palaeontologie und Geoiogie Oester­reich-U ngarns und des Orients, I Bd. 9, 1895; II u. III Bd. 11, 1897. 19. Lartet, Geol. de la Palestine.-L. Lartet, Essai sur la geologie de la Palestine et des contrees avoisinantes telles que l'Egypte et l'Arabie. II me partie Paleontologie. Ann. d. Sciences Geologiques publ. s. 1. dir. de M. Hebert et A. Milne-Edwards. T. III. Paris, 1872. 20. Laube und Bruder, Amm. d. bohm. Kreide.-G. C. Laube und G. Bruder, Ammo­nites der bOhmischen Kreide. Palaeontographica Bd. 33, 1887. 21. Lisson, Amm. del Peru.-C. I. Lisson, Contribuci6n al conocimiento sobre algunos Ammonites del Peru. 4o Congreso cientifico Latino-Americano, lo Panamer­icano, celebrado en Santiago de Chile. Lime, 1908. 22. Lisson, Terr. recon. en el Peru.-C. I. Lisson, Terrenos reconocidos hasta hoy en el Peru y sinopsis de su fauna y flora f6siles. Bol. de Minas, Ind. y Constr publ. por la Escuela de Ingenieros, ser. II, t. IV. Lima, 1912. 23. Peron, Amm. du Cret. sup. de l'Algerie.-A Peron, Les ammonites du Cretace superieur de l'Algerie. Mem. Soc. geol. France, Paleontologie, t. 6 et 7 mem. no. 17. 1896-97. 24. Pervinquiere, :Et. geol. Tunisie.-L. Pervinquiere, Etude geologique de la Tmiisie University of Texas Bulletin Centrale. Theses presentees a la Faculte des Sciences de Paris p. obt. le grade de Docteur-es-Sciences Naturelles. Paris, 1903. 25. Pervinquiere, Paleontologie Tunisienne.-L. Pervinquiere, Etudes de Paleontologie Tunisienne. I Cephalopodes des Terrains Secondaires. Dir. Gen. des Travaux Publics, Carte geol. de la Tunisie. Paris, 1907. 26. Petrascheck, Amm. d. sachs. Kreideform.-W. Petrascheck, Die Ammoniten der sachsischen Kreideformation. Beitr. z. Pal. u. Geol. Oesterreich-Ungarns u. d Orients. Bd. 14, 1902. 27. Petrascheck, Inoc. a. d. Kr. Bohmens.-W. Petrascheck, Ueber Inoceramen aus der Kreide Bohmens und Sachsens. J ahrb. d. K. K. Geol. Reichsanstalt. Wien Bd. 53, 1903 (1904). 28. Roemer, Kreidebild. v. Texas.-F. Roemer, Die Kreidebildungen von Texas und ihre organischen Einschliisse. Bonn, 1852. 29. Schlagintweit, Vracon u. Cenoman in Peru.-0. Schlagintweit, Die Fauna des Vracon und Cenoman in Peru. N. J ahrb. f. Min., Geol. u. Pal., Beilagebd. 33, 1912. 30. Sharpe, Secondary distr. of Portugal.-D. Sharpe, On the Secondary District of Portugal which lies on the North of the Tagus. Quart. Jour. Geol. Soc London, Vol. VI, 1850. 31. Sharpe, On Tylostoma.-D. Sharpe, On Tylostoma, a proposed genus of Gaste­ropodous Mollusks. Quart. Jour. Geol. Soc. London, Vol. 4, 1849. 32. Solger, · Mungokreide.-Fr. Solger, Die Fossilien der Mungokreide von Kamerun und ihre geologische Bedeutung, mit besonderer Beriicksichtigung de~ Am· moniten. Beitrage zur Geologie von Kamerun herausgeg. v. E. Esch. Stutt­gart, 1904. 33. Stanton, Colorado Form.-T. W. Stanton, The Colorado Formation and its in­vertebrate Fauna. U. S. Geol. Surv. Bull. No. 16, 1893. 34. Stoliczka, Ceph. Cret. Rocks India.-F. Stoliczka, The fossil cephalopoda of the Cretaceous Rocks of Southern India (Ammonitidae). Mem. of the Geolog­ical Surv. of India. Palaeontologia Indica, 1865. 35. Thomas et Peron, Hauts-Plateaux de la Tunisie.-Ph. Thomas et A. Peron Description des mollusques fossiles des Terrains Cretaces de la region sud des Hautes-Plateaux de la Tunisie recueillis en 1885 et 1886. Exploration Scientifique de la Tunisie. Paris, 1889-90. 36. White, Inv. foss. Nevada, Utah, etc.-Ch. A. White, Report upon the inverte­brate fossils cqllected in portions of Nevada, Utah, Colorado, New Mexico, and Arizona, by parties of the expeditions of 1871, 1872, 1873 and 1874. Report upon Geogr. and Geol. Exp]. and Surv. west of the lOOth Meridian by Geo. A. Wheeler. Eng. Dept. U. S. Army, Part IV Palaeontology. Wash­ington, 1875. 37. White, Brazil.-Ch. A. White, Contribu~oes a Paleontologia do BraziJ. Archivos do Museu Nacional do Rio de Jeneiro, Vol. VII, 1887. 38. Woods, Cret. dep. Northern Nigeria.-H. Woods, The palaeontology of the upper Cretaceous deposits of Northern Nigeria. The Geology and Geography of Northern Nigeria by J. D. Falconer. London and Bungay, 1911. 39. Yabe, Cret. Ceph. Hokkaido 11.-H. Yabe, Cretaceous Cephalopoda from the Hokkaido. Part II. Jour. of the College of Science, Imp. Univ., Tokyo, 1904, Vol. 20, art. 2. 40. Yabe, Strat, u. Pal. Hokkaido.-H. Yabe, Zur Stratigraphie und Palaontologie der oberen Kreide von Hokkaido und Sachalin. Zeitschr. d. Deutsch. geol. Ges. Bd. 61, 1909. 41. Zittel, Lib. Wtiste.-K. A. Zittel, Beitrage zur Geologie und Palaeontologie der Libyschen Wtiste und der angrenzenden Gebiete von Aegypten. I. Geolo­gischer Theil. Palaeontographica Bd. 30, I. 1883. A New Ammonite Fauna of the Lower Turonian of Mexico 183 STRATIGRAPHY The Cerro del Macho is a small hill in the eastern part of the Hacienda del Moh6vano belonging to Mr. Frederick Ritter. The hacienda lies to the southeast of the station Carillo of the railway which connects Sierra Mo­jada, Coahuila with Escalon, Chihuahua (Mexican Central Railway) and part of its land belongs to the State of Chihuahua while the rest lies in the State of Coahuila. The Cerro del Macho belongs to this last region and lies near the boundary line of both states. Dr. E. Haarniann gave me the following geological cross-section of the fossiliferous locality, to which I add the stratigraphical explanation ob­tained as the result of the study of the fauna. ll, s Fig. 1 Fossil bearing beds on the Cerro del Macho, Hacienda del Moh6vano, Coahuila. III. Gray hard limestones Lower Turonian. II. Gr-ay-bluish marls } I. Yellow and red marls and argillaceous limestones Upper Cenoman­ian ( ?) . Three different petrographical horizons can be distinguished : the low est beds consist of yellow and red marls with argillaceous limestones con­taining numerous fossils, especially bivalves; this horizon which for the present we shall designate with the number I has a thickness of only two University of Texas Bulletin meters in this locality, but its base is covered. Above these marls lie gray­bluish marls with large cephalopods; the thickness of this horizon which we designate as Number II, is 2.5 meters. On top of these marls we find gray limestones with numerous cephalopods, bivalves and gastropods; the . thickness of this horizon, which we call Number III, is about 5 to 6 meters, its, upper limit being unknown. According to Dr. Haarmann the beds show a strike of N50-60°E and a dip of approximately l0°NW.1 The whole outcrop has thus only a thickness of about 10 meters, but nevertheless we find two different horizons, as will be shown in the following. Among the fossils collected in this locality I have been able to distinguish twenty-one different species which are distributed in the three horizons in the following manner : Horizon I. Metoecoceras aff. Whitei Hyatt Metoecoceras n. sp. Exogyra Haarmanni n. sp. Exogyra cfr. olisiponensis Sharpe H emiaster sp. Horizon II. Mammites mohovanensis n. sp. Pseudaspidoceras aff. Footeanum ·Petrascheck Pseudaspidoceras aff. pedroanum White Vascoceras aff. Adonense Choffat Fagesia Haarmanni n. sp. Fagesia Pervinquieri n. sp. Horizon III. Vascoceras Angermanni n. sp. Vascoceras ex. aff. Gamai Choffat Vascoceras ( ?) sp. Vascoceras mohovanense n. sp. N eoptychites aff. xetriformis Pervinquiere Hoplitoides aff. mirabilis Pervinquiere Inoceramus labiatus Schlotheim A vicula Aguilerae n. sp. Trigonia sp. Crassatella sp. Tylostoma aff. ovatum Sharpe To show the stratigraphic importance of the different species we shall have to compare them with related forms. 1According to a sketch of Dr. Angermann the strike of the beds is N-S and the dip 10 degrees W. ' .. A New Ammonite Fauna of the Lower Turonian of Mexico 185 Horizon I. Upper Cenomanian Turonian Species from Cerro del Macho Related species Metoecoceras aff. Whitei Hyatt M. Whitei Hyatt ? ? M etoecoceras n. sp. M. Geslianum Petrascheck + Exogyra Haarmanni n. sp. • Exogyra cfr. olisiponensis Sharpe Ex. olisiponensis Sharpe + + H emiaster sp. I The age of this horizon cannot be determined quite exactly. The fossils are few, the cephalopods among them indicate only that the horizon belongs either to the lower Turonian or the upper Cenomanian. Metoecoceras aff. Whitei is similar to forms found in the Colorado Formation of the United States, a division which up to now has not been subdivided stratigraphic­ally with the necessary exactness; it probably represents in its larger part the Turonian, but may possibly contain some upper Cenomanian and a por­tion of Emscherian. The portion in which "Pr!. Whitei has been found be­longs to the lower part of the formation, which is either the lower Turonian or the upper Cenomanian. Our Metoecoceras n. sp. is very similar to M. Geslianum Petrascheck,1 which occurs in the upper Cenomanian of Saxony, but we do not know exactly if our specimen has been fourid in this lowest horizon or in one a little higher. Interesting is the occurrence of an Exogyra certainly belonging to the group of Exogyra olisiponensis Sharpe. This species is found on the bor­der of the Mediterranean in the Cenomanian as well as in the Turonian, although the variety which is most similar to our specimen seems to be limited principally to the Cenomanian. Our Exogyra Haarmanni n. sp. is a new species and not very characteristic, therefore without any strati­graphic value. The Hemiaster found in the same bed can not be used for the determination of the age as it does not appear to be identical with any described species nor to be closely related to any known species which might indicate the age of these beds. The small number of fossils of this horizon does not allow an exact de­ termination of its age. Taking into consideration the radical difference be­ tween the character of this fauna and that of Horizon II, and the presence of a form of M etoecoceras very similar to the one of the upper Cenomanian of Saxony, I feel inclined to consider this horizon provisionally as upper Cenomanian until other and more characteristic fossils allow a more exact determination of the age. Much more numerous is the fauna of Cephalopods in Horizon II and iPetrascheck, Amm. d. sachs. Kreideform., 1.140 (10) pl. 7 (1); figs. 3-5. University of Texas Bulletin their forms are so characteristic that they easily allow the determination of the age of these beds. In the following table we shall compare them with related species of other countries. Horizon II. Turonian Species from Cerro del Macho Related species Lower Middle Mammites mohovanensis n. sp. M. nodosoides Schlotheim Pseudaspidoceras aff. Footeanum P. Footeanum Petrascheck + Pseudaspidoceras aff. pedroanum P. Footeanum Stoliczka + Vascoceras aff. adonense V. adonense Choffat + Fagesia H aarmanni n. sp. F. superstes Kossmat + Fagesia Pervinquieri n. sp. F. tevesthensis Peron + All the species of this horizon indicate that it belongs to the lower Tu­ronian or Salmurian. It s true that Choffat cites his Vascoceras adon­ense from the middle Turonian, but I believe that this middle Turonian of Portugal belongs in reality still to the Salmurian, i.e., the lower Turonian. The occurrence of forms belonging to the groups of Fagesia superstes, Fa­gesia tevesthensis, Mammites nodosoides, Inoceramus labiatus, etc., ap­pears to be quite decisive for the determination of the age of those beds. In our own case we have to consider that this horizon lies immediately above what we take to be upper Cenomanian; there seems to be no reason to doubt that our Horizon II represents the very lowest Turonian. This idea is confirmed also by the fauna of Horizon III, which will be discussed farther on. Our Mammites mohovanensis is very nearly related to M. nodosoides Schlotheim. It differs principally in its broader cross section; stili more similar to our species is Mammites conciliatus Stoliczka, which belongs to the same group, the main difference consisting in its more evolute form and some details of ornamentation. In these details our form is still more similar to a form determined by Fritsch as Mammites conciliatus which in reality occupies an intermediate position between our species and that of India. The species which we have called Pseudaspidoceras aff. Footeanum Pe­trascheck is much less related to the type of this group (P. Footeanum Stoliczka) than to the specimens from the lower Turonian of Saxony de­scribed by Petrascheck, on account of the more rounded and less subquad­rangular cross section, as well as the greater height of the whorl. This dif­ference may be explained in our section by its large size; comparing the different figured forms of P. Footeanum we see that the adult specimens tend to lose their quadrangular cross section. This group has been found A New. Ammonite Fauna of the Lower Turonian of Mexico 187 in the lower Turonian in many cases where an exact determination of the age of the beds has been possible. Varieties of this group have been de­scribed from India, from different parts of northern Africa, as Egypt1 and Tunis2 ; from Portugal3, from Nigeria\ from Saxony5, and from Bra­zil.6 It is therefore a universally distributed form which characterizes the lower Turonian. To the same group of Pseudaspidoceras Footeanum belongs also the species called by me Pseudaspidoceras aff. pedroanum White. It is still nearer related to the Indian type than the former species, but differs by its less strong ribs and the smooth ventral part. In all its characters it is similar to the Ammonites pedroanus White and only differs in some de­tails of the ornamentation. The similarity is so great that I have not been able to separate the two forms specifically and have not united our speci­men with the Brazilian species only because this latter form is still imper­fectly known. Our Vascoreras aff. adonense is certainly very similar to the Portuguese type from the Turonian, but differs by its suture and the form which is still more evolute. The form of greatest stratigraphic interest in our fauna is perhaps our Fagesia Haarmanni n. sp. It belongs to the group of Fagesia superstes Kossmat, but differs from the type as well as from all the other species of this genus by its more evolute form. The species belonging to this group are limited to the Turonian and especially to the lower part of it. The type was described from the Utatur group of India,7 and a very typical form has also been found in Tunis8 ; a nearly related species has been cited from the Turonian of Portugal.9 Fagesia Pervinqieri n. sp. is a very characteristic species and belongs to that group of Fagesia which loses its ribs in a rather juvenile state of growth; the type of this group is Fagesia tevesthensis Peron. Our species differs from the type by its higher and less broad whorls. A~cording to Pervinquiere Fagesia Rudra Stoliczkaio belongs also to this group; this !Zittel, Lib. Wiiste, p. LXXIX (A. cfr. Footeanus) Eck, Turon in AcgypU.n; p. ::hO (Acanthoceras cfr. Footeanum). 2Pervinquiere. Paleontologie Tunisienne, p. 314 (Mammites Salmuriensu;). 3Choffat, Especes nouv. ou peu conn., p. 66 (Acanthoceras cfr. Footeanuu;. i •Woods, Cret. dep. Northern Nigeria, p. 283 (Mammites [Pseudaspidoceras] ::;p.). oPetrascheck, Amm. d. sachs. Kreideform., p. 144 (Mammites F'orteanus). awhite, Brazil, p. ·212 (Ammonites pedroanus). 1Kossmat, Siidindische Kreideform., .p. 133, pl. 17, fig. 1. sPervinquiere, Paleontologie Tunisienne, p. 322, pl. 20, fig. 1-3. 9Choffat, Especes nouv. ou peu conn., p. 69, pl. 10, fig. 4. 1ostoliczka, Ceph. Cret. Rocks India, p. 122, pl. 60. University of Texas Bulletin species which occurs in the Utatur group of India is similar to our species on account of the missing umbilical nodules in a stage of development which still shows the ribs on the ventral part; it differs, though, by its much broader and larger whorls. Another form which by Pervinquiere is considered as belonging to the same group is Ammonites Kotoi Yabe.1 Per­vinquiere believes that this species is perhaps identical with Fagesia teves­thensis Peron, but it appears to me that we have here a different species although it is certainly related to the African form. According to Yabe2 it is not quite certain from which beds this form has been collected; it oc­curs either in the Mammites beds or in the Scaphites beds. The age of Fagesia Rudra is not well known, although Kossmat presumes that this species belongs to the middle Utatur group. FagesiaA tevesthensis charac­terizes the lower Turonian ; a very similar form exists in beds of the same age in France and another in the Turonian of Portugal. Stiil richer than the fauna of Horizon II is that of the upper limestones which we have distinguished as Horizon III. For their comparison with related species we shall again unite them in a table. Lower Species from Cerro del Macho Related species Turonian Emscherian Vascocera1 · rigermanni n. sp. F. Kossmati Choffat + Vascocerao ex aff. Gamai ·v. G(lmai, Choffat + Vascoceras (?) sp. r. (?) arnesense Choffat + Vascoceras mohovanense n. sp. V. polymorphum Pervinquiere + N eoptychites aff. cephalotus N. cephalotus Courtiller + N eoptychite.s aff. xetriformis N. xetriformis Pervinquiere + lloplitoides aff. mirabilis H. mirabilis Pervinquiere + Inoceramus labiatus Schlotheim I. labiatus Schlotheim + A vicula Aguilerae n. sp. A. gravida Coquand + + Tylostoma aff. ovatum Sharpe T. ovatum Sharpe + ( Cenomanian to upper Turonian Nearly all of the groups of ammonites cited in this list occur only in the lower Turonian, to which, according to my opinion, belong also the beds with Vascoceras of the so-called middle Turonian of Portugal. Vascoceras Angermanni n. sp. is very similar to V. Kossmati Choffat, but its form is still a little broader, there is no doubt that it belongs to the same group and this is until now only known in the Turonian of Portuga] and the lower, Turonian of Egypt.3 The fossil which we have called Vascoceras ex. aff . .Gamai Choffat is a juvenile form and not very well preserved which is very similar to the 1Yabe, Cret. Ceph. Hokkaido II, 26, pl. 6, figs. 3-4. 2Yabe, Strat. u. Pal. Hokkaido, p. 441. 3Eck, Turon in Tegypten, p. 381, 382. A New Ammonite Fauna of the Lower Turonian of Mexico 189 small individuals figured by Choffat1 in figures 3 and 4 of plate 7 and figure 2 of plate 10. Considering the size and state of preservation this specimen is not of great stratigraphic value. Vascoceras ( ?) sp. is a pretty large specimen which is very similar to Ammonites arnesensis Choffat. The generic determination is not quite certain as is also the case with A. arnesensis. Our specimen is a little twisted; it does not have much importance for the determination of the age of the beds. Vascoceras mohovanense n. sp. is a specimen relatively small but very characteristic; it belongs certainly to the group of Vascoceras polymor­phum Pervinquiere of the lower Turonian of Tunis. It differs from the type by a missing intermediate row of nodules but in its general character and also in its suture is nearly related to the type. Pervinquiere considers Vascoceras subconciUatum Choffat from the Turonian of Portugal as a form of the same group but this species is different from ours on account of its general form and its suture. The species described by me as N eoptychites aff. cephalotus Courtiller is a juvenile specimen which resembles greatly the small individuals of the cited species, as has been demonstrated in the paleontological part of this paper. The group of N eoptychites cephalotus characterizes the lower Tu­ronian; it occurs frequently in Algiers and Tunis, also in the neighborhood of Saumur, France. Similar and perhaps identical forms have been found in India (Neoptychites Teltnga Stoliczka) 2 and in Kameruni (Neoptychites Telingaeformis Solger3 ) ; the ag-e of the beds where these latter species have been found is not exactly known. The form which I compare with N eoptychites xetriformis Pervinquiere, is not very well preserved but resembles sufficiently the species from Tunis. Pervinquiere considers as a nearly related form N eoptychites crassus Sol­ ger,4 the age of this latter species is not determined with certainty. In the limestones of Horizon III we find frequently cephalopods which resemble very much the bicarinated H oplitoides of Pervinquiere. The greater part of these specimens is entirely corroded but in one I have been able to prepare a portion of the interior whorl which clearly shows the ex­ istence of the two lateral keels on the ventral portion; one also notes the suture in part, certainly much destroyed but showing the same elements as in the bicarinated Hoplitoides. A large specimen has the external form of 1Choffat, Especes nouv. ou peu conn. 2Stoliczka, Ceph. Cret. Rocks India, p. 125, pl. 62; Kossmat, Sildind. Kreideform., p. 71, pl. 7, fig. 1, pl. 17, fig. 13. ssolger,' Mungokreide, p. 108. 4Solger, Mungokreide, p. 119, pl. 3, fig. 5. University of Texas Bulletin H oplitoides mirabilis but is a little less involute. This group is of some in­terest in so far as having been found only in the lower and upper Turon­ian. The types of Hoplitoides mirabilis1 and H. Munieri2 occur in Tunis mainly in the lower Turonian, H. Munieri also in the upper Turonian. A similar species has been found also in the Turonian of Egypt.3 In the same Horizon III, Dr. E. Haarmann also collected four specimens of Jnoceramus of which three are typical individuals of Inoceramus labia­tus Schlotheim. According to an observation made by Jose· G. Aguilera, this fossil occurs in great numbers in beds north of the station of Carillo which apparently overlie limestones identical with those described here. In Horizon III occurs very frequently A vicula Aguilerae n. sp. This species is very similar to A11icula. gravida Coquand which occurs in north­ern Africa in the Turonian as well as in the lower Senonian or Emscherian. The form and size of this Avicula are so similar to those of ours that this find in Mexico has a certain stratigraphic interest. In the material of Horizon III we find a great number of other bivalves, but all in the state of internal molds; a specific determination is entirely impossible. The most frequent form probably belongs to Tylostoma or some subgenus of Natica; the greater part of the material is badly pre­served, but some specimens are a little more complete, although preserved as internal molds, and resemble strongly Tylostoma ovatum Sharpe which in Portugal occurs in beds from the Cenomanian to the upper Turonian. From the character of the fauna of Horizon III we have to conclude that these beds still belong to the lower Turonian. This appears rather proba­ ble from the circumstance that Horizon II is extremely thin and is well confirmed especially by the cephalopod fauna. Interesting is the occur­ rence of Inoceramus labiatus Scholtheim. This fossil is extremely common in Mexico and generally is found in great numbers in calcareous shales and shaly limestones. The question now is, what relation exists between those beds and those of Cerro del Macho? In the described locality the shales, etc., do not exist, but according to the identification of J. G. Aguil­ era these are found north of the station of Carillo where they apparently overlie limestones similar to those of the Cerro del Macho. If we accept this explanation, our beds at Cerro del Macho have to be considered as the· lowest part of the Turonian, while the shales with Inoceramus labiatus would be a little younger and perhaps represent the lower as well as the upper Turonian. We have no data with which to solve this problem, as up to now the beds with Inoceramus labiatus have not been found in contact 1Pervinquiere, Paleontologie Tunfaienne, p. 218, pl. 10, fig. 3. 2Jdern, ibid., p. 217, pl. 10, figs. 1, 2. 11Eck, Turon in Aegypten, p. 380, 386. A New Ammonite Fauna of the Lower Turonian of Mexico 191 with the cephalopod beds described here; neither have those beds with Ino­ceramus labiatus been found in immediate contact with fossiliferous beds of the Emscherian. Only in one place, Opal, Zacatecas, I have found beds with lnoceramus labiatus (rare) and /. hercymicus (very frequent) in contact with sandstones containing an Inoceramus nearly related to lnoce­ramus cycloides, but the cross section of this locality is too incomplete and the fauna too poor for a decision of this rather important problem. The locality of Cerro del Macho is stratigraphically important in so far as it gives us some data for the limitation of the upper Cenomanian and the lower Turonian. In a former work we have been able to subdivide the Cenomanian of Cerro de Muleros near Ciudad Juarez, but we have not been able to find fossils in the sandstones between the beds with lnoceramus labiatus and the marls with Hemiaster Calvini; thus it was impossible to decide if those sandstones belonged to the Cenomanian or the Turonian. In the present case we have very fossiliferous beds very near the limit be­tween the Cenomanian and the Turonian. The fossils of the Cenomanian are very different from those found up to the present in Cenomanian rocks of Mexico. Of especial importance is the occurrence of Metoecoceras. The Turonian ammonite fauna is also entirely new for Mexico, the few ammonites so far found in the beds with lnoceramus labiatus belonging to entirely different groups. Haarmann has distinguished two horizons, II and III, but these do not appear to be more than local subdivisions notwithstanding the circum­ stance that the fauna of the two beds seem to be rather different. We must not give too much importance to this circumstance, as the collections so far made are still rather small and the aspect of the fauna may change alto­ gether with larger collections made. As far as we can see, the lower bed contains principally cephalopods while in the upper one bivalves and gas­ tropods predominate. With respect to the conditions of life in this locality we may say with some certainty that at the end of the Cenomanian in the Cerro del Macho region as well as in others of northern Mexico, especially in the State of Chihuahua, there exjsted a littoral fades or at least a very' shallow sea; this is indicated by the great quantity of Ostreidae which nearly form beds or which have been carried away from neighboring beds. At the begin­ ning of the Turonian age the sea seems to have deepened a little, the pre­ dominance of the ammonites and the absence of littoral bivalves indicating a less shallow sea. It is probable that during the time of the deposition of the upper part of the Salmurian the sea again became a little shallower; this is indicated by the predominance of Lamellibranchia and Gastropoda with thick shells, but the facies is not quite as much a littoral one as in University of Texas Bulletin Cerro del Muleros near Ciudad Juarez at the same time, where the corre­sponding beds consist entirely of sandstones. According to the observations of Haarmann and our palaeontological studies the stratigraphical cross section of the Cerro del Macho presents the following features : 5-6 m. of gray limestones with: Vascocerr,is Angermanni n. sp., V . ex a!f. Gamm Choftat, Vase. sp., V. mohovanense n. sp., Neoptycldtes aff. ce.µhc.­lotus Courtiller, N . aff. xetriformis Pervinquiei-e, H 1Jpl·i­toides aff. mirabilis PervinquierP,, lno:;cramus labiatt1 !' Schlotheim, A vicula Aguilerae n. sp., Tngonia sp., Cras­satella sp., Tylostoma aff. ovatum Sharp.;, (Lamellibran­chia and Gastropoda extremP.Jy fr~·quent). 2.5 m. of gray-bluish mar!s with: Mammites mohovanensis n. sp., Pseudaspidoceras aif Footeanum Petrascheck, Ps. aff. pedroanum White, VaSLO­ceras aff. adonense Choffat, Fagesia Haarmanni n. sp F. Perviniquieri n. sp. 2 m. yellow and reddish marls and limestones with: Metoecoceras aff. Whitei Hyatt, Metoeco'Jcras n<.1v. sp., Exogyra Haarman11i n. sp., Ex. cfr. uted in a modern manner. we should not g-ive too much im­portance to the age which has been assigned to a certain species from In­dia. We should always take into account that in such old collections labels 1Stoliczka, Ceph. Cret. Rocks India. pl. 61, fig. 2. A New Ammonite Fauna of the Lower Turonian of Mexico 225 may have been changed and that the fossils frequently have not been col­ lected with the necessary exactness. Number of specimens : 1. Age: Lower Turonian (Salmurian) , lower horizon. HOPLITOIDES V. Koenen Emend. Solger et Pervinquiere The genus Hoplitoides has been established by von Koenen1 for certain ammonites from the limestones of the Mungo in Kamerun; later Solger2 studied the same fauna and made the definition of the genus more precise. Then Pervinquiere1 amplified this definition still more and distinguished two groups within the genus Hoplitoides: the bicarinate and the monocar­inate forms. The first group seems to be limited to the Turonian, the sec­ond one to the Emscherian. Among our material we find a few ammonites which very probably be­long to the first group, the bicarinate H oplitoides. The specimens are not very well preserved and the generic determination is not entirely certain. The external form corresponds completely with that of the H.oplitoides, but the suture is much destroyed and scarcely permits recognition of the general character of the line; this, however, coincides entirely with the suture of the bicarinate H oplitoides. The character of the suture on the other hand shows that the specimens do not belong to Placenticeras, a genus which externally is quite similar to H oplitoides. HOPLITOIDES aff. MIRABILIS Pervbquiere Pl. 19, figs. 1-3 . l.907: H oplitoides mirabilis Pervinquiere, Paleontologie Tunisienne, p. 218, pl. 10, fig. 3 Among the material placed at my disposition I found two relatively complete specimens and four fragments which, according to their suture and external form, belong to the so-called Pseudoceratites of the Creta­ ceous. The best preserved specimen shows the following features: Shell discoidal, entirely evolute, with whorls of lanceolate cross section truncated at the point, much higher than broad. The umbilicus is very narrow, the umbilical wall is vertical and the umbilical border rounded. The flanks are smooth, very little convex, nearly flat. The venter is flat with a sharp shoulder on each side; on the internal whorl we observe on both shoulders of the venter a sharp keel and the zone there is concave. iv. Koenen, Nachtr. Foss. Mungo i. Kamerun, p. 53. 2solger, Mungokreide, p. 127. 226 University of Texas Bulletin The suture is badly preserved, because all the specimens are corroded on the surface, and no suture could be made visible on the internal whorls. We note a little ramified external saddle, which is rather broad and low; the first lateral lobe is broad, shallow and ends in three points, those on the umbilical side being longer than the one on the ventral side. Some smaller ramifications exist on the sides of this lobe. The first lateral Figure 7. Sutures, N eoptychites aff. xetriformis Pervinquiere (lower left hand corner) and H oplitoides sp. (other three). saddle is broad and relatively high, and a secondary lobe divides it in two parts. The following saddles are much destroyed and no longer show their ramifications. The lobes are much shallower than the first lateral lobe. Dimensions : Diameter . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . 149 mm. (1) 119 mm. (1) Height of the ·1ast whorl·. . . . . . . . . . . . . . . . . . . . . 76 mm. 0.51 58 mm. 0.49 Width of the last whorl. . . . . . . . . . . . . . . . . . . . . 45 mm. 0.30 34 mm. 0.29 Diameter of the umbilicus. . . . . . . . . . . . . . . . . . 19 mm. 0.13 18 mm.? 0.15 Our specimens belong very probably to the genus H oplitoides and to the bicarinate group of it. Externally they resemble this group in an extra­ordinary manner and especially H oplitoides mirabilis Pervinquiere. Per­vinquiere has united these forms, which distinguish themselves·by a flat venter even in a very advanced stage, with the H oplitoides of the Emsche­rian, which show a flat venter only in their youth, the venter in the adult age becoming sharp or a little rounded. Only the study of a large and A New Ammonite Fauna of the Lower Turonian of Mexico 227 rich material could decide if it would not be better to separate these two groups at least subgenerically. It was probably the want of sufficient ma­terial which decided Pervinquiere not to separate the two Turonian species from the rest of the genus. If such study should prove that all the species from the Turonian belong to the bicarinate group, it would be better to unite them in a different species. The main difference between our species and H..mirabilis consists prob­ably in the larger diameter of the umbilicus, but our material is not suffi­ciently well preserved to allow a more detailed comparison. The two species of bicarinate H oplitoides described by Pervinquiere oc­cur in the lower Turonian ; one of them has also been found in the upper Turonian (H. Munieri). Eck1 cites with some doubt Hoplitoides mirabilis, or a similar form, from the Turonian of Egypt. Woods2 describes a Hoplites Nigeriensis from Ni­geria which he takes to belong to the bicarinate H oplitoides. These spec­imens occur in p~obably Turonian beds. In the same locality have been found· Vascoceras Gongilense Woods and Pseudaspidoceras sp. Woods mentions that H oplitoides has also been found in another locality of Ni­geria. Number of specimens : 2, and 4 fragments. Age: Lower Turonian (Salmurian), upper horizon. LAMELLIBRANCHIATA AVICULA Bruguiere AVICULA AGUILERAE sp. nov. Pl. 20, figs. 1-2, 11-12 The material from the upper horizon of the Salmurian of Cerro del Macho contains a number of specimens of a large and well characterized Avicula. Its features are: Shell thin, of subquadrate form, nearly as high as broad, not very con­vex; the right valve is a little more convex than the left one. On the an­terior side is a prolongation in form of an auricula which is not quite com­pletely preserved but which certainly was not very long; on the posterior side we note a prolongation in form of a wing, with a precise limit be­tween this wing and the rest of the shell. The auricula as well as the wing 1Eck, Turon in Aegypten, p. 382 and 386. 2woods, Cret. dep. Northern Nigeria, p. 284, pl. 23, fig. 3; pl. 24, figs. 1-5; fig. 1 of the text. ... 22S University of Texas Bulletin form with their superior border approximately the prolongation of the cardinal border and do not elevate themselves above the beaks. The beaks are small and pointed. The cardinal border is straight, long, and vertical in relation to the longitudinal axis of the shell. The surface of the shell is entirely smooth and shows only fine concentric striae of growth. All ou·r specimens are internal molds but some have preserved remains of the shell. Our very characteristic species resembles Avicula gravida Coquand.1 The main difference seems to consist in the greater convexity of the valves in this latter species, also in the different position of the beaks in relation to the upper border of the auricula and the cardinal border; but it is possible that this last difference may be explained as an error of the draftsman, because Coquand mentions expressly that neither the auricula nor the pos­terior wing elevate themselves above the beaks. In every case our species is nearly related to the African one. Coquand mentions that his species occurs in the Turonian (Mornasian) ; later on Peron2 corrected this determination of the horizon. He says that he has always found this species in the Santonian, at the vase of the Se­nonian, in the beds with Buchicera.s and Hemiaster Fourneli. But not­withstanding this correction it is possible that Coquand was right in his determination of the horizon, because Pervinquiere3 also mentions that he has found A vicula gravida in the lower Turoman. The species seems to occur also in the Emscherian, from which horizon it is cited by Pervin­quiere4 who has also found it at the base of the Senonian immediately above the Turonian. The species thus probably lived from the Salmurian to the Senonian; it is of course possible that the specimens found in the different horizons really were different species, although these certainly belong to the same group. At first view, one might believe that our species are identical with Avi~ cula pedernalis Roemer1 but A i•icula Aguilera does not have the singular scars of that species, which remind us of those of M eleagrina. Roemer has figured them and I have observed them also on a specimen from the Vraconian of Arivechi, Sonora. The general form of Roemer's species is also a little different from ours. Number of specimens: 6. Age: Lower Turonian (Salmurian), upper horizon. 1 Coquand, Geol. et Pal. de Constantine, p. 216, pl. 13, figs. 17, 18. 2 Thomas et Peron, Hauts-Plateaux de la Tunisie, p. 241. 3Pervinquiere, Et. geol. Tunisie, pp. 101, 108. 1Pervinquiere, Et. geol. Tunisie, p. 115, 117, 151, , A New Ammonite Fauna of the Lower Turonian of Mexico 229 INOCERAMUS Sowerby INOCERAMUS LABIATUS Schloth-eim Pl. 20, fig. 5 1813: Oxtracites labiatus Schlotheim in Leonhard"s min. Taschenb. VII p. 93, fidi~ Geinitz. 1875: Inoceramus labiatus Geinitz, Elbtha1gebirge II, p. 46, pl. 12 cum syn. 1893: Inoceramus labiatus Stanton, Colorado Form., p. 77, pl. 10, :fig. 4; pl. 14, fig. 2 cum syn. 1903: Inoceramus labiatus Petrascheck, Inoc. a. Kr. Bohmens, p. 156. In the upper horizon of the Salmurian of Cerro del Macho, Dr. Haar­mann found four lnoceramus of which at least three are typical lnoceramus labiatus Schlotheim. They are relatively small individuals but are en­tirely identical with those from Parras, Mexico, and different European localities. I have discussed this species extensively in Boletin 30 of the Instituto Geol6gico de Mexico; a detailed description of the specimens found on Cerro del Macho does not seem to be necessary. The occurrence of this species at our locality is of some importance because the determination of the age of the Mexican Turonian beds up to the present is entirely founded on bivalves, especially lnoceramus, and this class of fossils is always stratigraphically of less value than the cephalopods. My former determinations are now confirmed by the oc­currence of lnoceramus labiatus together with typical ammonites of the lower Turonian. Up to the present, lnoceramus labiatus has not yet been found in the lower beds of our Salmurian; it only occurs in the upper one, and even there it is not very frequent. Of course we can not yet draw any con­clusions from this distribution. The stratigraphical conditions of the region of Moh6vano should first be studied with care, larger collections from the lower horizons should be made, so as to show if Inoceramus labiatus really does not appear in those beds; and finally the relation be­tween the cephalopod beds and the shales with' Inoceramus of other re­gions of northern Mexico should be ascertained. Number of specimens : 3 ( 4?) . Age: Lower Turonian (Salmurian), upper horizon. University of Texas Bulletin EXOGYRA Say EXOGYRA HAARMANNI sp. nov. Pl. 18, figs. 4-8 In the lowest beds of Cerro del Macho numerous specimens of an en­tirely smooth Exogyra have been found. This species resembles to a certain degree Ex. columba Lamarck but is not completely identical with it. Its character is: Larger valve thin, very convex, especially in the central portion, thus forming a kind of rounded crest which goes from the beak to the lower margin. This crest gives the shell an asymmetric aspect because it is not entirely in the center, but a little nearer the anterior margin; this asym­metry is particularly noted in large specimens and much less in juvenile individuals. The beak is quite slender, spirally coiled at its point. The valve is broad, without forming wings and without a furrow in any of the sides. From the above mentioned crest the shell slopes rapidly toward the anterior margin and slowly toward the posterior margin. The sur­f ace is entirely smooth, showing only fine striae of growth and in a large specimen there is an indication of two slight concentric ridges, certainly produced by the manner of growth. The smaller valve is nearly flat. In none of the specimens is the surface entirely preserved and a detailed description of this valve can not be made. Our species resembles Ex. columba Lamarck but is much smaller and never shows a radial ornamentation, and the rounded crest is nearer to the anterior margin while in the European species it is nearer the posterior one. In its shape our species resembles still more Ex. columbella Meek,1 especially on account of the position of its crest, but the radial ornamenta­tion of that species is entirely missing in ours. Number of specimens: 12 and numerous fragments. Age: Upper Cenomanian ?, lower beds of Cerro -del Macho. EXOGYRA cfr. OLISIPONENSIS Sharpe 1850: Exogyra olisiponensis Sharpe, . Secondary Distr. of Portugal, p. 185, pl. 19, figs. 1, 2. 1911: Exogyra olisiponensis Woods, Cret. dep. Northern Nigeria, p. 278, pl. 20, figs.1-3, cum syn. In the upper part of the marls which we beli~ve belong to the Ceno­manian, Dr. Haarmann found a fragrpent of a large Exogyra. This 1 Stanton, Colorado Form., p. 63, pl. 8, figs. 2-4. A New Ammonite Fauna of the Lower Turonian of Mexico 231 species is distinguished by a moderately broad and coiled beak which slopes quickly toward the anterior margin; this steep slope continues on the valve itself, while toward the posterior margin the valve slopes in a very regular curve. The ornamentation consists of radial, thick, and not very numerous ribs. Where these are crossed by specially strong concentric lamellae of growth, a kind of prolongations is formed which nearly re­semble spines. The shell itself is very thick. The specimen does not seem to be very nearly related to the Exogyra with radial ribs, of the Mexican middle and upper Cretaceous (Ex. Whit­neyi, Ex. costata, etc.) but much more to the varieties with few ribs be­longing to the group of Ex. Olisiponensis from the border of the Med­iterranean. Our :fragment is especially similar to an individual from the Cenoma­nian of Wadi Am Rimpf figured by Fourtau1 ; this specimen shows a very similar ornamentation. Very similar also are some specimens from Deba Habe in Nigeria figured by Woods ; these show particularly the strongly sloping region of the shell toward the anterior margin. Exogyra olisiponensis occurs in the Cenomanian as well as in the Turo­ nian. Many authors certainly take the species in a very wide sense and . we do not yet know if it is possible to separate specifically the form of the Cenomanian from that of the Turonian. In general it seems to me that our specimen resembles more the varieties figured from the Cenomanian (compare among others Lartet, Geol. de la Palestine, pl. 11, fig. 1) than those from the Turonian. With this view the layer in which our specimen has been found coincides 'well; it occurs in the upper part of the marly limestones directly below the Salmurian of Cerro del Macho. We have considered these marls with some doubt as upper Cenomanian. Unfortu­nately we do not know the exact stratigraphic position of the individuals from Nigeria. Woods presumes that they come from the Turonian, be­cause in Gongila, in Nigeria, not only typical cephalopods of the Turonian (Vascoceras, Pseudaspidoceras, bi-carinated Hoplitoides) have been found, but also specimens of Exogyra olisiponensis, while in Deba Habe only Ex. olisiponensis has been collected. A solution of this problem is im­possible for the moment, but there is the possibility that at Deba Habe the Cenomanian might be represented by beds with Ex. olisiponensis. Number of specimens: 1. Age: Upper Cenomanian ( ?) , upper part of the lowest horizon of Cerro del Macho. 1Fourtau, Faune cret. d'Egypte, p. 287, fig. 5. University of Texas Bulletin GASTROPODA TYLOSTOMA Sharpe TYLOSTOMA aff. OVATUM Sharpe Pl. 20, fig. 3 1849: Tylostoma ovatum Sharpe, On Tylostoma, p. 379, pl. 9, figs. 7, 8. In the upper horizon of our Salmurian numerous specimens of gastro­pods have been collected; among these Tylostoma or similar genera seem to predominate. The greater part consists of internal molds which are badly preserved. In some specimens we note that the labrum is thick­ened on the inner side, thus these individuals very probably belong to Tylostoma. It is very possible that there are different species in the col­lection but in consideration of the bad state of preservation of the ma­terial it is impossible, to distinguish them with certainty. The best speci­men, as well as some less well preserved, has much similarity with T. ova­tum Sharpe. Its features are: Shell subglobose, of broad oval form, with a low spire of approximately six coils, mouth suboval and relatively narrow, labrum having an inner thickening. The surface is entirely smooth. According to Choffat1 T. ovatum occurs in all the beds from the Bella­sian to the upper Turonian; it is thus not very surprising that a similar form is found in our beds. Number of specimens: 5 and probably numerous fragments. Age: Lower Turonian (Salmurian), upper horizon. ECHINODERMATA HEMIASTER Desor HEMIASTER sp. Pl. 20, figs. 6-10 In the lower marls of Cerro del Macho, Dr. Haarmann found a Hemiaster which probably represents a new species. He found another specimen loose below the hill which seems to belong to the same species~ but it is too badly preserved for determination. The features of the better pre­served specimen are : 1Choffat, Syst. cret. Portugal II, p. 190. A New Ammonite Fauna of the Lower Turonian of Mexico 233 Shell of small size, little convex; slightly polygonal· in the ambitus, thin­ning toward the back and toward the front, the greatest width lying far in front of the center of the shell; slightly notched in front and truncated behind. The upper face is convex, the ambitus rounded, the lower face is nearly flat, a little thickened on the plastron and slightly depressed in the region of the peristome. The impair ambulacrum lies in a relatively broad and moderately deep furrow which begins in the apex and from these regularly widens toward the ambitus, narrowing from there to the peristonie; the furrow notches the contour considerably. The zones of pores are composed of pairs of small, nearly circular pores; the pores of each pair seem to be separated by a slight thickening. The zone is wide and nearly smooth; large tuber­cles are missing there and only the fine granulation can be observed. The zopes of pores occupy less than half the furrow between the apex and the ambitus. Farther on follow pores separated by larger intervals and of an oblique. position, arranged in such a manner that the pairs of the two zones alternate. The exact number of these pairs could not be counted. The anterior paired ambulacra are moderately large and of lanceolate form; they lie in relatively deep furrows. The poriferous zones are broad and consist of pairs of elongated, nearly equal pores; the pores of each pair are connected by a very distinct furrow. The interporiferous zone is rela­tively narrow and has not quite the width of one of the poriferous zones. The posterior paired ambulacra are a little shorter than the anterior ones. The poriferous zones consist of pairs of elongated nearly equal pores; the pores of each pair are connected by a slight furrow. The in­terporiferous zone is rather narrow and less wide than each of the porif­erous zones. Outside of the petals the pores are smaller and the pairs are separated by large intervals. On the whole surface of the interambulacra we observe apparently cren­ulated and perforated tubercles, enclosed by narrow areas and very near together; they are stronger on the anterior portion than on the posterior one. In the interporiferous zones of the ambulacra of the upper face, tubercles do not seem to exist. In the ambulacra of the lower face tuber­cles are infrequent, while the interambulacra of the same face are densely covered by tubercles, especially the plastron ; they decrease in size from the center toward the outside. The whole surface of the shell is covered by a fine granulation. The impair posterior inter-ambulacrum of the upper face has a sharp crest which is higher than the apicial apparatus. The anterior interam­bulacra of the same face show much less pronounced crests ; the lateral interambulacra are flattened on the center, the flattened zone being lim­ University of Texas Bulletin ited by well marked borders. These margins and the crests of the other interambulacra give the polygonal contour to the :figure of the shell. The peristome is small and of subpentagonal form. Its position is ex­centric toward the front; the lip is rather prominent. The periproct is not well preserved, but is of oval form and lies in the upper part of the posterior face. The apicial apparatus is relatively large, the two posterior pairs are widely separated from the anterior ones; the details can not be clearly recognized. Dimensions: Antero-posterior diameter . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . 27.8 mm. Transversa] diameter ... . ...... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27.3 mm. Height . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.0 mm. Distance between the apex and the posterior margin. . . . . . . . . . . . . . . . . . . . . . 16.2 mm . .. Our species is not very characteristic but I have not found one with which it might be identified entirely. It resembles to a certain degree Hemiaster Meslei Peron et Gauthier,1 but in this species the posterior am­bulacra diverge much more than in ours, the contour is more notched in front, the furrow of the impair ambulacra is much narrower and deeper. As we have not more than one well preserved individual I only describe and figure it without giving a new name to this species, or identifying it with a known one. Number of specimens : 2. Age: Upper Cenomanian ( ?) , lower horizon of Cerro del Macho. 1Cotteau, Peron et Gautheir, Ech, foss. de l'Algerie IV, p. 102, pl. 2, lgs. 5-8. PLATE 12 Metoecoceras, F agesia, Mammites University of Texas Bulletin Metoecoceras, Fagesia, Mammites. Plate 12 Figures 1, 2, 3. Metoecoceras sp. nov..................................page 205 Upper Cenomanian (?) or lower Turonian. Cer:-o ael .Macho, Hacienda de Moh6­vano, Coahuila. Fig. 1. View from the opposite side from Figure 3. Fig. 2. Venter of the same specimen. Fig. 3. Side view. Figures 4, 7. Metoecoceras aff. Whitei Hyatt........ ....................page 203 Upper Cenomanian ( ?) , lower horizon of Cerro del Macho, Hacienda de Moh6­vano, Coahuila. Fig. 4. Venter. Fig. 7. Side view. Figure 5. Fagesia Pervinquieri sp. nov ................................page 212 Lower Turonian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Venter and cross-section. Figures 6, 8. Mammites mohovanensis sp. nov ...........................page 206 Lower Turonian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Fig. 6. Cross-section and venter. Fig. 8. Side view. University of Texas Bulletin No. 1856 Plate 12 PLATE 13 Pseudaspidoceras University of Texas Bulletin PLATE 13 Pseudaapidoceraa P'late 13 Figure 1. Paeudupidoceraa aff. Pedroanum White sp.. .. ..................page 209 Lower Turonian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Side view. University of Texas Bulletin No. 1856 Plate 13 PLATE 14 Fagesia, Vascoceras University of Texas Bulletin PLATE 14 Fagesia, Vascoceras Plate 14 Figure 1. Fagesia Haarmanni sp. nov ............. ..................·....page 211 Lower Turonian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. View of the other side of the specimen figured as Fig. 2, Pl. 15. Figure 2. Fagesiia Haarmanni sp. nov................ ...................page 211 Lower Turonian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Cross-section and venter of specimen figured as Pls. 15 and 14. Figure 3. Fagesia Pervinquiri sp. nov...................................page 212 Lower 'l'uronian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Side view of specimen figured on Pl. 12, fig. 5. Figure 4. V1ascoceras n. sp. ex. aff. V. adonense Choffat.................page 214 Lower Turonian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Cross-section and venter. University of Texas Bulletin No. 1856 Plate 14 I ~ I ·I PLATE 15 Pseudaspidoceras, F agesia, Vascoceras Unive?'Sity of Texas Bulletin PLATE 15 Pseudaspidoceras, Fagesia, V.ascoceras Plate 15 Figure 1. Pseudaspidoceras aff. Pedroanum Whit-a sp .....................page 209 Lower Turonian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Cross-section and venter. Figure 2. Fagesia Haarmanni sp. nov ...................................page 211 Lower Turonian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Side view. Figures 3, 4, 5. Vascocer:as aff. Gamai Choffat...... ....................page 216 Lower Turonian, probably from upper horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Figs. 3 and 5, view of both sides. Fig. 4. Cross-section and venter of the same specimen. Plate 15 University of Texas Bulletin No. 1856 PLATE 16 Vascoceras 244 Uniuersity of Texas Bulletin PLATE 16 Vaacoceraa Plate 16 Figures 1, 2, 3, 4. Vaacoceraa Angermanni sp. nov .....,......... ... ......page 217 Lower Turonian, upper horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Fig. 1. Side view. Fig. 2. Cross-section and venter of, specimen figured on Fig. 4. Fig. 3. Cross-section and venter. Fig. 4. Side view of a larger specimen. University of Tex.as Bulletin No. 1856 Plate 16 • PLATE 17 Vascocer~s University of Texas Bulletin PLATE 17 V:s.scoceras Plate 17 Figure 1. V1ascocer'las Angermanni sp. nov ..... ..........................page 217 Lower Turonian, upper horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Side view of a large specimen. Figure 2. Vascoceras n. sp. ex. aff. V. adonense Choffat. ..................page 214 Lower Turonian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Side view of the specimen figured on Pl. 14, fig. 4. Plate 17 University of Texas Bulletin No. 1856 PLAJ'E 18 V ascoceras, Neoptychites, Exogyra f University of Texas Bulletin PLATE 18 Vascoceras, Neoptychites, Exogyr>a Plate 18 Figures 1, 2. Vascocer>as Mohovanense sp. nov ............ ........ .......page 219 Lower Turc:mian, lower horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Fig. 1. Side view. Fig. 2. Cross-section and venter. Figures 3, 13, 10. Neoptychites aff. Cephalotus Courtiller. .. . .. .... . ......page 221 Lower Turonian, upper horizqn. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Fig. 3. Side view. Fig. 13. Cross-section and venter of the external whorl of the same specimen. Fig. 10. Cross-section and venter of the inner whorl. Fiures 4, 5, 6, 7, 8. Exoyl'la Haarmanni sp. nov ..........................page 230 Upper Cenomanian ( ?) . Lowest horizon of Cerro del Macho, Hacienda de Moh6­vano, Coahuila. Fig. 4. Side view. Fig. 5. Side view. Fig. 6. Small valve. Fig. 7. Large valve. Fig. 8. Large valve. Figures 9; 11. Neoptychites aff. Xetriformis Pervinquiere ....... . .........page 223 Lower Turonian, upper horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Fig.. 9. Cross-section and venter. Fig. 11. Side view. Figure 12. Vascoceras sp ... . ............. . ...... . .... . .............page 218 Lower Turonian, upper horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Side view. Plate 18 University of Tex.as Bulletin No. 1856 PLATE 19 Hoplitoides University of Texas Bulletin PLATE 19 Hoplitoides Plate 19 Figures 1, 3. Hoplitoides aff. mirabili.s Pervinquiere . .. ..................page 225 Lower Turonian, upper horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Side view of two specimens. Fiure 2. Hoplitoides aff. mirabilis Pervinquiere ..........................page 225 Lower Turonian, upper horizon. Cerro del Macho, Hacienda de Moh6vano, Coahuila. Cross-section and venter of specimen figured on Fig. 3. University of Tex.as Bulletin No. 1856 Plate 19 PLATE 20 Avicula, Tylostoma, Exogyra, lnoceramus, Hemiaster University of Texas Bullel'in PLATE 20 Avicula, Tylostomia, Exogyra, lnoceramus, Hemiaster. Plate 20 Fiures 1, 2, 11, 12. Avicula Aguilerae sp. nov ..........................page 227 Lower Turonian, upper horizon. Cerro del Macho, Hacienda del Moh6vano, Coahuila. Fig. 1. Left valve of specimen. Fig. 2. Left valve. Fig-. 11. Cardinal margin of same specimen. Fig. 12. Anterior side. Figure 3. Tylo.stoma aff. ovatum Sharpe ........... ...................page 232 Lower Turonian, upper horizon. Cerro del Macho, Hacienda del Moh6vano, Coahuila. Figure 4. Exogyra cfr. olisiponensis Sharpe............................page 230 Upper Cenomanian ( ?) Lowest horizon of Cerro del Macho, Hacienda del Moh6­vano, Coahuila. Figure 5. lnoceramus . labiatus Schlotheim ........ .....................page 229 Lower Turonian, upper horizon. Cerro del Macho, Hacienda del Moh6vano, Coahuila. Figures 6, 7, 8, 9, 10. Herniaster sp . . . . . . . . . . . . . . . . . . .................page 232 Upper Cenomanian (?). Lowest horizon of Cerro del Macho, Hacienda del Moh6­ vano, Coahuila. Fig. 6. Front. Fig. 7. Posterior side. Fig. 8. Left side. Fig. 9. Lower face. Fig. 10. Upper face. University of Texas Bulletin No. 1856 Plate 20 _J IN DEX .f'ig11re:; "' italics n<'r>ote aescr1ption of species. Abbreviations, tables of fossiJs ______46, 61, 55, 5< Acanthoceras -------------------________201, 221 cfr. Choffati KossmM ------------·--_________ 197 neptuni ------------------------------------197 prenodosoides b. L. & l'. __ ---------·-----··--61 sp. ------------------------------------____ 44 11ubvicinalc Bou'.e, Lemoine and Thevenin__ __ ___ _________________ __ __ _________67, 202, 203 vicinale Stoliczka _______ _-------_________ ___t02 worthen.•c n . sp. ____________ __ _____ _____,,:], 150 Acompsoceras ----------------·--------------.201 Adkins, W. S. -----------_____________ l:.::, l •l!i, 1·17 Africa, northet':1 ··----------·--·--·· --· --------·---4.2 limonite and pyrite la1ma nf_ _______________ 54, 65 Turonian of ------· . ·-____________ ___ ____20~. 209 Aguilera, Jose G. ___ .. _____ ___ ---·------. ,.-190, Hl2 Albian, correlation of -----· -----------______ lh fauna of -------··--····--···--------·----64, 65, !:6 Algeria -----------·-------··----------4~. 214, 223 fauna of -----------··----_ -··----__________ 66, 194 Salmurian of ____ ·-... -----------·-----------_194 Algiers -----------------------··--··--------6fl, 189 Alpine-Terlingua road ------· ·-----··-----··-----60 Amberleya .Qraysonensis -··------·-------· _/.17, lf.0 Ammonite fauna, Low.:r Turonian .. ···---·------179 Ammonites, description of species______69, et. seq. pyritic or limonitic____________ 44, 59, 60, 64, 65 tabulation of -----------------------------1a Ammonites acceleratum Hyatt ----------______:lOl arnesensis Choffat ______________________189, 219 conciliatus Stoliczka _____.___________________208 Geslianus d'Orbigny ____________________202, 20!; gibbosum Hyatt -----------_________________201 Harttii Hyatt ------------------------------198 Kanabense Hyatt ___________________________ 201 Kotoi Yabe ---------------------------------188 leonensis Conrad ---------------------------211 Loewianus White ___ ________________________208 offaccinatus White _____________________199, 221 pedroanus Kossmat -------------------------210 pedroanus White ------------------187, 198, 199 SwaUovi Shumard --------------------------200 l'Vhitei Hyatt -------------------------------201 Anchura mudgeana White ----------------139, 169 Ancycloceras bendirei n . sp. ______________70, 170 lineatus Gabb ------------------------------71 matheronianum d'Orbigny ------------------71 Angermann, Dr. Ernst______ l 79, 184, 217, 218, 223 Aptian, co.rrelation of ------------------------10 Aptian-Gault _____ -----------__ -----_-----____l 99 Aptien age -----------------------------------42 Aquitania, cephalopods of ---------------------197 Arca________________________23, 2~ 28, 29, 32, 33 wa.qhitaen.•is n. sp. __________________ 54, 121, 168 Arivechi, Sonora -------__ ----------_______25, 228 Armstrong Iron Works -----------------------47 Asia, Turonian of ___ ___ __________________ ___ _208 Asterisk, explanation of -----------------------45 Asteroidea -----------------------------------95 Atoka, Oklahoma -----------------------------22 Austin, Texas __ _____ ___________________ 19, 58, 68 Australia, fauna of --------------------------198 Avicula aguilerae n. sp. ______________ 190, 227, 252 gravida Coquand __ ____ _____ _______ 180, 190, 228 pedernalis Roemer ___________ ___ _________ ___ 228 Baculites comanchensis n. sp. _____________74, 152 Bailey County, Texas ----------------·---------25 Bandera road ---------------------------------59 Baptist Seminary, Fort Worth__ __ ________ ___ _ 51 Barroisiceras ( ?) Fleuriausianum d'Orbig ny______l97 Belemnites fibula Forbes ---------------------67 Bend arch ------------------------------------14 Bennington, Oklahoma ----~------------17, 19, 28 Benton formation ____ __________ _______________ 200 Berry, E. W. -----------------------------44, 146 Bibliography, Ammonite Fauna of Lower Turo­ nian of l\fexico ______________________i80-183 Weno and Pawpaw Formations of Texas Comanchean __________________ ______ 146-147 Blayac, J. ------------------------------------65 Blue l\found, Tarrant County____________ 21, 33, 55 Blum, Texas ___________________12, 23, 25, 40, 54 Rochianite.q Lory -----------------------------75 Bohemia, fauna of __ ____________ __ ____________197 Bokchito, Oklahoma ____________________17, 19, 28 creek --------------------------------------29 formation ----------------------------28, 29, .tecas --------------------------flll -Vracnnian of ______________________________ _200 l;amn Bullis. Texas ---------------------------14 C:arillo, l\fexico ___________________________ 183, 190 Cedar Creek ----------------------------------54 C:edar Hills ----------------------------------31 Cedar l\fills. Texas __________________________12, 1!l Celendin. Peru -------------------·-----··-------199 Cenomanian________l 79, 190. 1!12, 200, 230, 231, 234 corr~ation of -------------------------------10 fauna --------------------------------42, 66, 67 of Diego-Suarez __________________ ___________203 of Saxony _____________________ ____ 201, 205, 2fl6 of lfnited States ____ ________________________20n Cephalopoda ----------------------------------1\8 Cerithium ------------______ ------------______ 29 Cerro del Macho________l79, 190, 191, 192, 214, 218 Cenomanian of _____ _______________ 205, 230, 234 fauna of --------------------------192, 200, 203 fossil-bearing beds of____ _____ _____ __ __ __ __ __18~ marls of ___________________________________ 232 Salmurian of__________ l93, 211, 216, 227, 229, 231 Turonian of _____________ __________ ____208. 209 Cerro de Muleros, N. M. ___ _16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 35, 41, 42, 191, 192, 200 Chihuahua_________________________ l8, 23, 183. 191 Choctaw County, Oklahoma __ ____ ___ __ ____ __ 26, 27 Choffat, P. __________________186, 189, 193, 198, 213 Christiansen, F. ------------------------------68 Chudeau, R. ----------------------------------196 University of Texas Bulletin Cia. Perforadora Mexicana -------------------180 Cinula washitaensis n. sp.______________.:._14s, 168 Cinulia sp. ------------------------------------54 Cleburne, Texas -------------------------------25 Coahuila, Mexico -------------------------179, 183 Cobb Brickyards, Fort Worth____ __ __ ___ ___ _____ 47 Codiopsis sp. aff. doma_______________ __________ 44 Coke County, Texas --------------------------25 Colorado formation __________________185, 200, 205 Comanchean sea in Texas_____________________ 44 Comanche Peak, Texas _____________________17, 24 Comanche series, thickness --------------------15 Comptonia wintoni n. sp. __________________ 97, 162 Constantine, provence of______________________ 65 Cooke County, Texas______________9, 12, 20, 22, 27 thickness of formations_____________ _______ __ 15 Coquand, II. -----------------------------194, 228 Corbula --------------------------------29, 31, 32 basiniformis n. sp. ---------------------130, 166 littorali.~ n. sp ________ ___ _______ ___29, 133, 166 Correlation of formations__________ ________ ____ 10 Cotteau, G. ------------------------__________146 Cradn, F. W. -----------------------------46, 146 Cretaceous, Mexican --------------------------231 Crustacea, tabulation of pyrite and Iimonite____ fl2 Cuesta de IIuanambra, Peru__________________199 Cuesta de IIuanyanba________ ____ ____ _________l ~9 Cummins, W. F., and Dumble, E. T.____________ 18 C11Phosoma volanum Cragin_______ ____________ _to.~ Cyprimeria washitaensi.~ n. sp. ___ _________134, 166 Dagger, explanation of ------------------------45 ~akota flora, age of --------------------------44 D:~:.rgJ~hn--==================================1:: Deba IIabe, India ----------------------------231 Decatur, Texas -------------------------------14 Del Rio, Texas ----------------------~-----58, 59 Del Rio clay______________l7, 18, 19, 41, 53, 56, 59 fauna of -----------------------------------58 limonite and pyrite fauna___________ ________ 61 Denison, Texas__ l7, 19, 20, 22, 24, 30, 47, 54, 55, 68 Denton County, Texas______9, 12, 17, 30, 35, 37, 54 thickness of formations__________ ________ ____ 15 Denton clay, fauna oL__________________55, 60, 62 Iimonite and pyrite fauna oL_____43, 61, 62, 63 marl ------------------------41, 46, 53, 54, 62 Descriptions of species________________68, et. seq. Desert sandstone ------------------------_____198 Desmoceras brazoense -------------------------23 Diego-Suarez ---------__ --------------________203 Diener, C. ------------------------------------197 Dieulefit, France -----------------------------65 Douvilleiceras mammilare ----------------------43 Duck Creek marL ____________ _______42, 53, 54, 62 fauna of --------------------------------54, 60 Iimonite and pyrite fauna oL__ __ __43, 61, 62, 63 upper and lower facies_____ ___ ___ ___________ 22 Dumble, E. T. -------------------------------146 and Cummins, W. F. -----------------------18 Durant, Oklahoma ----------------------17, 28, 29 Eag)eford shales __ _______________ ______ ___ 43, 199 Echinodermata -------------------------------232 tabulation of Iimonite ----------------------61 Echinoidea -----------------------------------101 Echinoid fauna of Washita formation__ ________ 52 of Weno formation _______ ___ _____ ___ __ _44, 52 Eck, 0. ________________________180, 195, 197, 227 Edwards formation ---------------------------24 facies --------------------------------------24 Egypt -------------------------------214, 218, 227 ammonites from ----------------------------180 fauna of -----------------------------------195 Salmurian of ___________________________193, 196 Turonian of ___________ _______ ___ ______188, 190 Ellenburger limestone ____ _____ __ ________13, 14, 16 EI Paso, Texas -----------------------------21, 24 Emscherian, the ____ l90, 196, 200, 205, 225, 226, 228 Enallaster _-------_--_--------__ ----__________lll bravoensis Boese ________________l 7, 41, 114, 164 sp. aff. texanus (Roemer) ________________31, 114 wenoensis n. sp. _______________________112, 158 Engonoceras ---------------------------26, 31, 32 serpentinum (Cragin) ------------------84, 156 sp. ---------------------------------54, 85, 156 Epiaster --------------------------------------34 Aguilerae Boese ______ _________________ 109, 158 subobesus n. sp. ------------------------110, 170 wenoensis n. sp. -----------------------105, 160 Escalon, Mexico ------------------------------183 Etheridge, R., Jr. -----------------------------198 Europe, Iimonite and prite fauna of_ _________ 64 Exogyra arietina_________________l8, 19, 31, 41, 42 cartledgei -----------------------------------18 cfr. olisiponensis Sharpe______________ ___l92, 230 columba Lamarck ----------------------199, 236 columbella Meek ----------------------------230 costata -------------------------------------231 Haarmanni n. sp. ------------------185, 230, 248 olisiponensis -------------------------------231 sp. aff. arietina Roemer _____________________123 texana -------------------------------------16 lVhitneyi ----------------------------17, 42, 231 Exposures of Pawpaw_________________________ 47 Facies' ----------------------------------------15 Fagesia -----------------------------196, 200, 211 Boucheroni Coquand ___ _________________ ____ _197 Haarmanni n. sp. _________________187, 211, 240 ](otoi ---------------------------------------198 rudra Stoliczka ____________________187. 198, 213 superstes ~ossmat__________l86, 187, 197, 198, 212 tevesthensM Peron________l86, 187, 188, 197 212 Fallot, J. E. -------------------------------~-65 Felix and Lenk______________________________ 25 Fink, Texas ----------------------15, 23. 24, 54 Finlay Mountains, Texas __________________16, 25 Flickia --------------------------------____26, 42 boesei. n. sp. ___________________________85, 150 bosquensis n. sp. ____ __ _________________ 87, 150 Fort Stockton, Texas _____________________16, 24 Fort Worth, Texas ------------------------­-----_12, 13, 14, 17, 20, 21, 24, 32, 47, 51 Fort Worth formation______________________2l, 22 facies of -----------------------------------22 geosyncline ---------------------------------13 limestone ----------------------------____22, 62 Fossil-bearing beds of Cerro de! Macho________l83 Fossils, pyrite ________________9, 33, 42, 44, 53, 60 Fourteau, R. ---------------------------------231 France, Salmurian fauna of_ __________________200 Turonian of --------------------------212, 223 Fredericksburg division ----------------------24 facies -----------------------------------· __ 24 thickness of --------------------------------15 Fritsch, A. --------------------------196, 197, 208 Gabb, W. F. ----------------------------------25 Gainesville, Texas, 12, 17, 19, 20, 25, 31. 32, 47, 51, 54 Gainesville Brick Company__________ 3l, 36. 47, 51 Gastropoda _________________________137, 191, 232 Gastropods, tabulation of pyritic or Iimonitic__ 63 Gatesville, Texas ------------------------------14 Geinitz, II. Br. ____________ ____ _______________202 Georgetown, Texas ________________________12, 14 limestone _____________________19, 20, 21, 41, 59 Geosyncline, Fort Worth formation____________ 13 Gervilliopsis invaginata -----------------------34 (White) -----------------------------------122 Ginger shale ---------------------------------36 Glenrose formation ------------------------14, 43 Globiconcha sp. --------------------------140, 168 Gondla, Nigeria _____ ----_________ ___ _________ 231 GoniOpygus sp. -------------------------------102 Goodland, top of -----------------------------24 fauna of -----------------------------------62 A New Ammonite Fauna of the Lower Turonian of Mexico 255 Grayson County, Texas _____________________ 9, 27 thickness of formation in___________________ 15 Grayson formation ______________17, 19, 29, 41, 53 facies of -----------------------------------17 fauna of -------------------------43, 56, 60, 63 limonite and pyrite faunae of__________6l, 62, 63 Graywacke -----------------------------------14 Gryphea ------------.-----------------------29, 35 Lamellibranchia ------------------------__ 191mucronata ------------------------------18, 19 tamellibranchiata ----------------------=--===227 dilatata ------------------------------------20 wa.shitaensis ----------------------21, 28, 29, 41 t!~~t, :L~-====================================2~~ Grossouvre, A. ---------------------------146, 223 Lau ~· G. C. ---------------------------197, 207Guillemain, C. --------------------------------196 emo1ne, P. -------------------------67, 180, 202 Lean?er, :rexas --------------------------------14Haarmann, E. ------------------180, 183, 184, !-'e~s1.ng,. m Comanchean formations ----------14 190, 191, 192, 205, 208, 211, 217, 218, 229, 230 ueiocidari~ ----------------------------____29, 101 L~on Sprmgs, Texas --------------------------14 Hacienda del Mohovano____________________l 79, 183 Hamites --------------------------------23, 26, 28 L~ddle•. R. A. --------------------------------59 quadrinodosus Jimbo ------------------------71 Lu~o~te and pyrite fauna of Africa__________ 65 simplex ----------------------------------42, 69 sp. -----------------------------------------54 sp. afl'. armatus Sowerby_____________________ 69 ~~ i:~:as~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~i-i~ tenawa Adkins and Winton-------------------69 L.summary of -----------------------------60-67 ~sson, .C· I. ----------------------------199, 200 Hamulina worthensis n. sp. ________________71, 152 Harbort, E. ---------------------------------196 Haslet, Texas ______________________ 21, 33, 51, 55 t1tholog1cal changes --------------------------16 oew, Oscar ---------------------------------208Haug, E. --------------------------------64, 146 Love ~ounty, Oklahoma -----------------------27Heinzia --------------------------------------201 Lunatu.i sp. --------------------------54, 140, 168 Helicocryptus mexicanus ---------------------41 McLennan County, Texas __________19, 35, 54, 56 Boese --------------------------------------139 Mada~~scar ~---------------------------~202, 203 Hemiaster ------------------------------180, 232 pynt1c fossils of ------------------67 Calvini Clark_______________l7, 42, 114, 158, 191 Mainst~eet limestone ___ _____________43,--47~-54-59 Fourneli -------------------_----------_---_228 Meslei Pe.ron e.t Gauthier____________________234 sp. ------------------------------------111, 252 riovistae n. sp. -----------------------115, 160 ' Hill County, Texas -----------------------20, 35 J~Ei~~::~~~~~~~~~~~~~~~~=~~:~~~~~~iii~'.Jl thickness of formation___________ ___________ 15 cfr..c;assitesta Stoliczka --------------197, 198 Hill, R. T. ------------~---------------15, 45, 146 concuiatus ---------------------197 198Hillsboro, Texas -----------------------------13 Hola.ster sp. afl'. simplex Shumard____________l04 Frif:sch ---------------------========---~-208 Stohczka -----------------------186, 207 208 subglobosus -------------------------------~ 43 Footeanus Stoliczka ______________________'__197 Holectypus limitis ------------------------33, 103 Laube et Bruder, emend. Petrascheck ______106 llo'Ynar'U9 ------------------------------------62 Mohovanen.~is n. sp. ________ __186, 206 220 236 Hood County, Texas --------------------------17 nodosoides Schlotheim__l86, 197 198 199 207 208Hoplitoides _____________________189, 196, 225, 231 var. Afra Pervinquiere ----·----~----·---' 199 afl'. mirabilis Pervinquiere --------------115, 250 Man.telliceras ----------------------___ -----===201ingens v. Koenen ---------------------------199 Mariscal Mountains, Texas ----------------18, 41 mirabilis Pervinquiere __________________190, 226 Mar~hall County, Oklahoma ------------------27Munieri -------------------------------190, 227 thickness of formations___________________ 15 nigeriensis ---------------------------------_227 ~edina _County, Texas _____________________58~ 59 sp. ----------------------------------------226 eleagrina -----------------------------------228Hoploparia -----------------------------------62 Metoecocera.s -------------------191, 200 201 202Horizons, fossil ------------------------------12 afl'..Whitei Hyatt ________________185: 101: 236 Hugo, Oklahoma ------------------------19, 24, 29 Geslianum Petrascheck _____________________185 Huronian slates ------------------------------14 sp. nov: ----------------------185, 192, 105, 235Hyatt, A. -------------------------------201, 202 India, fauna of __________________198, 200, 209, 212 ~;,~:r-===============================ig:: ~~~ :et'?paster hortensae Adkins and Winton____97, 162 Inoceramus Sowerby -----·--------------------229 hercynicus Petrascheck ________________ 179, 191 labiatus Schlotheim ----------------------­ ______________ l 79, 186, 190, 192, 200, 129, 252 ~~~~~~~~~~~~~~~;;;;;;;;~~;;~~;;~~;;~;;;~;:ii . cycloides -----------------------------------191 Instituto Geologico de Mexico_____ _____________229 ~O:t1.~n~~--==============================~1, 1:~ Mungo region, of Africa _________________19(;~-225 Jack R. L. ----------------------------------198 Myra, Texas ---------------------------------13 Japan, Turonian fauna of_____________________l98 Johnson County, Texas _________9, 20, 35, 51, 54 Nacreous fossils, Weno _________________26, 44, 54 thickness of formations in ------------------15 Johnston, A. W. -------~---------------------14 Juarez, Mexico --------------------------191, 192 ~~;r!;t;~~~~~~~~~~~~~~~~~·;;~;~~;~~~~~~~~~:~.~1li Kamerun, Africa ________________________189, 225 !Veoptychites ------------------------196, 200 221 fauna of ----------------------------------19p afl'. cephalotus Courtiller __________189, 11/ 248 Kanab Valley, Utah --------------------------20~ af!'. xetriformis Pervinquiere____l 79, Ill, 226', 248 Kent, Texas -·--------------------'---16, 18, 25, 35 Kiamitia formation _________ _______23, 40, 53, 54 cr~ssu.~ Solger ------------------------------189 telingaeformis Solger -----------------------189conglomerate -------------------------------24 University of Texas Bulletin 'l'el-inya. Stoliczka __________________ 189, 198, 223 xetra ________ _: ____________ ----------·-------224 · xetriformis ________________________189, 222, 224 N erinea sp. ----------------------------------54 N erita sp. -------------------------------189, 168 Neritina sp. ______ _____ _____ __ _____ ______189, 168 Nigeria, fauna of__________l96, 209, 214, 227, 231 Nodo.,aria texana ____ 18, 19, 28, 32, 34, 41, 145, 170 Noetling, F. -----------------------------146, 197 Noland's River --------------------------------33 North Central Texas ------·-------------------40 North Denison sands -------------------------45 Northern Europe, fauna of ___________________ 197 France fauna of ___________________________ 197 Germa~y, fauna of _________________________197 Tunis pyritic fauna of ---------------------66 Nucula ' ________________________________ 29, 31, 32 nokonis n. sp. -------------------------118, 168 wenoensis n. sp. ________________________ 120, 168 Oklahoma ------------------------------------40 Opal, Zacatecas __________________________60, 191 O.