Publications of The University of Texas PUBLICATIONS COMMITTEE E. J. MATHEWS J. T. PATTERSON D. CONEY A. SCHAFFER B. M. HENDRIX B. SMITH A. C. WRIGHT General Publications J. T. PATTERSON R.H. GRIFFITH LOUISE BAREKMAN A. SCHAFFER FREDERIC DUNCALF G. W. STUMBERG FREDERICK EBY A. P. WINSTON Administrative Publications E. J. MATHEWS L. L. CLICK C. F. ARROWOOD C. D. SIMMONS E. C. H. BANTEL B. SMITH The University publishes bulletins four times a month, so numbered that the first two digits of the number show the year of issue and the last two the position in the yearly series. (For example, No. 3801 is the first publication of the year 1938.) These bulletins comprise the official pub­lications of the University, publications on humanistic and scientific subjects, and bulletins issued from time to time by various divisions of the University. The foIIowing bureaus and divisions distribute publications issued by them; communications concerning publications in these fields should be addressed to The University of Texas, Austin, Texas, care of the bureau or division issuing the publication: Bureau of Business Research, Bureau of Economic Geology, Bureau of Engineering Research, Bureau of Industrial Chemistry, Bureau of Public School Extracurricular Activities, and Division of Extension. Communications concerning all other publications of the University should be addressed to University Publica­tions, The University of Texas, Austin. Additional copies of this publication may be procured from the Bureau of Economic Geology, The University of Texas, Austin, Texas at $1.50 per copy THE UNIVERSITY OF TEXAS PRESS ~ No. 3801: January 1, 1938 STRATIGRAPHIC AND P ALEONTOLOGIC STUDIES OF THE PENNSYLVANIAN AND PERMIAN ROCKS IN NORTH-CENTRAL TEXAS By WALLACE LEE, C. 0. NICKELL, JAMES S. WILLIAMS, AND LLOYD G. HENBEST Bureau of Economic Geology E. H. Sellards, Director PUBLISHED BY THE UNIVERSITY FOUR TIMES A MONTH AND ENTERED AS SECOND·CLASS MATTER AT THE POST OFFICE AT AUSTIN, TEXAS, UNDER THE ACT OF AUGUST 24, 1912 The benefits of education and of useful knowledge, generally diffused through a community, are essential to the preservation of a free govern· ment. Sam Houston Cultivated mind is the guardian genius of Democracy, and while guided and controlled by virtue, the noblest attribute of man. It is the only dictator that freemen acknowledge, and the only security which freemen desire. Mirabeau B. Lamar CONTENTS PAGE STRATIGRAPHY OF THE CISCO GROCP OF THE BRAZOS BASIN, by \\·allace Lee________________________________________________________ __________ ·-----------------------------11 Introduction -------------------------___ _ __________ _ 11 Pennsyh-anian system ___ _____________________ _ 11 Cisco group restricted _________ __ ______ 11 Graham formation ------------------------------------------------------------------------------------12 Divisions ---------------------------------------------------------------------------------------------12 Base of the Graham formation (Kisinger channel) __ __ ____ ___________ 12 Salem School limestone member __________ ____ -----------------------------------16 Salem School limestone member to Gonzales limestone member 16 Gonzales limestone member______________________ --------------------------------------18 Gonzales limestone member to Bunger limestone member __ ___ ____ 19 Bunger limestone member_________________________ -----------------------------------22 Channel below the Bunger limestone member______ 24 Bunger limestone member to top of Wayland shale member__ __ 2-i No. 1 post-Bunger cycle _ ---------------------------------------------_ 26 "\'o. 2 post-Bunger cycle ________________________ -------------------------28 No. 3 post-Bunger cycle __ __ _____ ______ _ 31 No. 4 post-Bunger cycle ___ _ ----------------------32 No. 5 post-Bunger cycle __ ------------------------------------33 No. 6 post-Bungt>r cyrle 34 .:\'o. 7 post-Bunger cycle ___ 37 No. 8 post-Bunger cycle ------------------------------------39 No. 9 post-Bunger cycle_ 43 Channel depMits ___ _ 43 WaYland shale member -------------------------45 Gunsight limeston e memb er__ __ _ __ 53 Thrifty forrnati\ln _ 54 Harpers\·illc formation -------------------------61 Pueblo format ion ---------··· --------------------------74 Permian system __ 79 \\-ichita group rt>d efi ned (]Ja::-al part) _ 79 .\Ioran formation 79 Putnam formation 82 Summary of formations __ _ ___ ------------------------------------------84 Depositional cycles 85 Geologic history _____________________ ----------------------------------------------------------------86 Economic application of results _____ --------------------------------------------------------88 STRATIGRAPHY OF THE CA:\YO'.\' A'.\'D CISCO GROl!PS ON COLO­RADO RIYER I:\ BRO\C\' A'.\D COLE.\IA~ COl1'.\'TIES,-TEXAS, by C. 0. Nickell ------------------------------------------------------------------------------------------------91 Pennsyh·anian system --·------··-·--------·---·----------------------------·-·----------------------------91 4 The University of Texas Publication No. 3801 PAGE Strawn group ---------------------------------------------------------------------------------------------------91 Mineral Wells formation__ ----------------------------------------------------------------------91 Canyon group --------------------------------------------------------------------------------------------------94 Palo Pinto formation____________________________________________________________________________ 95 Graford formation redefined -------------------------------------------------------------------96 Lower part of the Graford formation ---------------------------------------------100 Upper part of the Graford formation------------------------------------------103 Brad and Caddo Creek formations.___________________________ _____________________ _ 108 Readjustment of boundary lines__________________________________________________ 108 Brad formation redefined_________________________________ ____________________________ 111 Caddo Creek formation-------------------------------------------------------------------------115 Cisco group (restricted) -------------------------------------------------------------------------------118 Graham formation ------------------------------------------------------------------------------118 Thrifty formation ----------------------------------------------------------------------------------122. Harpersville formation ------------------------------------------------------------------------128 Pueblo formation -------------------------------------------------------------------------------------132 Permian system --------------------------------------------------------------------------------------------------134 Wichita group redefined_________________________________________________________________________________ 134 Moran formation ------------------------·-----------------------------·---------------------------134 Putnam formation ------------------------------------------------------------------------------------137 Summary --------------------------------------------· -----------------------------------------------------------------138 COMPARISON OF BRAZOS AND COLORADO RIVER SECTIONS, hy Wallace Lee -------------------------------------------------------------------------------------------------139 CARBONIFEROUS INVERTEBRATE FOSSILS (EXCEPT FUSULIN­IDS) FROM NORTH-CENTRAL TEXAS, by James Steele Williams____ 149 Introduction ----------------------------------------------------------------------------------------------------------149 Outline of report ________________________ -----------------------------------------------------------------------150 Localities of individual collections______________________________________________________________________ 152 Date of identifications_________ __ _______________________________________________________________________________ 152 Collections from the Graford formation ____________________________________________________________ 152 Collection from the Brad formation ____________________________________________________________________ 154 Collections from the Caddo Creek formation ----------------------------------------------------156 Collections from the Graham formation _______________________________________ _____________________ 159 Brazos River valley______________________________________________________________________________________ 160 Colorado River valley_________________________________________ ____________________________________________ 183 Correlation of members of the Graham formation _____________________________________ ·188 Age and outside correlation of the Graham formation _______________________________ 193 Collections from the Thrifty formation _______________________________________________________________ 194 Brazos River valley______________________________________________________________________________________ 194 Colorado River Valley____________________________________________________________________________________ 198 Correlation of members of the Thrifty formation______________________________________ 200 Fauna] means of differentiating the Thrifty from adjacent formations_ 201 Outside correlation of the Thrifty formation ______________________________________________ 201 p _.\ GE Collections from the Harpersville formation ______________________________ ____ _ _ _______ __ 202 Brazos River valley_ _______________________ ___________ __ ________ _______ ____________ __ ______________ 202 Colorado River valley_ _ _ ____________ __ __ _________ _ _ ______ __ __ ___________________________________ 208 Correlation of members of the Harpersville formation_ _ _______ __ __ _ __ _ _ ______ 210 Fauna! data for di5tinguishing the Harpersville from adjacent forma­ti ons __ _________ __ -----------------------------------------------------------------------------_ _____ ____ 211 Outside correlation of the HarpersYille formation ___ ________ ______________ 212 Collections from the Pueblo formation _ __ ____ _ ___ __ ----------------------------------------------212 Brazos River rnll ey______ _____________________ _________________________________________________ _ ____ 213 Colorado River valley________________________ _ _ ____ _ ________ _______________ __ _____ ________________ 213 Correlation of members of the Pueblo formation __ ______ ___________ _ ______ _ _ __ 215 Outside correlation of the Pueblo formation--------------------------------------------215 Collections from the :\Ioran formation____ __________________ _ ______ _______________ _________ __ __ 215 Colorado River Yal ley __ __________ _ ------------------------------------------------------------------216 Correlation of the :\loran formation _ -------------------------------------------------------218 Collections from the Putnam formation____________________ __ __ ____ _ ____ _______ __ ___ _________ _ 218 Correlati on of the Putnarn format ion______ _______ ___ _____________ _ _________ ______________ 219 Register of localities---------------------------------------------------------------------------------------------226 NOTES O~ THE RA~GES OF FCSULINIDAE I~ THE CISCO GROUP (RESTRICTED 1 OF THE BRAZOS RIYER REGION, NORTH­CE\FTRAL TEXAS, by Lloyd G. Henbest___ _______ __ _________________________________ _ 237 Int rod uction _______ __ __ ________ __ __ -----------------------------------------------------------------------------------237 Noles on species __ ______ ___ _______ --------------------------------------------------------------------238 Identification of fusulinid faunas by external features ------------------------------------243 Regi,,:ter of local it its_ ____________ -------------------- __-------------------------__________ __ _ 2-i4 ILLUSTRATIONS fIGCRJ::S PAGE 1. Key map of north-central Texas showing areas studied____________ 8 2. Diagrammatic cross section of Caddo Creek formation and lower part of Graham formation, southeastern Young County, Texas_____________ 23 3. Diagrammatic cross section through Rocky l\found _________________________________ 43 4. Generalized cross sec tion of the Harpersville formation from outcrops between Crystal Falls, Stephens County, and :'.\IcCann Bridge, Young County, Texas.... _ --------------------------------------------------------------------62 5. Sketch showing details of Crystal Falls limestone member in railroad cut, Crystal Falls, Stephens County, Texas_____ __ _ __________________________ 64 6. Compari son of measured sections of lower part of Graford formation (redefined I and upper part of Strawn group in Brown County, Texas -----------------------------------------------------------------------------------------------------93 7. Comparison of sections of the Winchell member of the Graford forma­ tion (redefined 1 measured near Winchell, Brown County, Texas_ 106 6 The University of Texas Publication No. 3801 PAGE 8. Columnar sections showing different usages of names for subdivisions of Brad, Caddo Creek, and Graham formations, Brown County, Texas -------------------------------------------------------------------------------------------------------110 9. Sketch showing the relation of areas studied to certain structural features of the region___________________________________________________________________________ 145 Pl.ATES (IN POCKET) I. Map of southeastern Young County, Texas, showing outcrops, cross section, and subsurface extension of the Kisinger channel at base of the Cisco group. IL Generalized cross sections in southern Young County and northern Stephens County, Texas, showing post-Bunger unconformities of the upper part of the Graham formation revealed in surface exposures. III. Generalized cross section showing unconformities of the Tiuifty for­ mation as revealed in outcrops in southern Young and northern Stephens counties, Texas. IV. Columnar section of lower part of Wichita group (Moran and Put­ nam formations) and Cisco group restricted in Brazos Basin. V. Map showing outcrops of prominent beds of lower part of Cisco group, southern Young and northern Stephens counties, Texas. VI. Map showing outcrops of prominent beds of upper part of Cisco group and lower part of Wichita group, southwestern Young, southeastern Throckmorton, and northwestern Stephens counties, Texas. VII. Columnar sections showing relations of Graford, Brad, Caddo Creek, and Graham formations, Brown County, Texas. VIII. Columnirr sections of upper part of Strawn group, Canyon and Cisco groups, and lower part of Wichita group adjacent to Colorado River in southern Coleman and Brown counties, Texas. IX. Map showing outcrops of principal members of the canyon and Cisco groups and lower part of Wichita group redefined north of Colorado River in southern Brown and Coleman counties, Texas. X. Graphic correlation of columnar sections of lower Permian and upper Pennsylvanian formations of Colorado River and Brazos River areas. lX. Chart showing distribution of Fusulinidae in the Cisco group (re~ stricted) of the Brazos River region, Texas, and in the Missouri group of Nebraska and Kansas___________________________________Facing page 238 PREFACE The investigations in north-central Texas the results of which are recorded in this report were carried on by the United States Geological Survey with funds allocated to the Survey under the Public Works Administration. The project included stratigraphic studies in Brown and Coleman counties on the Canyon and Cisco (restricted) groups of the Pennsylvanian by Clarence 0. Nickell assisted by Fred F. Y ockstick; stratigraphic studies of the Cisco group (restricted) in Young, Stephens, and Throckmorton counties by Wallace Lee assisted by Ivan J. Fenn; subsurface studies of the Bunger and associated oil pools in southeastern Young County, by Lloyd E. Wells, and of the Cross Cut-Blake oil pools in north­western Brown County by Edgar D. Klinger assisted by R. B. Cheney. The results of the subsurface work on the Bunger and Cross Cut-Blake districts to which occasional reference is made in this report are to be published elsewhere. The areas in which the stratigraphic work was done are shown on the accompanying guide map (fig. 1). Fossil collections in the areas of field work were made by James Steele Williams whose report on the invertebrate fossils except fusulinids is included in the report. Lloyd G. Henbest has reported on the fusulinids collected by the field parties. Both the pale­ontologic reports added materially to the results of the field work. Pennsylvanian system, Permian system, Cisco group restricted, and Wichita group redefined, as herein used, correspond to the Pennsylvanian series, Permian series, Cisco group, and Wichita group as now accepted by the United States Geological Survey. This usage has been followed to accord with the present classifica­tion of the Texas Bureau of Economic Geology. The Permian­Pennsylvanian boundary in this region is, however, still a debated subject. The writers of these reports are greatly indebted to many firms and individuals who gave freely of their facilities and information, and without whose aid only a part of the work could have been accomplished in the time available. Among the firms who helped materially by supplying maps, logs, and altitudes are The Conti­nental Oil Company, The Texas Company, Atlantic Oil Company, The University of Texas Publication No. 3801 Shell Petroleum Corporation, Stanolind Oil Company, Sinclair­Prairie Oil Company, Humble Oil & Refining Company, Gulf Oil Corporation, Laughlin & Simmons, Hudnall & Pirtle, Hightower Oil & Refining Company, Carter Oil Company, and Mid-Continent Oil & Gas Company. LEGEND AREAS STUDIED ~ Fig. 1. Key map of north-central Texas showing areas studied. Preface Among the many indiYiduals to whom the geologists contributing to this report are indebted are R. T. Hill, Dallas, Texas; M. G. Cheney. Coleman, Texas; Ben H. Ramsey, Graham, Texas: T. F. Petty and John F. BrickeL Cisco, Texas; W. D. Kelley, J. J. Maucini, Ralph S. Powell, Virgil Pettigrew, Everett C. Parker, Frank Parsons, John A. Kay, and \I. l\1. Garrett, Wichita Falls. Texas; R. E. GraYes and C. D. Anderson, Brmrnwood, Texas; H. B. Fuqua, J. B. LoYej oy, H. S. Clark, and J. M. Armstrong. Fort \Vorth, Texas; and A. L. Beekley and A. F. Truex, Tulsa, Oklahoma. :\Iany others assisted from time to time and no one from "-horn information or help was asked failed to cooperate. The Yarious projects were undertaken after consultation "·ith the director of the Texas Bureau of Economic Geology and the officers of the .\orth Texas Geological Society, the Fort \Vorth Geological Society, and others interested in the economic deYelopment of north­central Texas. \Vork was commenced on April 2. 193-l-, an.d the field work "·ns completed by the seYeral parties at Yarious dates in September, 193 L The manuscripts of the yarious reports 1rere completed in the fall of 1935. The stratigraphic work laid special emphasis on the details of the sections 'rith a Yiew not only to determine the interrnls bet\reen key beds useful in the determination of structure for the deYdop­ment of oil and gas, but also to determine the Yari<:;tions that occur in the character and thickness of the beds in different areas. Considerable information was procured in regard to unconformi­ties \rithin Yarious formations which should be useful in oil deYelopment. During the editing of the rnrious papers included in this report, it became necessar~-to abandon the term ::\Ierriman limestone 1!1em­ber originally applied to a specific bed in the Ranger district ·which has subsequent! y been rather loosely used. A new and more inclusiYe term, the \\"inchell member, has been introduced for the reasons explained in the paper on the "Stratigraphy of the Canyon and Cisco Groups on Colorado RiYer in Brown and Coleman Counties." The term \"Vinchell member has been inserted also in the other parts of this report although the older term was used by the seYeral authors in the original manuscripts. WALLACE LEE. August 15, 1935. STRATIGRAPHY OF THE CISCO GROUP OF THE BRAZOS BASIN WALLACE LEE INTRODUCTION The study of the stratigraphy of the Cisco group along the Brazos RiYer was begun on April 2 and completed on September 30, 1934. Much 'rork had already been done on the stratigraphy of the region as a whole, Lut no local study of so detailed a character has hereto­fore Leen made. Earlier work had been concentrated on the lime­stones of the section as the most direct approach to the study of the structure of the area for oil development, and the sandstones and conglomerates of the section had received less attention than their importance has now been found to justify. The relation of the discontinuous limestone beds to the sandstones and to the many unconformities had not previously been recognized. A number of facts of considerable significance for working out the structure and also concerning the character of the sand bodies in which oil accumulation takes place down the dip have been learned. On account of the numerous unconformities the work proved difficult and slow, and the determination of the complicated relations of the various outcrops to one another resembled in many respects the solving of a jigsaw puzzle. For this reason the description of the different formations and their thin and interrupted component members is necessarily detailed. The areal geology is shown in Plates V and VI. PE.\NSYLVAl\'IAl\ SYSTEM CISCO GROUP RESTRICTED The Graham, Thrifty, Harpersville, and Pueblo formations con­stitute the Cisco group, the highest division of the Pennsylvanian, as here limited. Formerly the Moran and Putnam formations were also included in the Pennsylvanian, but the Texas Bureau of Issued Julv, 1938. Economic Geology1 now places these formations in the Permian, thus restricting the earlier definition of the Cisco group. The formations of the Cisco group are composed chiefly of shale, sandy shale, and sandstone, with a considerable number of thin limestone beds, many of which are discontinuous. The formations, particularly in the area along Brazos River, contain a great many unconformities, and those in the lower forma­tions of the group are particularly conspicuous. GRAHAM FORMATION DIVISIONS The Graham formation, not including the filled channel at its base, is at least 590 feet thick, the uncertainty being due to the fact that the formation is bounded both at the top and bottom by unconformities. In the Brazos River region it is conveniently divided into the following unitsi for discussion: Thickness Feet Wayland shale member --------------------------------------------------------------------------110 Shale, with numerous channels and unconformities ________________ _______ 174 ~h~l~era~~m:!~0ds~o:e_~-~~~~~~:=::::=--~~::::::::::=::::::::::::::::=::::::::::::=::::::::::::: 16~ Gonzales limestone member___________________ _______________________________________________ __ 18 Shale and sandstone____________________ ____________________________________________________________ 113 Salem School limestone member__________________________________________________________ 1 Channel deposit ---------------------------------------------------------------------------------------­ 590 To this must he added a thickness of at least 150 feet for the channel deposit below the Salem School limestone. As the forma­tion is bounded both above and below by unconformities, no definite thickness for it can he set. Measurable and convenient limits for a partial thickness of the formation, however, are from the base of the Salem School limestone member up to a limestone bed at the base of the \Vayland shale member, an interval of 480 feet. BASE OF THE GRAHAM FORMATION (KISINGER CHANNEL) The lowest division of the Cisco group is the Graham formation. At its very base an unconformity is manifested in a deep channel in the southeast corner of Young County, on the southern margin 1Scllards, E. H., Adkins, W. S., and Plummer, F. B., The Geology of Texas, Vol. I, Stratigraphy: Univ. Texas Bull. 3232, pp. 140-144, 1932 [1933]. of which is the Kisinger oil pool. This channel (Pl. I) was e1'Dded through the Home Creek limestone member at the top of the Caddo Creek formation and an undetermined amount into but not through the Ranger limestone member at the top of the under­1~ ing Brad formation. The following composite section shows the sequence of beds immediately below the Graham formation. It "-as measured on the southern margin of the channel, where it is belieYed that not much erosion has taken place, though there is no way of determining locally how much of the Home Creek limestone mav have been removed. Thickne3s Feet Horne Creek lime,otone member_ 38+ ~hale 2 :-·and,-tone (lenticular and Yariable I __ _ 2-18 Talus (probably shale I Ranger limestone member (ba~.e not exposed I_ _107-91 is+ This report is not concerned "-ith strata below the Cisco group, but it is \rnrth mentioning that the sandstone below the Horne Creek difTers so much in thickness from place to place that the presence of an unconformity \\ ithin the Caddo Creek formation is suggeqed. This sandstone is 2 feet below the base of the Home Creek on the bluff southeast of the mouth of Connor Creek. \\here it is 2 fret thick, but 2 miles distant on the bluff half a mile north­east of :\ling Bend School, it is 18 feet thick. ::\o extensfre studv of this sandstone, ho,rever, was made. As the channel at the base of the Graham formation has been cut completely through the Caddo Creek formation and into the Ranger limestone, it was at least 1-19 feet deep and probably not less than l GO feet deep. The channel \ms therefore commensurate in depth with the present rnlley of Brazos River, though in this locality it did not attain the maturity of erosion of the present cycle. The lo\\-er part of the channel is filled \\-ith quartz sandstone and chert conglomerate. l\fost but not all of the pebbles are sub­angular and 1 inch or less in diameter, but a f e,\-3 inches or more in diameter \rere noted. The pebbles are very irregularly distributed in the sandstone, occurring in interrupted bands and masses with cross-bedded and swirling lines of deposition at all levels. They are chiefly gray and white chert, though there is a considerable variety of other pebbles, including black and banded chert and some green­ish material that may be novaculite, but there are no quartz pebbles. All the material, so far as known, could have been derived from a southwestward extension of the Ouachita Mountains, which were being raised at this time. Earlier studies of the Pennsylvanian con­glomerates of the Brazos Valley have indicated that the material came from this source.2 The greatest thickness of sandstone and conglomerate measured at any point is 55 feet, though the deposit is undoubtedly thicker. The upper part of the material filling the channel is sandy shale and laminated shaly sandstone containing quantities of macerated plant fragments. In many places the laminae are almost coaly, and at one point 2 inches of impure coal was seen. This sandy shale member is 22 to 30 feet thick near the margin, but toward the center of the channel in some places it is thicker. On the west side of Connor Creek about a mile above its junction with Brazos River, fossil leaves were collected from ferruginous shale concretions in channel deposits between the Salem School limestone member and the top of the conglomeratic sandstone. These specimens were ex­amined by Charles B. Read, of the United States Geological Survey, who reports the following species: Mariopteris sillimani (Brongniart) White Neuropteris ovata Hoffman Asterophyllites equisetiformis (Schlotheim) Brongniart Annularia stellata (&hlotheim) Wood Sphenophyllum sp. Dicrauophyllum sp. Cordaites sp. Sigillaria sp. As might be supposed, the sides of the channel vary considerably in the angle of slope. Where it is steep there is no difficulty in determining the contact of the channel deposit with the channel wall. Where, however, the slopes were low the trace of the old surface on the present topography is irregular and is not every­where easy to follow or map. At most places where erosion has exposed the contact of the channel deposits with the old surface, these deposits contain large and small boulders and pebbles of Home Creek limestone incor­porated in the contact conglomerate. In many places huge masses of 2 Bay, Harry, A study of certain Pennsylvanian conglomerates of Texas: Univ, Texas Rull. 3:l01, pp. 149-188, 1933. Stratigraphic and Paleontologic Studies Home Creek limestone dislodged from the ancient rim rock occur at Yarious leYels in the contact deposits, as shown ou the southeastern margin of the channel in the accompanying sketch (Pl. I). These pebbles and boulders do not differ in appearance from similar debris from the present outcrops of Home Creek limestone and suggest that the Home Creek limestone was already consolidated at the time of its first exposure and erosion. The sketch (Pl. I) shows the areal extension of the channel as indicated by the edge of the eroded Home Creek limestone in the outcrops. Lloyd E. \Veils, "-ho was ,..-orking on the subsurface of the Bunger oil pool, which lies immediately to the west, was able to trace certain areas in which the Home Creek limestone is absent in the well logs in that area. These are also shown in Plate I. It is eYident that as 38 or more feet of erosion must have taken place to remoYe the Home Creek limestone completely, only the deeper parts of the subsurface channel in general can be definitely recog­nized in this way, and the actual width of the channel in the sub­surface area is greater than that shown. Certain areas in the surface exposures where the Home Creek limestone was not entirely removeJ show limestone conglomerate at the top of the limestone, and some well logs show only partial sections of the Home Creek. Howen:>r, the accuracy of many of the well logs is questionable. In some logs the conglomeratic sandstone has either been logged as limestone or not mentioned at all, to the confusion of the subsurface investi­gation of the channel deposits. The deeper part of the channel along Connor Creek, where the Home Creek limestone is entirely removed on the outcrop, is about 2 miles "-ide toward the northeast and tapers soutlrn·estward to a width of less than l mile on Herron Bend. :\"o subsurface extension of the deep, broad channel of the surface outcrops could be detected in the logs, which, in the Bunger pool, suggest a branching tributary channel. The channel exposed at the surface tapers to,rnrd the southwest in this area and its course in consequence appears to hm·e been toward the northeast. As the source of the pebbles in the con­glomerate, howeYer, appears to haYe been to the northeast, it seems probable that the channel as here defined 'ms tributary to a basin somewhere to the east, where the Home Creek limestone is erratic in its distribution, and that the filling of the channel was coinci­dental with the filling of the basin. This channel deposit is here considered the basal deposit of the Graham formation; the Salem School limestone, which immediately overlies it, is therefore the first marine member of the Graham formation. SALEM SCHOOL LIMESTONE MEMBER The bed which is here named the Salem School limestone member of the Graham formation is a yellowish earthy limestone crowded with marine fossils. It is in few places more than 8 inches thick, but over the central part of the channel on Connor Creek it is nearly 2 feet thick. This bed is particularly interesting because it overlies both the channel deposits and the older Home Creek lime­stone. Half a mile southeast of Salem School, where it is well exposed, it is 5 feet above the Home Creek limestone. On the south side of the channel, a short distance south of Ming Bend School, it is 1 7 feet above the Home Creek. As the Horne Creek limestone was exposed to erosion prior to the deposition of the Salem School limestone, the variations in the interval between them may be attributed to erosion of the surface of the Home Creek limestone. However, near Salem School there is no evidence of unconformity, although during the interval represented by the 5 feet of shale separating these beds, a channel more than 150 feet deep was eroded and filled. The regional extension of the Salem School limestone is not now known, but it was recognized above the Home Creek north of Finis, at least 1 mile from the margin of the channel. Where the Home Creek limestone is absent this limestone has previously been mapped as Home Creek. This has probably not involved any serious error in the determination of structural relations, though there is reason to believe that there is a lowering of the Salem School limestone over the central part of the channel. Probably less error is in­volved in using this bed as a datum plane than in using the eroded surface of the Home Creek itself. SALEM SCHOOL LIMESTONE MEMBER TO GONZALES LIMESTONE MEMBER The interval from the top of the Salem School limestone, on the margin of the channel which it overrides, to the top of the Gonzales limestone was found at two places on the northwest side of the channel to be 130 feet and 134 feet. Over the channel no intervals so small as these were measured, the interval ranging from 140 to 148 feet. It appears likely that either through compacting or incom­plete filling of the channel, the Salem School is lower over the center of the channel than elsewhere. The following section is representative of the beds from the Salem School limestone to the Gonzales limestone: Section from Salem School limestone to Gonzales limestone half a mile south east oj Salem School, southeastern Young County. Thickness Feet 12. Gonzales limestone member, only partly exposed (estimated) 16 11. Not fully exposed, probably shale with some sandstone beds 36 10. Sandstone, massive -----------------------------------------------------__________________ _ 2 9. Not exposed, probably shale__________________ -----------------------------------------5 8. Sandstone _______ ______ __ ____ __ ______ _________ --------------------------------1 7. Shale, dark, weathering buff, with thin partings of yellow clay ironstone --------------------------------------------___________________________ 10 6. Sandstone _________________ -------------------------------------------------______ 2 5. Sandy shale, platy, with macerated plant fragments________________ 10 4. Shale, gray ____________ _____________ __ ___ _____________ _____ ____ ______ __________ ____ ____ 15 3. Shale, gray, clay ironstone concretions and many fossils, particularly gastropods, in lower 5 feeL____________ _ ________________ 17 2. Shale, black, fissile, nonfossiliferous; on weathering forms abundant gypsum crystals_____________ ________________________ 15 1. Salem School limestone member, hard, earthy; weathers yellowish; fossiliferous --------------------------­ 130 The black fissile shale (bed 2 of the section) is present both above the channel deposits and outside the channel area but is seldom reported in well logs. The abundant gypsum crystals of the exposures are a conspicuous and unique feature. The 56 feet of beds 6 to ] 1, immediately below the Gonzales limestone, contains bands of sandstone and many irregularities of sedimentation, but nothing suggesting channeling was seen. In the outcrops on Brushy Mound, a hill south of the Graham-Finis road and east of Connor Creek, a thin fossiliferous limestone appears about 45 feet below the top of the Gonzales limestone. This horizon lies within the interval of alternating sandstones in the above section, and the absence of the limestone near Salem School may be an indication of its erosion and replacement by a sandstone bed. This change would be quite in line with the usual sequence of events, but this bed is only a few inches thick and could not be followed, as its horizon is nearly everywhere covered by talus. GONZALES LIMESTONE MEMBER The Gonzales limestone is well exposed on a high, nearly inac­cessible westward-facing bluff on the south side of Brazos River opposite and southeast of Salem Bend, where it is 18 feet thick. This is the only place where a complete and unweathered section of the Gonzales limestone was seen. Section of Gonzales limestone member and associated beds on bluff oppo~ site Salem Bend, southeastern Young County. Thickness Feet Inches 5. Conglomeratic sandstone ----------­------­--------­------------------­--­-------­-4. Shale, gray, sandy_____ _______ ____ __ __ _____ __ ___ ___ ____------­---­--­--­----­-----­- 7 6 3. Sandstone, fine grained, dense, thick bedded, light gray; bedding irregular, in part limy________________________________________ 9 Unconformity 2. Gonzales limestone member (18 feet) : Limestone, hard, resistant, fossiliferous; top bed crowded with crinoid stems, weathers yellow to buff 4 Limestone beds alternating with thin shale partings containing fusulinids Limestone composed -----­---­-------------­--­---------------­-----------­-almost entirely of broken 2 brachiopods ---------­--------------­-------------­----­---------­----­------­- 3 Li~eston~ b~ds a~ternating with shale; shale beds mcreasmg m thickness -------------------­----------------------------­- 1 9 Shale, limy, very fossiliferous, crowded particularly with fusulinids, though fusulinids are common in all the shale partings----­----------­--­--­-----­--------­--­----­--------­-Limestone, irregularly bedded, nodular, dark gray, 2 not particularly fossiliferous-­----------­--­--------------­---------­- 3 Limestone, sandy, crowded with fusulinids ­-----------------­-­Limestone, sandy, or limy sandstone; no fossils_ ____________ 1 4 1. Sandstone with fucoidal webs_ _____ ____________ _________________________ 4 44 As the top of the Gonzales limestone is in contact with sandstone unconformably above it, the entire original section of the Gonzales may not be represented even here, though this section is thicker than any other in the area. Most of the limestone beds of the Gonzales are either very thin bedded or earthy or sandy. This con­dition reduces their resistance to weathering, so that few outcrops show the whole section, and the beds are commonly so much altered as to be difficult of recognition. Earthy limestones may alter to flaky masses: sandy limestones are leached to soft sandstone; and the thinner beds break dmrn and become coYered by the talus from the resistant sandstone beds aboYe. The beds are rarely seen except on well-drained areas high on hill slopes. In weathering by moist­ure the beds are so completely leached that they disintegrate. In some places only the upper parts of the section are \\-ell ex­posed, "·hereas in others only the basal beds are seen. In the saddle south of Brushy :\Iound the greater part of the topmost lime­stone is conspicuous in a bench. The lower beds, howeYer, "-hich contain Yery abundant fusulinids. are inconspicuous. being repre­sented only by small fragments in the talus. On the other hand, along the road from Graham to Henry"s ChapeL west of Connor Creek on a hillside north of the road, only a f e\\-weathered frag­ments of the upper members are recognizable in the talus about the outcrop. The basal limy sandstone member is conspicuous, but the member containing the fusulinids is seen in bet few places. ~\s this member is followed along the hillside to,rnrd the west it slopes to a lower altitude and the leaching becomes progressiYely more nearly complete. The bed passes first into blocks leached along the surface and bedding planes. Farther on the leaching attacks the joints, leaYing only a central kernel of unaltered sandy limestone. Finally all semblance to the original rock is lost, and the once limy sandstone with fusulinids becomes indistinguishable except by its porosity from the oYerlying blocks of sandstone in the talus. Contrary to appearances, the beds of the Gonzales do not change radically in character within short distances along the outcrop. It is the phases of \reathering which materially affect the appearance of different outcrops of the same bed from point to point. By a careful study of the characteristics and fossil content of the different beds it is possible to identify them with a consid­ erable degree of accuracy oYer considerable areas. GONZALES LIMESTONE MEMBER TO BUNGER LIMESTONE MEMBER The following section showing the interrnl from the Gonzales limestone to the Bunger limestone was measured on the south slope of Brushy :\lound. an isolated hill south of the Graham-Finis road about half a mile east of Connor Creek: Section showing interval from Gonzales limeStone to Bunger limestone on Brushy Mound, southeastern Young County. Thickness Feet Inches Conglomerate, base not exposed________________________________________ _ 15 Talus, probably shale_______________________________________________ 50 10. 9. Bunger limestone member____________________________________________________ 1 8. 7. Talus, probably shale________________________________________________________________ b 6 6 6. Sandstone ------·-----------------------------------------------------------------­ 5. Taius, chiefly shale_____________________________________________________________ 67 4. Sandstone, mas~iYe and bedded, not all exposed________________ 67 3. Sandstone, limy, massive, dark and pitted________________________ 2 2. Talus ________ ----------------------------------------------------------------------------------16 1. Gonzales limestone member_____________________________________________________ 10 24-t The interval from the top of the Gonzales limestone member to the base of the Bunger limestone member is 168 feet, to which must be added a thickness of 6 feet for the Bunger limestone, here only partly exposed, making the interval to the top of the Bunger 174 feet. The thick sandstone deposit, beds 3 and 4, which overlies the Gonzales limestone member is in many places extremely conglom­eratic. It rests unconformably on the underlying beds (fig. 2). On Brushy :.\lound, as shown in the section, there is an interval of 16 feet between this sandstone and the Gonzales. On the river bluff already mentioned, opposite Salem Bend, sandstone and conglomerate rest directly on Gonzales limestone. On the hillside north of the road from Graham to Henry's Chapel, three-fourths of a mile north­west of Connor Creek, the conglomeratic sandstone at its base con­tains pebbles of clay ironstone and limestone, which suggests that the top of the Gonzales has been eroded, though the contact was not seen. Ross,:~ in describing the Gonzales limestone at its type locality, in the Lacasa area of the Ranger district, 30 miles to the south, says: The top of the Gonza1es limestone is marked by a slight unconformity. In most of the area it is overlain by only a few inches of shale, aboYe which lies a very massive bed, the base of which is an intraformational conglomerate containing ferruginous clay pebbles. This grades into a conglomerate com­posed of light-colored chert pebbles with quartz sand filling the interstices, and this conglomerate in turn grades into a normal sandstone. 3Ross, C. S., The Lacasa area, Ranger district, north-central Texas: U.S. Geol. Su" ·,·y Bull. 726, pp. 307-308, 1921. He notes that the Gonzales limestone thins or is absent in the northern part of the Lacasa area and that the interYal aboYe the Home Creek limestone is "about 100 feet.'.' Campophyllum torquium is reported to be abundant in the Lacasa area, but none "·as seen 111 the Gonzales on Brazos RiYer. It sef'ms likely that a somewhat greater unconformity exists at the base of this sandstone oYerlying the Gonzales on Brazos Riwr than was obserYed by Ross in the Ranger district. The Gonzales limestone seems to be cut out by unconformity south and west of Salem Bend. and it is probably missing in other areas farther south. The conglomeratic sandstone deposit is less regular on Brazos RiYer than would appear from the description of the bed in the Lacasa area. The wrtical distribution of the conglomerate also is less regular, the thickness greater, and the top less "-ell defined. It passes into the shale of the upper part of the section by a series of beds of alternating sandstone and shale, and no sharp line can he dram1 at its top. The sandstone deposit, although sho"·ing unconformahle rela­tions at its base. sh(rn·s no sign of ha,·ing been deposited in channels in any of the places sf'en along the outcrop. It contains poorly pre­sen ed trunks and frag:mf'nts of plants in some placf's. but these are sporadic and rare. Thf' pebbles are similar to those in the Kisinger channel. The following: section. measured on the riYer bluff at the "·rst end of Haynes :\fountain. 2 miles north of Bunger on the east (left l side of Brazos HiYeL sho\\·s the sedimentation aboYe the thick sandstone. Scrtion belozc Bunger limestone north of Bunger. southern }"oung Count_•·. Thickne:'s Feet 9. C:nn~lonwrate: unrnnformable on bed 8 17 8. Bun~er limestone member___ 1 7. Shale 20 6. Limc;.;t11ne. thin bedded, earthy, sandy. fos,;:ilifrrous '.2 5. Shale and talus 42 ,!. Sandv limc"tnnc. with 2-inch crinoidal limc~tnne lan'r at top ('\o.rth Leon linw!'tone member?) . 2 3. Sandqone and shale alternating, poorly exposel -------·------29 2. Not ex posed ____ _ _ ___________ __ _ ___ __ ____ ____ ___ . _ 22 l. Sandstone, platy at top, massive below 9 Bed 1 probably lies at the top of the thick sandstone sheet above the Gonzales limestone member. The sandy limestone (bed 4) at 62 feet below the Bunger occurs near the horizon of the North Leon limestone member of the Lacasa area and, though thin and erratic, may be a northern representative of the marine invasion recorded by that member. It was not observed in place elsewhere, but float of similar character at about the same horizon is present in a small drain that discharges westward into Brazos River west of the high­way from Graham to Bunger, 11;2 miles north of Bunger. Bed 6, though earthy and thin bedded, is usually present where the horizon comes to the surface, but in some places it is cut out by channeling, as described below. In a small saddle north of the road from Graham to Henry's Chapel, a quarter of a mile southeast of Flat Rock Creek, 4 miles from Graham, several very fossiliferous beds 2 to 3 inches thick occur in the 20-foot interval below the Bunger limestone, but they were not noted elsewhere. The following section was measured on the hill west of Bunger at the type locality: Section of beds below Bunger limestone near Bunger, southern Young County. Thickness Feet 5. Bunger limestone member____________________________________ 2 4. Shale, weathered, yellowish _________________________________________________ 20 3. Limestone, earthy, sandy, fossiliferous, thin bedded, at top a very fossiliferous plate 2. inches thick, red in color________ 2 2. Shale, not well exposed__________________________________________________________________ 31 1. Sandstone, massive ----------------·--------------------------------------------------------5 60 BUNGER LIMESTONE MEMBER The Bunger limestone was named for its outcrop near the town of Bunger, 5 miles south of Graham, though much better and more complete exposures of it occur at other points, as on the west side of Brier Bend, at the base of Bass Mountain, and on Brazos River north of South Bend. It consists of a dense, hard, yellowish-gray, very fossiliferous lime­ stone weatheri~g to hard ringing slabs. On fresh surface it is dark and crystalline and shows many fusulinids. In general there are two separate benches in the outcrops, each about 1 foot thick, weath­ ering smoothish with rounded corners. In the best exposures, how­ ever, these resistant beds are joined to and underlain by 4 feet or BUNGER LMST z 0 ;:::: < :l a: 0 ,....... I­a: < a. NORTH LEON LMST u. a: :l < :I: \~_; :~~:;-/:·:.. .... ~ 400 ---=---=---=-----=---~~ =--=----=-------=--~~--=---=---=-.· ·. .· --~-=--= W L.~ ~'L!i.'.._~~. ,~.~..----==::--~~;;;::--------------­ .----=-----:-:-~~­ 350 ­ -----------------=-------=---------=-----=----=------------------­ 300 ··:·::.d::c;o,;····.:·. ··:::.~;:; • .:•·-•4t~:W7iif~.·i:· J·;t,::,f(f.,_.·1. '.c.tCcrtli~@&~=-dJ#i~ill ~2!>0 ~ 200 ~ ~ ~ < --IJ ~ w > 150 ~ HOME CREEK ~ Z LMST. . 100 a: 0 u ­ l­ o < ~-P:c':2.::.· ..:.'~li1f1~·...... ,,d:~·~~~·~~ 50 0 :l 0 a: < 0 u Li. 0 FT. RANGER LMST. Fig. 2. Diagrammatic cross section of Caddo Creek formation and lower part of Graham formation, southeastern Young County, Texas. Geology by Wallace Lee. more of less massive limestone, which in such places forms with it a striking and resistant rim rock more than 6 feet thick. The lower 4 feet, which is in few places well exposed, disintegrates in weather­ina and lets the more resistant members settle downhill on the soft 0 yellow slippery shale below. CHANNEL BELOW THE BUNGER LIMESTONE MEMBER On the bluff of Brazos River just west of the bridge on the high­way from Graham to Bunger, upstream from the mouth of Salt Creek, there is a fine exposure of a deep sand-filled channel (fig. 2). The following section was measured: Section in channel deposit below Bunger limestone. Thickness Feet 3. Bunger limestone member------------------------------------------------------------4 62. Shale ---------------------------------------------------------------------------------------------­ 1. 5andstonP (exposed down to edge of river alluvium) ___________ 56 This channel from rim to rim along the bluff is not over a quarter of a mile wide, but it is at least 56 feet deep, the base of the channel not being exposed. At most of the exposures below the Bunger there is no sign of unconformity, and a normal section including the limestone at 22 feet below the Bunger is present. However, at some localities sandstone of varying thickness but without obvious channeling occurs at this horizon. On the west side of Brier Bend, sandstone at least 8 feet thick is present 6 feet below the Bunger. At the old bridge across Brazos River north of South Bend 13 feet of sandstone occurs at this horizon, and thinner deposits occur at some other points. The channel, though filled with fairly coarse sandstone, contains no pebbles, and this fact, together with the depth and narrowness of the valley suggests that it may have been a tributary to a more extensive drainage system. Such inequalities as were produced by the erosion were effectively filled before the deposition of the Bunger limestone. BUNGER LIMESTONE MEMBER TO TOP OF WAYLAND SHALE MEMBER The interval from the top of the ~unger limestone to the top of the thin but persistent limestone bed at the base of the Wayland shale member is about 175 feet. The Wayland shale which is fol­lowed by an important unconformity has a maximum observed thickness of llO feet, thus giving the post-Bunger deposits of the Graham formation a known thickness of 285 feet. No less than nine unconformities, several of them involving general erosion and others deep channeling, were observed in this interval (Pl. II). As some of these erosion surfaces intersect others and as in most of them the inequalities of the erosion surface are leveled off, with the deposition of sandstone or conglomerate, it would be quite impossible to dif­ ferentiate between them if it were not for the fact that most of the sandstone deposits were followed by 'marine invasions during which thin deposits of fossiliferous limestone were laid down. The following sections show the normal sequence of deposits immediately above the Bunger limestone: Section on the road a quarter of a mile north of the cemetery in BrZ:er Bend. Thickness Feet 5. Slabs and plates of light-colored limestone, weathering smooth anr sect ion seems unwarranted. On the ol. soft. grav. laminated, impure -----------------------------1 2. Shale. Yariegated. with ironstone concretions in band_____ 8 1. Sandstone, massiYe and irregularly bedded, gray______________ 5 109 6 M_rnlina-bearing limestone of the aboYe sections is represented in the cross section of the HarpersYille formation (fig. 4) as deposited in channels formed subsequent to the deposition of the sandstone, though the eYidence does not preclude its deposition contempo­raneoush-with the sandstone. On the west side of Wagon Timber Branch at the crest of the escarpment on the road the Saddle Creek limestone is immediately underlain by 6 feet of coarse sandstone. In the road outcrop east of Huffstettle School. 11 ~ miles farther west, it is immediately under­lain by a shale section with streaks of coal and coaly shale. On the bluff of the first ridge east of the mouth of Kings Creek it is under­lain bY shale. Section of upper part of Harperst'ille formation on first ridge east of the mouth of Kings Creek. Thickness Feet Inches Pueblo formation: 7. Sandstone, forming bench ________________ __----------------------------4 6. Shale -----------------------------------------------------------------------------------12 HarpersYille formation: 5. Saddle Creek limestone member: Li mestone, earthy ---------------------------------------------------------· 4 Shale. gray, fossiliferous ---------------------------------------------1 6 Limestone, gray, crinoidaL__________________________________________ 8 Shale -------------------------------------------------------------------------------4 Limestone, brown, sandy, fossiliferous______________________ 1 4. Shale, with streaks of coaL________ __________________________________ 19 3. Sandstone. gray. thin-bedded______ __ ___________________________ _ ___ ____ 8 2. Shale. yellowish -------------------------------------------------------------16 6 1. Coal; base not exposed ------------------------------------------------3 63 7 Saddle Creek limestone member.-In the exposures on Wagon Timber Branch the Saddle Creek limestone member consists of a single bed of Yery earthy, tough, unlaminated dark limestone. It is about 8 inches thick and only sparsely fossiliferous, the fossils consisting chiefly of brachiopods and pelecypods. It weathers to rough, porous buff-gray boulders. Farther west from Huffstettle School and in the area near the mouth of Kings Creek, as shown in the above section, there are generally two similar limestone beds in the outcrop. In ordinary exposures they are buff-gray, tough, porous, and earthy. They weather to roundish boulderlike lumps and are seldom found exactly in place. In the cored well on the Graham ranch the horizon of the Saddle Creek is occupied by thick sandstone, and the limestone seems to be absent in the intervening area around the head of Fish Creek, where the Belknap limestone member has been confused with it. Limestone outcropping 2 to 3 miles north of the Nash & Windfohr pool is probably the Saddle Creek. The following composite section of the Harpersville formation shows the intervals between the principal beds, but the great variability of the sedimentation cannot be indicated in a single section. Composite section of the Harpersville formation, Donnell ranch, south­western Young County. Thickness Feet Inches 35. Limestone (Saddle Creek limestone member)------------------I 34. Shale, yellowish, limy________________ _ _____________________________________________ 6 33. Sandstone, platy, yellowish gray______ ___________ _ ________________________ 5 32. Shale, variegated, in places with coal streaks ------------___ 18 31. Sandstone, platy, brownish, soft_________________________________ __ _______ 34 30. Shale, variegated ----------------------------------------------------------------------33 29. Shale, yellowish, limy, fossiliferous______________________________ _ _____ 2 28. Limestone, greenish gray, crystalline, fossiliferous (Belknap limestone member) __ _________________ __________________________ 1 6 27. Shale --------------------------------------------------------------------------------------------10 26. Sandstone ---------------------------------------------------------------------------------2 6 25. Shale, variegated -----------------------------------------------------------------------8 6 24. Sandstone, limy ___________ --------------------------------------------------------------8 23. Shale ------------------------------------------------------------------------------------------3 6 22. Limestone, lenticular, crinoidaL__________________ __ __ _______________________ 4 21. Shale ____ _________ ______ --------··-···---------------------------------------------------------5 20. Sandstone, yellowish, flaky__ _ ___________ ___________________ _________________ I 19. Clay, gray-white -------------------------------------------------------------------------6 18. Sandstone, brown, platy, top of channel deposit __ ________ __ _. 4 17. Shale, gray, sandy__ ______ -------------------------------------------------------------4 16. Limestone, earthy, and flaky_________________________________________________ 6 15. Limestone, gray, crystalline, fossiliferous ____________________ ___ _ 1 14. Shale, limy, fossiliferous__ _________________________________________________________ 4 13. Shale, carhonaceous ------------------------------------------------------------------I 12. Coal and shale____________________________________________________ _______________________ 2 74 The University of Texas Publication No. 3801 Thickness Feet Inches 11. Shale -----------------------------------------------------------------------------------------12 10. Limest~?e, buff, fossiliferous ("Upper Crystal Falls lime­stone ) ---------------------------------------------------------------------------------2 9. Shale --------------------------------------------------------------------------------------------2 8. Coal and shale; local development_______________________ ______________ 3 7. Shale ---------------------------------------------------------------------------------------18 6. Septaria ------------------------------------------------ ----------------------------------------1 5. Shale ________ _____ ---------------------------------------------------------------------------4 4. Limestone, in two benches separated by shale (Crystal Falls limestone member) -----------------------------------------------------4 3. Shale ------------------------------------------------------------------------------------------18 2. Limestone ("Cl" bed) ______________________________________________________________ 5 1. Shale, red --------------------------------·---------------------------------------------------15 Breckenridge limestone member of Thrifty formation. 233 PUEBLO FORMATION The Pueblo formation includes the beds from the top of the Saddle Creek limestone to the top of the Camp Colorado limestone (Pl. IV). No opportunity was afforded to check the identity of the Camp Colorado limestone member, and the work of the cooperative map­ ping committee of the American Association of Petroleum Geologists in correlating this member on Colorado River with the outcrops in Throckmorton County has been accepted. The Pueblo formation as so defined is 207 feet thick on Clear Fork of Brazos River. Saddle Creek liniestone member of Harpersville formation to base of Camp Colorado limestone member of Pueblo fonnatian.-The lower half of the Pueblo formation is distinctly sandy in character, whereas the upper half is predominantly composed of shale. Up to the middle of the formation the sequence continues variable, as in the Harpersville formation, and contains increasing numbers of lenticular sandstone bodies, which are characterless and without notable continuity and in few places as much as 15 feet in thickness. Not uncommonly the topmost layer of the sandstones shows the worn remains of pelecypods, in some places altered by iron car­ bonate. The limestone beds that are present are only 2 or 3 inches thick, impure, nonfossiliferous, and discontinuous. The shales are variq.!atcd and rou:-; earthy lime-.tone lenses 2 to 4 inche,.; thick --------------··---­ 16 4. Sand,.:t(lnt'. mas,.;in'. ferruginou s. ch~ngi1;~:---l-<~ lam­i1wted gray ,.;and--tonf'; in places has ;mall limy Thickness Feet Inches pebbles cemented in red-brown limonitic sand; in places dark and calcareous._____ _ ____ ______ __ ______________ 2 3. Shale, fissile, lilac-colored, carbonaceous, with yellow limonite partings; upper 3 feet sandy ___ _ --··------16 2. Sandstone, dark, ferruginous, weathering purplish; breaks down to yellowish chips and flakes __ __ ____ _ 3 l. Not exposed; probably shale ----------------------------------------9 Harpersville formation: Saddle Creek limestone member. 207 The Stockwether limestone member of the Colorado River sec­tion, which occurs in the middle part of the Puehlo formation, could not be positively identified. It may be represented by a thin brown earthy fossiliferous limestone (bed 14 in the above section) that lies 105 feet below the Camp Colorado limestone and is best exposed in a small drain a mile east of the Breckenridge-Throck­morton highway just north of Clear Fork. PERMIAN SYSTEM WICHITA GROUP REDEFINED (BASAL PART) The Moran and Putnam formations were placed in the Pennsyl­vanian Cisco group by Plummer and :Moore and were formerly so classified by the United States Geological Survey, but the Texas Bureau of Economic Geology now considers them to belong to the Permian Wichita group." They are so included in this report, but the Permian-Pennsyl·rnnian boundary of this region is still a debated question. l\IORAN FOR:\IATlON Camp Colorado limestone member of Pueblo formation to Sed­wick .imestone member of Moran formation.-The Moran forma­tion is 213 feet thick. At its top is the Sedwick limestone mem­ber, and at its base is a sandstone deposit, with which some shale is interstratified, resting unconforrnahly upon the underlying Camp Colorado. In some places a few feet of shale rest conformably on "Sellards. E. H .• Adkins. \\'. S .. ond Plummrr. F. B.. Tl:c G,·olo!!y of TC'xas. Yol. J, Stratig­ rnphy: l:niL Tt•x. Bull. 3~32, pp. 110-111, 1 91~ [lfJ.1.1]. the Camp Colorado below the unconformable sandstone, and this shale, as it lies below the unconformity, should properly be con­sidered a part of the Pueblo formation, but in this area the over­lap is negligible (Pl. IV). The lower half of the Moran formation, like the lower half of the Pueblo formation, contains many thin lenticular sandstone beds, unconformable at their base. The upper part is also similar to the upper part of the Pueblo formation in that it consists very largely of shale. Both parts of the Moran, however, contain numerous fossiliferous limestone beds, which are rare in the Pueblo. As the basal sandstone deposits of the Moran are underlain by the thick shale section of the Pueblo, they form the top of an escarpment which cuts across the region from southwest to north­east. In the lower 100 feet of the formation there are four or more impure fossiliferous limestone beds from 8 to 18 inches thick, but they are nearly all followed closely by unconformable sand­stones, none over 15 feet thick, which cut out the limestones from place to place. As the limestones are all similar in general character and are interrupted along the outcrop they are very diffi­cult to follow and are best identified by their position under the sandstone benches, which can be followed more easily. These lime­stones are generally gray, in sharp contrast to the limestones in the upper half of the Moran formation, which in places are bril­liantly yellow. The upper 100 feet of the formation consists chiefly of shale interstratified with thin limestones. The shale beds are exposed in few places and, as the limestones are not very resistant, the result­ ing topography is rolling. The limestones of the upper part of the Moran formation are earthy and fossiliferous and generally dark gray, weathering to rather brilliant yellow or brown, with smoothish surfaces on exposure. They occur at intervals of 20 to 30 feet and form a group that in color is unlike the limestones of any other part of the section. Sedwick limestone member.-The Sedwick limestone, at the top of the formation, consists of two limestone beds, each about 1 foot thick, separated by 7 feet of shale. These beds, which are similar in texture and color to those below, are distinguished by the presence of silicified fossils, chiefly small gastropods. The lower bed also contains small amounts of diffused chert. Good outcrops of this bed occur on a crossroad south of the schoolhouse 31/~ miles west of Woodson, where the bed is repeatedly exposed in and along the road for a distance of 1% miles. The following composite section was measured by plane table from the escarpment crossed by the Breckenridge-Throckmorton highway in southeastern Throckmorton County to the vicinity of _ the school mentioned above. The lower part was measured in the basin of Rust's Kings Creek, southeast of Woodson. Composite section of Moran formation in southeastern Throckmorton County. Thickness Feet Inches 35. Sedwick limestone member: Limestone, thin bedded, buff; contains tiny silicified gastropods ----------------------------------------------------------------------------1 Shale, limy -------------------------------------------------------------------------7 Limestone, dark gray, crystalline, weathering buff and yellowish; contains diffused chert and silicified gastropods; other fossils include numerous Myalinas 1 34. Not exposed; probably shale_________________________________________ ______ 21 33. Limestone, drab to gray, weathering buff, with rough · pitted surface, nonfossiliferous____________________________________________ 1 32. Not exposed; probably shale___________ ________ __ ______ __________ ___ ___ _____ 23 31. Limestone, medium crystalline; color varies from light gray to dark brown and chocolate-brown, weathering to smooth yellowish surface; upper part has finer texture and no fossils; lower part laminated and fos­siliferous ----------------------------------------------------------------------------------1 30. Shale --------------·----------·------------------------------------ -----------------------------30 29. Limestone, earthy and sandy, fossiliferous; locally car­ries Myalinas --------------------------------------------------------------------------6 28. Not exposed; probably shale__________________ __ ______ ________________________ 3 27. Limestone, dense, crystalline, very dark, weathering to drab, gray, buff, bright yellow, or brown, fossiliferous__ 1 26. Not exposed; probably gray shale_________________ ______________________ 6 25. Sandy shale, with macerated leaf fragments, in places 10 feet or more thick; apparently cutting into under­lying sandstone ----------------------------------------------------------------------6 24. Sandstone plates and soft sandy shale in bands with small tidal channels filled with sandstone every hun­dred yards along road cuts -----------------------------------------------9 23. Not exposed; probably sandy shale_____ ______ _____________ ___________ 17 22. Sandstone, thick bedded and cross-bedded; contains lenses of conglomerate of earthy nonfossiliferous limestone; 20 feet or less in thickness ; where thick, the beds below are cut out --------------·· .. ·----------------------13 21. Shale, yellowish, limy, capped with residual lumps of leached Luff, earthy nonfossiliferous limestone; thick­ness varies ------------------------------------------------------------------------3 Thickness Feet Inches 20. Lime,;tone, crystalline, fossiliferous, gray to Lrown, weathering away easily; basal part earthy and sandy 6 319. Not exposed; probably shale __ ------------------------------------­ 18. Sancbtone, hard, limy, and ripple-marked; this bed is more pers:stent locally than the associated limestones; the thickne:"s is as much as 3 feet or more; it usually forms a bench _____ ________ _ _ __ --------------------------1 17. Sandstone, limy, in plates and flakes --------------3 16. Limestone, crystalline, gray, brown, and yellow; in places this bed is grainy and peLbly and contains broken fossils; discontinuous -----------------------------------------1 6 15. Shale, yellowish, gra y, weathered--------------------------------------6 14. Not exposed; probably shale----------------------------------------------5 13. Red shale ___________ -----------------------------------------------------------------------8 12. Clay shale, bluish drab _ _____ ___ ---------------------------8 1l. Sandstone, flaky, bleached white __ ____------------------------------­ 10. Sandstone, platy, specked with ironstone---------------------6 9. Not exposed _ _ _____ ________ __ -__ ------------------------------------7 6 8. Limestone, impure, fossiliferous --------------------------------------------6 7. Not exposed ___ _----------------------------------------- ----------------------------------11 6. Limestone, earthy, platy, fossiliferous ---------------------------------6 5. Sandstone, reddish; forms a bench __ __ _____ _ ______ ___ _ _______ ___ 2 4. Not exposed ____---------------------------------------------------------------------------9 3. Sandstone, in plates 1 to 3 inches thick ____ ___________------------1 2. Sandstone, shaly _-------------------------------------------------------------------­1 !. Sandstone, in plates 6 inches thick------------------------------­1 Camp Colorado limestone member of Pueblo formation. 215 6 A sen es of tidal channels filled with sandstone are exposed m successive road cuts along the highway l % miles southeast of Woodson. PUTNAM FORMATION Sedwick limestone member of Moran fonnation to Coleman ]unc­tion limestone member of Putnam Jormation.-The identification of the Coleman 1unction limestone member-the top of the Putnam formation-by the cooperative mapping committee of the Amer­ican Association of Petroleum Geologists is herein accepted. (See Pl. IV.) In southwestern Throckmorton County the Putnam forma­tion is 205 feet thick. Practically the whole of the section is shale, though the lower part, which crops out under the outwash at the base of the Coleman ]unction escarpment, was not seen. The shale is for the most part mildly variegated in color, and in the upper 50 feet there are some thin, inconspicuous sheets of fine-grained sandstone involved with irregularities of deposition that suggest contemporaneous erosion. At 51 feet below the Coleman Junction limestone there is a bed of very earthy limestone about 1 foot thick, which carries a gastro­pod fauna. This bed was noted north of the point where the high­way west from Woodson crosses the escarpment. It is discontinuous and seems to have been eroded and replaced locally by a thin deposit of red shaly sandstone, which elsewhere lies immediately above it. Colenwn function lirnestone niember.-The Coleman Junction limestone member in southern Throckmorton County is only 15 inches thick. It is dark and fine textured, weathers to dark gray, yellow, or chocolate-brown, and is fossiliferous, though collecting is difficult, for it is resistant to erosion and weathering. Its resistance, combined with its position above the thick shale section of the Put­nam formation below, results in a strong escarpment, the most prom­inent topographic feature of the county, striking across the region from southwest to northeast. The following composite section was measured along the road west from Woodson in Throckmorton County: Composite section of Putnam formation west of Woodson, Throckmorton County. Thickness Feet Inches 30. Coleman Junction limestone member -----------------------------------1 3 29. Shale --------------------------------------------------------------------------------------------5 28. Sandy limestone, smooth textured, gray, nonfossiliferous, weathering to fine sandstone ---------------------------------------------l 27. Shale, weathered ----------------------------------------------------------------------19 26. Shale, limy, yellowish, gray, and greenish______ ___ _____ __ _________ _ 20 25. Shale, red ----------------------------------------------------------------------------------2 24. Earthy limestone, weathered to leached red crusts, non­fossilifero11s ----------------------------------------------------------------------------6 23. Sandstone, red, flaky______________________________________ __ _______________________ _ 6 22. Shale ------------------------------------------------------------------------------------------2 21. Limestone, earthy, dense, greenish, weathering to leached brown porous lumps, fossiliferous, containing especially gastropods --------------------------------------------------------------------------------1 20. Shale, red and brown ------------------------------------------------------------1 19. Sandy shale, greenish---------------------------------------------------------------3 18. Sandstone, fine grained, greenish__ ____ _____ __ ________ __ ______ _ ________ _ l 17. Shale, greenish ---------------------------------------------------------____ _ ________ _ 5 6 16. Shale, limy, forming a band __ ______ __ ____ _____ ___ ___ _____ __ ______ ___ ________ _ 3 15. Shale, greenish ------------------------------------------------------------------------1 14_ Shale, purplish and gray--------------------------------------------_________ _ 3 6 13. Clay, with small chalky concretions where weathered __ _ l 12. Shale, brown, coaly, with purple and yellow partings __ 1 84 The Unirersity of Texas Pul>lication No. 3801 Thid.. ness Feet Inches 1 6 11. Shale, bluish, coaly, brown partings-----------------------­ 10. Clay shale. oliYe-g:reen __________________________------------------3 9. Shale. fissile. bluish and brownish, coaly__________ _____ -----------3 8. 1\ot exposed : probably shale ----------------------------------------------­47 '. Sandstone. soft, reddish gray ---------------------------------------------1 6. Sandstone. limy. in flakes and plates --------------------------------1 ;:>. :\ot exposed: probably shale _______ -----------------------------------------15 4-. Limestone conglomerate, composed of small pebbles, nonfossiliferous earthy limestone. lenticular _________________ 1 3. Shale, limy, bluish gra·y___ __________ __ _:___________________________________ __ 3 2. Sandstone, limy. greenish; weathers to flaky laminae _ _ 3 1. ::\ot exposed: probably shale: local deposits of lime­ stone conglomerate near base-------------------------------------------57 Sedwick limestone member of ~loran formation. 205 SCl\l\IARY OF FORMATIONS The following: list shows the thickness of formations measured along Brazos Rinr in Young, Stephens, and Throckmorton counties. Cnconformities are indicated only where they occur between the formations. Details of the sedimentation are shown in the columnar section t Pl. IV). Thickness of formations along Bra:.os Rfrer in l'oung, Stephens, and Throck­morton counties. Feet Permian sYstem: \\-ichita group redefined 1basal part) (4-18 feet) : Putnam formation 205 :\Ioran formation _ 213 r nconformity. Pennsyhanian svstem: Cisco group restricted (11-18 feet) : Pueblo formation _ 207 r n·:onformitv. Harpersville -formation ________--------------------------------------___ 233 Tbr!ft~-formatiun I top of Breckenridge limestone to top ot :\o. 9b lime~tone of \\·aYlan!s, south of Colorado River (Upp Pr P<'nnsylrnnian and ]ow,·r Permian Sl'l'tion of Colorado Hiver valky, Tex as: t:niv, TPxas Bull. 3501. p. 191. 19:l'; l19:lS the area to Colorado RivPr, where at the type locality they ar(' b..Jow the Chaflin limC',tone correla ted with the Brcckenridg<'. :\o ml'ntion is made of the B1·ll<'roph on h.-d south of the beds. Cheney,:? in 1932, suggested the correlation of the Palo Pinto with a thin yellow limestone 100 feet above the Capps limestone.3 This change in correlation, of course, augments the thickness of the Strawn, throwing into that group the Capps limestone and a considerable part of the shale that was formerly included in the lower part of the Graford formation when the horizon of. the Palo Pinto limestone was considered to be below these beds. The Capps limestone is here treated as a member of the Mineral Wells for­mation, the upper formation of the Strawn group. The older Ricker sandstone is also a member of the Mineral Wells formation. Ricker sandstone member.-The Ricker member is composed of sandstone and conglomerate, and is undoubtedly an unconformable deposit laid down after one of the periods of erosion that were so frequent in Pennsylvanian time in this region. It was named by Drake for a post office east of Brownwood and is shown at the base of the section measured near Brownwood. This bed corre­sponds closely in position with a sandstone bed in the section measured by R. T. Hill 10 miles farther north, but toward the south the conglomerate bed at the mouth of Clear Creek (bed 13 of the Winchell section, p. 99), identified by Drake as the Ricker, seems to be considerably higher in the section. (See fig. 6.) On State highway No. 7, 6 miles east of Brownwood, near the type locality, the Ricker member consists of 6 feet of conglom­erate and an estimated thickness of 20 feet of sandstone beneath it. The conglomerate is irregularly stratified, coarse sandstone and conglomerate grading upward into brown sandstone. It contains some dense, hard, fossiliferous limestone pebbles 3 inches or less ri\'cr and thonf'.h con

?~ ............... Pft0BA8Lf OIL SANO or THE 8AOWNWOOO IHALLOW POOL Fig. 6. Comparison of measured sections of lower part of Graford formation (redefined) and upper part of Strawn group in Brown County, Texas. in diameter and many small pebbles of chert-red~ brown, yellow­ish, white, purple, gray, and a few black and green. The green pebbles are not so abundant as in higher beds that have been called Rochelle conglomerate by Drake and by Plummer and Moore. In the Winchell section there is considerable sandstone and con­glomerate at horizons marked by shale at Brownwood. Although Drake considered the sandstones and conglomerates of the ·Winchell section to be the equirnlent of his Ricker bed of the Brownwood area, it would seem more plausible to correlate them in part with the zone of conglomeratic beds of the Brownwood section (fig. 6). The area south of Colorado River was not examined, but it seems not unlikely that the upper part of the coarsely elastic beds in the \\-inchell section is more or less contemporaneous with the Rochelle conglomerate of Drake, whose principal outcrops are to the south. Capps limestone member.·-The Capps limestone is a lenticular deposit of small area and considerable variation in thickness and texture. Where exposed on highway No. 7, 6 miles east of Brown­wood, it has a thickness of only 10 feet, a considerable part of which is shale, but thicknesses as great as 40 feet have been re­ported. At this locality it includes three limestone beds, of which the lo,rest, 4 feet thick, is gray and highly fossilifemus. The mid­dle bed, separated from the lowest by 2 feet of gray shale, is 1 foot thick, brown, deme. and crystalline and carries few if any fossils. The upper bed. 1 foot thick and underlain by 2 feet of gray shale, is gray. dense, and crystalline and carries but few fos­sils. The Capps limestone occupies small areas east of Brown­wood but is so erratic in distribution that it is of little value as either a surface or a subsurface datum. A thin limestone near the base of the section at Winchell (bed 3, p. 100) , which occurs at about the same horizon. may be its southern equivalent, though else,rhere in the \\rinchell area the bed, if present, is not generally exposPd. In the Brownwood area it is separated from the top of the Ricker member by 30 feet of gray shale, near the base of which there is a small coral reef, exposed in the road cut. CANYON GROUP The following table shows the subdivisions of the Canyon group in the Colorado Ri,-er Basin as presented by Plummer and Moore m 1921 and more recently by Sellards, Adkins, and Plummer in 1933. The descriptions of the formations that follow are based chiefly on the divisions indicated m the later report. Plummer and Moore·! Sellards, Adkins, an>->•'C!ion is that measured the outcrPpS. The thickness indira\t'd by well logs shows the Brad on Colorado 142 The University of Texas Publication No. 3801 section, however, is shown in the sketch a little farther south than its true geographic position, so that the convergence is actually a little sharper north of the Lacasa area and more gradual south of Lacasa than shown. The interval from the Bunger limestone to the top of the Home Creek limestone is 303 feet in the Brazos River area, in southeastern Young County. In the Lacasa area, 30 miles to the south, on the line joining the lower Graham section of Brazos and Colorado rivers, the intenal is 178 feet. In the Ranger area,6 about 10 miles farther south, the interval has increased to 255 feet. The beds of this interval thin again between the Ranger area and southeastern Coleman County on the Colorado River until they nearly disappear. From the Bunger limestone down to the base of the Canyon group the thick limestones either thin or finger out in the line of the section toward the south. The thinner limestones, such as the Gonzales and North Leon limestone of the Ranger oil field section, thin and dis­appear and the shale beds between them thin also. The Gonzales limestone in the Lacasa area of the Ranger district, as reported by Ross, is stratigraphically closer to both the over­lying Bunger limestone and the underlying Home Creek than in Young County. Not only is this true, but the overlying conglom­eratic sandstone is thinner and its top is closer to the Bunger lime­stone in the Lacasa area than in Young County. These differences seem to indicate that the Young County area was subsiding faster during this interval than the Lacasa area, and the thinning of the corresponding shales in Brown County suggests that the Gonzales limestone, the North Leon limestone, and possibly the Bunger lime­stone, overlap on the margin of the subsiding basin and were never deposited in southern Brown County. Insofar as there is uncertainty as to the exact position of the top of the Home Creek in southern Brown County, there is a correspond­ing uncertainty as to whether the Bunger limestone, which was deposited near the close of the subsiding movement, is represented in the Colorado RiYer section, where it has not been positively identified. There seems reason to suspect that the Bunger limestone, Rivrr of arrroxim1klv the same thrkness as the Brad in the Bun~Pr P ool in the Brazos basin. There is therefore no convergence in the Brad formation. 6Ree,·cs. Frank, Geology of the Ranger oil field, Texas: U.S. Geo]. Survey Bull. 7::16, p. 115, 1922. like the Gonzales and the North Leon limestones, overlaps the mar­gin of the flexing basin and disappears, though it may be repre­sented by the yellow limestone at the base of the Graham in the Colorado River section. If later work shows that the equivalent of the Home Creek of the Brazos area has been placed too high in the Colorado River section, it may even be represented by one of the gray limestones there included in the upper part of the Home Creek limestone. Such a development would not, however, modify the general conclusions. The relation of the beds in the lower part of the Graham formation to each other indicates that the warping during Canyon time con­ tinued into the lower Cisco. After the deposition of the Gonzales and its subaerial exposure and partial removal the region was again warped. The trough so formed was filled to a certain level with sand and gravel derived from the rising terrane to the east (the southwestward extension of the Ouachita Mountains). The surface of the sandstone deposit was evidently warped or flexed in the same way as lower datum beds and covered by shale, which was in turn followed by the recurrence of marine deposits (the Bunger limestone). There appears to have been only slight warping of the Bunger limestone and the immediately overlying ammonoid zone but with these movements the subsidence to the east, which had been going on since early Strawn time, came to an end so far as the direct record shows. Whether the flexing actually ceased at this time is open to ques­ ticn, for in both Young County and Brown County the parallel series of beds of the upper Cisco 'vere measured west of the axis of the Bend flexure. The eastward extension of the upper Graham, Thrifty, and Harpersville on the active side of the axis of the Bend flexure has now been lost by erosion, but it is possible that these beds now eroded east of the axis might have shown convergence in that area. The Canyon beds in the Cross Cut-Blake area west of the Bend axis, as shown in the report of Edgar D. Klinger to be published elsewhere, are essentially parallel, although east of the axis they show divergence. The regular subsidence of the northern area with respect to the south is indicated throughout the Canyon group by the convergence between the principal beds and by the thinning and fingering out of the limestones toward the southern area. The Palo Pinto limestone, 144 The Uni'versity of Texas Publication No. 3801 the Winchell member, and the Home Creek limestone although not correlated without question between the two areas, tend to split up toward the south into a series of thinner limestone beds separated by shale in such relations as to suggest the approach in this direction to a land mass on whose flank the advance and retreat of shaly sedi­ments interrupted the continuous deposition of limestone. The cross section, as it \s based on only two areas, gives the impression that the convergence varies geometrically with the distance, a con­dition that probably does not exist, the rate of increase in thickness toward the north probably being variable. The cross section is based on a north and a south section and therefore gives the impression that the changes took place in this direction. As a matter of fact the line joining the two measured sections is diagonal to the structural movements of the time and actually expresses in a qualitative way changes which actually oc­curred in a more nearly east-west direction, the northern section expressing in a qualified way changes taking place basinward to the east, and the southern section the more static conditions toward the west. Cheney's work7 shows that the Strawn group thickens into a synclinal area west of and parallel to the extension of the Ouachita belt of Paleozoic rocks (fig. 9) . The flexing of the Canyon and lower Cisco beds is believed to express the continuing deformation and uplift of the same movement. The fact that Ouachita Mountain pebbles are present in most of the sandstone deposits up to late Harpersville indicates the continued elevation of the source area at least till that time. Presumably the flexing recorded in the convergence of the early Cisco and Canyon was the continued expression of the more pro­nounced movements that took place in the Strawn. The subsidence of the synclinal basin postulated by Cheney seems to have been gradual, more or less regular, and recurrent, as indicated by the consistent convergence between recognizable datum beds that were deposited on its margin. Along with these movements, however, there occurred others which seeming I y had no definite relation to them, for they took place during the period of subsidence not only in the 7 Chcncy. :\!. G.. Stratil(raphic and structural stucliPs in north-central TPxas: Univ. Texas Bull. 2913, pk 3 and 8, 1929. Stratigraphic and Paleontologic Studies 145 areas of convergence but also affected the parallel formations on the structurally static west side of the Bend axis in the upper Cisco. These movements resulted in the advance and retreat of the sea and are expressed in a series of unconformities, filled channels, beds that represent the pulsating advance and retreat of limestone and shale deposition, and other features. As these movements alternated throughout the period of differential subsidence of the synclinal area flanking the Ouachita belt of Paleozoic rocks and affected also the static area west of the Bend axis, it would seem that the fluctuations of sea level were independent of the immediate obvious local structural movements. Fig. 9. Sketch showing the relation of areas studied to certain structural features of the region. (After Miser.) Looked at as a whole, the stratigraphic column presents a record of almost continuous rise and fall of sea level. Some of the fluctua­tions were expressed in changing types of sediments, others by un­conformities, by terrestrial deposits with tree trunks in place, by impure coal deposits, by tidal channels, and by marine deposits in a bewildering and disorderly sequence. It is axiomatic that the sedimentary deposit of elastic material indicates erosion at the place of origin of the sediments, which have been transported from a land area and distributed and sorted by river, current, wave, and tide. The region from which they came 146 The University of Texas Publication No. 3801 must have been eroded in tidal channels or sleep-sided ravines, or else it must show maturely eroded surfaces, depending on the length of exposure, hardness of rock, gradient, and other factors. Several of the erosion surfaces noted in the Cisco of the Brazos Valley have a relief approaching or exceeding 100 feet. Withdrawal of the sea far enough to provide a gradient for erosion of this magnitude might well be expressed in hundreds of miles. If the surface were tilted the distance would be less, but there is no evidence in the late Cisco of any tilting and very little in the early Cisco. It has been suggested that submarine scour of land streams might be effective in producing these surfaces, but even if it could be demon­strated that such continents and rivers existed this explanation seems to be eliminated by the fact that at least some of the unconformable sudaces were not merely channeled but maturely dissected. The deposits of the post-Bunger No. 2 cycle, for example, occupy a basin about 100 feet deep and not less than 10 miles wide. Other surfaces, such as that preceding the No. 7 cycle, the No. 9 cycle, and the Avis sandstone, show mature dissection. The Kisinger channel is cut through the Home Creek limestone, a 50-foot limestone bed, and its bottom is eroded into the Ranger limestone. The Home Creek was already hard enough to break off in huge solid blocks on the side of the channel during the erosion period, and there is no reason to suppose that the Ranger was not equally consolidated at the time. Such erosion seems to indicate a subaerially eroded valley, for a submarine current, not being dependent on gradient, would tend to broaden its channel in the softer shale beds rather than erode hard limestone. The size and velocity of the submarine current demanded for submarine erosion of the Kisinger and other channels would in any case seem to eliminate it as an explanation. The weight of evidence seems to favor the withdrawal of the sea from the areas, even though this involves extraordinary fluctuations in sea level. At the time the Kisinger channel was being eroded the Ouachita Mounta.ins were still being raised and folded. The synclinal area which flanked the Ouachita belt of Paleozoic rocks to the west and north and in which in Texas the Strawn beds had been deposited was still ~-uhsiding. The abrupt tapering of the Kisinger channel towa d the west indicates that it had a general easterly course and that the stream was not long. It probably drained into the inter­mittently subsiding synclinal basin to the east at a time when down­ward flexing had renewed the synclinal trough and simultaneous withdrawal of the sea had given the margin of the static area west of the syncline a definite topographic relief. After erosion the basin may have been filled with outwash deposits advancing from the east from the coincidentally elevated Ouachita belt with or without the return of the sea. The source of the chert pebbles is definitely to the east, and, by whatever means it was accomplished, it is a fact that the coarse debris ultimately reached across the basin and was deposited in the dissected area on the west side. A possible example of how this may have been effected is illustrated by the conglomeratic sandstone overlying the Gonzales limestone, as shown in the cross section (Pl. X). The relations strongly suggest either the filling of an eroded and warped basin or the conditions represented by the Avis sandstone, mentioned below. If the synclinal basin east of the axis of the Bend flexure con­tinued to subside during late Cisco time, an explanation might be afforded for the localization of the erosion cycles on and near the axis of the flexure in much the same way as suggested for the Kisinger channel~that is, by downwarping east of the axis and simultaneous withdrawal of the sea, placing this area at the crest of a gentle eastward slope. In the absence of proof of late Cisco flexing east of the Bend axis, such an explanation, however plausi­ble, is speculative, but all theories seem to call for remote with­drawal of the sea during the erosion periods. The Avis sandstone, as shown in Plate X, furnishes an example of how some of the sandstones and conglomeratic beds may have been originally distributed. The top of the Avis sandstone is the one datum above the ammonoid zone that fails to show parallel­ism. This sandstone west of Graham extends upward almost to the horizon of the Blach Ranch limestone, and its upper surface is deeply dissected. On Colorado River the sandstone that corre­sponds in position to the Avis sandstone is conformahly overlain by the Bellerophon limestone. The relations suggest that the Avis may have been deposited as an alluvial plain, the deposits slop­irnr basinwroductus" (Linoproductus) sp. undet., fragments of a sma11 form (r) "Prolds of large form (c) "Orthoceras" sp. undet., section in rock (r) Phillipsia? sp. undet., part of a pygidium (r) Collections fr01n the Gunsight limestone member (fossil zone 4a Cb) -According to Plummer and Moore, the Gunsight lime­stone member consists, at the type locality, which is about 40 miles southwest of Graham, and at most places in the Brazos River val­ley, of two limestones separated by about 20 feet of shale or of 176 The University of Texas Publication No. 3801 shale and sandstone. These limestones, it appears, have been cor­related by different geologists with different beds in the region of Graham, and it is difficult to tell which limestones studied there are the Gunsight limestones. Many geologists have assumed that the presence of an abundance of Campophyllum torquiu1n (Owen) in a limestone between the shale immediately overlying the Bunger limestone and the Wayland shale was sufficient to warrant its identification as Gunsight. Lee's investigations, however, have shown that this coral is abundant in more than one bed. Because the stratigraphic positions of the various Campophyllum·bearing beds in the Graham are not very widely separated, the assumption mentioned has not made great discrepancies in maps of larger structural features. It has, however, caused errors that may be of great importance in mapping local structure and in determining the details of geologic history. Six collections were made from the Gunsight limestone member at or near the type locality in order to see if faunal peculiarities could be discovered that would provide a means for identification of the Gunsight limestones in the area near Graham. One of these collections from the lower limestone of the member contained only fusulinids. Of the other five, three ( 7500, 7551, and 7553) came from the upper limestone of the Gunsight member and two ( 7502 and 7552) from the lower limestone. Two of the collections (7500 and 7551) from the upper lime­stone came from a place about 150 yards south of the post office at Gunsight; the other came from the north edge of Gunsight, about 500 yards north of the post office and across the road north from a cemetery. The following composite list contains the species m all three collections: Fusulinids (r) Campophyllum d. C. torquium (Owen), small individuals (r) Syringopora sp. undet. (r) Crinoid columnals (r) Echinoid plates and spines (r to c) Brywan. fenestelloid. nonporiferous side (r) "Productus" (Dictyoclo;;;tus?) sp. undet., immature individuals (r) Spirifer ( :\' eo:::pirif er I triplicatus Hall (r) Dielasma boYidens? ('lartin I. young (r) Composita subtilita (Hall l ( n : I The two collections from the lower limestone came from a sin­gle locality, along the old Gunsight-Eastland road at a point about 2 miles south of Gunsight. These collections contain the following forms: Fusulinids (a) Syringopora sp. undet. (r) Crinoid stems (r) Echinoid spines (r to c) Echinoid plates (r) "Productus" (Dictyoclostus?) sp. undet., fragmentary young (r) Composita subtilita (Hall) (vc) Gastropod, possibly Meekospira, very much crushed and fragmentary, one specimen The small number of recognizable larger invertebrates in the limestones of the type Gunsight makes their correlation with beds in the Graham area by means of these fossils a difficult task. Nearly all the beds near Graham have larger and more varied faunas than either of the type Gunsight limestones. No bed from which the writer has collected in the Graham area suggests the upper Gunsight, and it may be either not present there or so changed lithologically and faunally that it cannot be recognized. There are some resemblances in fauna and lithology between the lower Gunsight and the limestone of No. 7 post-Bunger cycle but these resemblances are very slight, and when the variability of Pennsylvanian limestones and their faunas in this region and the totally inadequate nature of the lower Gunsight fauna are consid­ered, it is very evident that no adequate basis for the correlation of these two limestones exists. With the knowledge at hand, it seems slightly more likely that, if the lower Gunsight is repre­sented in the Graham area, it is the No. 7 limestone rather than one of the other limestones, but this suggestion rests on very slender evidence. Large fusulinid collections were obtained from these beds, and it is possible that they will give some basis for the correlation of the Gunsight limestones. Collections from No. 9 post-Bunger cycle liniestone (fossil zone 4 Cb) .-As treated in the first part of this report, there are three limestones in the :.\'"o. 9 post-Bunger cycle. The lowest of these is desianated the "A"o. 9 limestone." A limestone designated the "No. t" 9a limestone" occurs above No. 9, and one designated "No. 9b limestone.. is aboYe :\o. 9a. A. H'rY fossiliferous zone in the \·Vay­land shale occurs between limestones :\os. 9a and 9b. Onh one collection. 7+-1-3. wa:-obtained from the l\o. 9 lime­stone. It came from beds near the head of Kickapoo Creek. The species in it are as follows: f u;:.ulinid;:. ma gray.-illense C::\"orwood and Pratten1 (c) Phanerotrema tenuistriatum (Shumard I (r to c) '':\lurchi,_;;onia" sp. undet.. Cine fragment Trepc•,;.pira depres,;.a '? (CCIX). small indi,·iduals (c) Strapart•llu,;. 1 Euomphalus or Schiwstoma., subrugosus? C'\1eek and \\'orthen1 umard) I x I I I I I x ~Or-b1-cu-lo-i-., .£ 1: ~ 0 "' E: " .£ e ~ 3 ----------------1I0x<:: I~ L~ ~ ~ I:x~ ~l ~x"' IJI~ L~ ~ -~ ~ "Productus" (Dictyoclostus) port­lockianus Norwood and Pratte'l -~-·:_:_:~_.:_i~_:u_r:_,,_la____ _ : xx : xx l~:Tt--:x x: ? 1 ? x 8;_a·l_l~_:_:_i:_t._(W_o_rt_h_cn-') :x x x Marginifera splcndens (Norwood and Pratten) var. A 1 1 1 1 1 1 1 11 1 Wellerella osai;ensis (Swallow) n. var. I I x I I l~I I -:W::-:el:;-le_r""""'.el::-Ia_sp:.._...:..•_,_p_ro.:..:b.:..:a..:.b...:.ly~n..:.cw~-----1 I x -1--1 1-1-1 l_ I______ --~W~e=l=le~re=l=la=s=o=.=u=n=d=ct=.===============R~ynchopora illinoisensis (Worthen) ll=~?11. x I II II I 1=1~1 x ll~I== ? ? -::R-h--:yn--:-c-ho--:pc:-:or_a_s_p._u_n.:....,d_et-.--''-----ll_xI xx II tl-11-11-1 II x I 11-11--== Dielasma bovidcns (Morton) ---:S:--p-:-~r-:-'~:-~~-f0-~::-N:-e-o-sp_i_ri-fe_r.,..)_k_a_n_sa_s_e_ns_i_s___:I I I x I 1=1I I I I Ix =-= Spirifer (Ncospirifer) texanus Me"k ~l_x_I_ I_ ~1-Hl2.J_I__ --;:S:--p-:-ir..,..if:-c_r_(_N_e_o~sp..,..i_ri_fc_r"'"-)-t_rii_t_u_s_H_a_l_l__...:.x~~-x_ l~_x x_l-2...!~2__~ ..:..p_I_cal l,1__ Spirifer sp. undet. I I x I x I I I x I I x I x I =~S~q=u=am~~u=la:ri=a~p=e=r=pl=e=xa==(~l\~1c~C~h=e~sn=e=y=)=====~I =x=~~x~~~x~I I I x I x I I I -­ I J _c,...r_u_ri_th_y_r_is....:p_l_an_o_c_o_n_ve_x_a_(_S_h_u_m_a_rc...:I)___:_I_ ~Ix l__l_ l_/__l_x_l~-1---;-,--- Crurithyris sp. undet. r_,_,_I I l=I I I I l_J=~-x _P._u_n_ct_o:-sp'-i_ri_fe_r_ke_n_t..,.uc_k-'y_e_n_si_s_:(...:.S_..:.."'..:..n.::.ar:...:d~)_..:....:.x::_cl..2_12__x_l__l_I x I x l~_I ? --­ ~l 1lHusted a mormoni (Marcou) I x I x I x I I I I /~x J I---­ Stratigraphic and Paleontologic Studies 223 Distribution of species in collections studied from various formations ___________w_i_th_in_ a_r_e_as of investigation-Continued Aviculopecten sp. undet. Dentalium subleve Hall x -i-1 I 1-1 _.::_D..::.en:.:.:t::.a.'..'.:liu:::_1:.:.:n_:s::::p:.:.~u:.:n..=d_.:e:::t..:..--------;---;--~--1 I __j_i ­ _:_P:::.:la.'...'..'.'.gio'.'..'..'.gl'...'...'..'.yp_::.ta!'...:...c...:::.:f.~P.=a-nn-;ul:-:-ist-:-:ria~ta----,-x j ~--_ml !-x I_ - (\ferk and Worthen) Plagioglypta sp. undet. 224 The University of Texas Publication No. 3801 Distribution of species in collections studied from various formations within areas of investigation-Continued Brazos River Valley Colorado River Valley Bellerophon sp. undet. I-??_?___ ? ? Patellost1um montfortianum (i\orwood __L_l l I -- and Pratten) L ----'- Patellostium n. sp.? I I _E_u~p_h_________ ____ -_1 __cm_it_es_ca_r_b_on_a_r_iu_s_(C_o_x.c..·) x-:...l :,__-_-+-=-=====-x_-_,-,_-+-_, Bucanopsis meekiana (Swallow) 1 1-1____2.___1_ Bucanopsis sp. undet. x I 1 1 Pharkidonotus percarinatus? (Conrad) I x 1 _ l_ l_ l----;---1--+--i-­ -P_h_a-rk_i_d_on_0_t_us-tr-ic-L~-i---;--­_a_r-in_a_t1-1s-(S-.-rn-m_a_r_d~)--,-~-l Pharkidonotus sp. undet. I II ~ _ l__ll= I II ,-= "Pleurotomaria" obtusispira Shumard 1 __a_ti_c_op_s_is_?_sp_._u_n_d_c_t.________:__1_ 1x x I j I I ,----,--,­ I rl I ,,---, I---- Pseudozygopfrura sp. undet. x x Meekospira sp. undet. I 111-H--~l-I ---­ Sole--'--niscus---,-----(Macr-ochili-na)cf_. x I ~I--x I '------­ White or cf. S. paludinaeformis (Hall) S. br-evis--L-1 I ---'-Soleniscus (Macrochilina) primigenius l__J I I~I (Conrad) x =­ -=-So-,--ieni•-:---cus_(M:ac_roch-:--ilina-'-----'-)sp_. ___ I2-= und_et.---+-+I L.-l-=x _ I 1 Trachydomia sp. undet. I x I j I l__j -P-la-ly-cer-as-sp-.-un-de-t.------;--x I -,-I ---­ Stratigraphic and Paleontologic Studies 225 Distribution of species in collections studied from various formations within areas of investigation-Continued I Brazos River Valley I Colorado River Valley u'I·~ I0 gI 10 .~ .. 111 g g 1 ·~ ll ~ ~ ·~ ~ :: ·3 ~ I § '-ci -...... .:::: ·~ ­ !~ ,i 1U~:H1l~H1t H~ 0 0 b ~ 1~ ~ 0 ~ u 0 b ~ ~ ~ ~ ~~e-halopoda________________________\ 1__ 1---F'------~'I ~Fl---i---~~ p---___: ___ ~'---1 Pseudorthocpras knoxense (McChesney) x x x 1--P-se-u-do_r_tl-1o_c_e_ra_s_s_e_m_i_no-l-en_s_e_G-i1-·ty---'-'--l--'l-x....:I'---1--i--I~ ---­ "Orthoceras" (Mooreoceras) aff. I j I -1--~~----­ 1I 0 . tuba Girty x 1--,-.0r-th-oee_ra_"-'(-Do-lo-rth-oc-er-as-)-cis-co-en-se_l _J._-xc,--1-1--I x ---­(\filler. Dunbar and Condra) ._"0-rtho-cera_•" _(Eu-loxo-cer-as) --'---gree-nei_l_ l_x1~1-l_l_lll-1--_.-_ ___x1­ ,_(\fillrr. Dunbar and Condra) . ·-·­"Orthoceras" aff. 0. cribriliratum Girtv I I I I j [ __i___J I "Orthoceras" sp. undet. 1 I : -1-1-ji ---;-J-----­ :~~B~r~~~~~~~c~a~~c~:~~cd~er:~~:~~~~~~'.;'~a~l~e~l\~1i~ll~e~r,~~~~~~~~l~~~l·~~x~l:~---l=l-l_l-I I x 1-1 === '--l- Coloceras lira:um G'rty I x I~ I J I I x I Tainoceras monifer Miller, Dunbar I I I _ l_l_I I I I I I l-1_an_d ·-----,---~--~~­ Con_dra---'----­1_\f_e_ta_co_c_e_ra_s_c_o_r_nu_t_u_m_G_ir_t'-y------1'-------x-l.___LI-l_x_I___, __ c____l 1_\f_e_ta_co_c_e_ra_s_c_o_r_nu_t_u_m_c_ar_in_a_t_u_rn_G_ir--'ty'---1'----'l._x_l_ j _j 1-1_1 __,_'-­ \letacoceras cornutum sinuosum Girty l_i~I-_ l+ l_L_J___x_l____f---­ 1_,f_c_ta_co_c_e_ra_s_p'--e-r_el_e.o..ga_n_s_?_G_ir-'ty_ ____I I I I _I_'---~--___ 1 _,_le_ta_co_c_e_ra_s_s_p_._u_n_d_e_t.________lc..____ _:1:__x_ L I I I x I ? 1 1 _Do_ma_to_ce_ra_s_sc_ul_pt_ile_(_G_irt_y)___~_ _ x_x_\1 /_~l=L~x 1 1 j ,_ '-->--­ 1 1I 1ILL Domatoceras sp. undet. 1 1 I 1 1 i--C-yr-to_c_e-ra_s_"_s_p_·1,--:I__.I--;1--­ .. ._u_n_d_e_t.---------:-x-·\-_ -,-CCC'___.___ __ Gastrioceras angulatum Girty J \ j ~'-~\_,___l_x_____1--_ Gastrioceras branneri? Smith I I I cI x 1 1------~'--'-'-_,_____ 1-- Gastrioceras modestum? Bose I j \ x 1-------_'.__-'-C-~ ,·-1------­ 1-G_a_st_ri_oc_e_ra_s_sp_._u_n_d_e_t.__________1 _ .I__x_.1__,_l __\-1----__:____ __c_Ii_st_o_ce_r_as_· _h_ya_t_ti_Sm_it_h______--'-J _ !,_?--:\_-l--'.j-_L_'-_ _.:___,_ 1 __ch_is_to_ce_r_as_h_i_ld_re_t_hi_S_m_i_th jj _ ll __ _ 1. ____ _____c.._xj 1c \_?___,_ 1 1 1 1 1 1 Schistoceras sp. undet. 1 '-D-imorp-ho-cc-r-ast-exa-num-S-mit-h----;--t--x-1-: -r_?Lx 11-1 xx i I ~x1Ii __ _ ~onioloboceras welleri Smith 1 Trilobita: "Griflithides" sp. undet. 1 Phillipsia major Shumard '+~ I ~x Phillipsia sp. undet. ? I ,---I -----­1~=-==-=---------7--f-----'---­ l'ertebrata: I \ I I I Fish remains x x x x 226 The University of Texas Publication No. 3801 REGISTER OF LOCALITIES 7367. Mercury quadrangle. On north side of Herron Bend of Brazos River, about half a mile east of Salem School and thence a quarter of a mile south. Shale in basal part of Graham formation, immediately below Salem School limestone member. 7368. Graham quadrangle. Bass Mountain, 2 miles northeast of South Bend, hill above and 100 feet north of Brazos River. Graham formation, in shales 25 feet above Bunger limestone member, which crops out near water level. 7369, 7369A. Waldrip quadrangle. Locality adequately described in text. Graham formation, fossil zone 4 Ge, 10 to 20 feet below the Gunsight lime­stone member. 7370. Waldrip quadrangle. About 4 miles south of Whon and three-quarters of a mile east of Parks Mountain. To reach the locality from Whon, go south 4 miles, take first turn west, go for three-quarters of a mile, then go through gate and continue about half a mile north and a quarter of a mile west to southeast point of an isolated hill. Wayland shale member of Graham formation. 7440, 7440A. Graham quadrangle. West edge of town of South Bend, from flat between railroad that runs along Clear Fork and road to Throckmorton. Graham formation, fossiliferous zone 20 to 40 feet above Bunger limestone member. 7441. Young County. About 9 miles southeast of Graham on Graham-Finis road, in road cut north of Brushy Mound, which is first hill west of Connor Creek School, outcrops in roadside ditches. Graham formation, fossil zone 16 Gb, marine shale about 40 feet above Home Creek limestone of Plummer and Moore (top member of underlying Caddo Creek formation) . 7442. Graham quadrangle. About 2% miles northwest of Graham, in rail­road cut south of road and across road from a dam on Salt Creek. Graham formation, Wayland shale member, thin No. 9 limestone of post-Bunger cycle No. 9 and associated shale. 7443. Graham quadrangle. Near head of Kickapoo Creek, 100 yards north of point where road crosses creek. Graham formation, No. 9 limestone in post­Bunger cycle No. 9. 7444. Graham quadrangle. About 3 miles south of Graham, near Thedford Tank, on north side of North Tonk Branch, about three-eighths of a mile north­west of point where railroad crosses branch and about one-eighth of a mile northeast of road. Graham formation; the fossiliferous shale zone 40 feet above Bunger limestone member. 7445. Same locality and horizon as 7440. 7446. Graham quadrangle. In west edge of town of South Bend, in breaks about 300 to 400 feet west of main street (highway 67) and 200 feet south of road to Throckmorton. Graham formation; the fossiliferous shale zone 25 to 30 feet above Bunger limestone member. 7447. Graham quadrangle. Locality adequately described in text. Fossil zone 10 Gb of Graham formation. 7448. Graham quadrangle. Cliffs along west side of Salt River in west edge of Graham, north of Graham-South Bend road, one-eighth of a mile north on road to dam, from beds near top of bluffs. Wayland shale member of Graham formation, about horizon of No. 9 post-Bunger cycle limestone. 7449. Waldrip quadrangle. Same locality and horizon as 7370. 7450. Graham quadrangle. About 21,6 miles west of South Bend, Young County, on southeast point of hill, north of Graham Lake, about halfway up. Graham formation, No. 9 limestone of No. 9 post-Bunger cycle. 7451. Graham quadrangle. Same locality and horizon as 7442. 7452. Young County. Same locality and horizon as 7441. 7453. Ivan quadrangle. At side of east-west road that runs along Young­Stephens County line, about half a mile east of Graham-Breckenridge highway, at first escarpment. Graham formation, No. 3 post-Bunger cycle limestone. 7454. Graham quadrangle. Northwestern part of hill about 1 mile northeast of Graham (first hill beyond twin hills in Graham), less than 200 feet south of Chicago, Rock Island & Pacific R~ilway, above oil pit and below a sand­stone. Near base of Wayland shale member of Graham formation. 7455. Waldrip quadrangle. Same locality and horizon as 7369. 7456. Graham quadrangle. About 4 miles northeast of Graham and 1 mile southwest of Rocky Mound School, on southwest side of Rocky Mound, near base of hill, a quarter to half a mile southeast of road from Graham. Graham formation, Wayland shale member, below 9a limestone of No. 9 post-Bunger cycle. 7485. Graham quadrangle. Locality near 7454, but about halfway up west face of hill 150 to 200 feet north of south point of hill, under a conglomerate. Graham formation, near base of Wayland shale member. 7486. Ivan quadrangle. On main road from Eliasville to South Bend, 3.2 miles from Eliasville, on long hill northwest of road, between two bridges. Collection from point where hill is nearest road, up nearly to top of hill and 5 or 6 feet above a sandstone ledge. Graham formation, 9a limestone of No. 9 post-Bunger cycle. Limestone is thin and discontinuous under a conglomerate. 7488. Graham quadrangle. Same locality and horizon as 7367, except that it contains float from Salem School limestone member immediately above. 7489. Graham quadrangl((. Same locality and horizon as 7456. 7490. Graham quadrangle. Herron Bend of Brazos River, on road that passes Salem School; about three-quarters of a mile east frc:m school, thence south and east to a point about a quarter of a mile south of bench mark 1005, shown on topographic map. This point is about 1% miles southeast of school, where road begins to turn southeast away from Herron Bend. Exposures about 5 feet above creek and on creek in field west of road, a little south of northeast point of bend. Caddo Creek formation, Home Creek limestone member of Plummer and Moore. 7491. Graham quadrangle. About 3 miles north and slightly east of South Bend on east side of Sidney ~fountain, downhill east of Wadley oil well, about a qu:rter of a mile north of bench mark 1082, at altitude shown on topographic map as ll80 feet. Graham formation, limestone of No. 5 post-Bunger cycle. 7492. Graham quadrangle. About 214 miles north of South Berni. Southwest point of butte on east side of Kickapoo Creek, about a quarter of a mile west 228 The University of Te:ras Publication No. 3801 of bench mark 1082, at about 1100-foot contour line as shown on topographic map. Graham formation, limestone of No. 5 post-Bunger cycle. 7493. Graham quadrangle. On west side of Kickapoo Creek, about half a mile S. 45 ° W. from 7492. Graham formation, limestone of No. 6 post-Bunger cycle. 7494. Graham quadrangle. About l % miles north of South Bend and six· tenths of a mile north of where Clear Fork joins Brazos River, about one-eighth of a mile north of southwest corner and on west side of a butte, which is the first butte north of river here. On west side of same butte as 7492. Graham formation, a "Campophyllum" bed about 120 feet above Bunger limestone, below horizon of Kickapoo limestone. 7495. Graham quadrangle. About 1 mile west and 1% miles north from South Bend, on hill about half a mile north of Stovall hot-water well on south· west side of Salt Fork of Brazos River, along road shown on topographic map as a temporary road going northwest fr~m bench mark 1036 to bench mark 1116, near point where road crosses 1080-foot contour line shown on map. Graham formation, limestone of No. 6 post-Bunger cycle. 7496. Graham quadrangle. About 3 miles N. 45° W. of South Bend, as measured on map, along ~tream tributary to Salt Fork of Brazos River, about three-eighths of a mile upstream from Salt Fork. This tributary enters Salt Fork at south point of second sharp bend southward, west of point of entrance of Clear Fork. About half a mile east of bench mark 1153, shown on topo­graphic map, on east side of tributary stream, 10 to 12 feet below top of hill. Graham formation, limestone of No. 7 post-Bunger cycle. 7497. Ivan quadrangle. Locality adequately described in text. Graham formation, limestone of No. 3 post-Bunger cycle. 7498. Graham quadrangle. Locality adequately described in text. Graham formation, limestone 9b of No. 9 post-Bunger cycle. 7499. Ivan quadrangle. About l % miles south of South Bend. Top of South Bend l\fountain, which is the first crest south of South Bend that is more than 1200 feet in altitude. Graham formation, limestone of No. 7 post-Bunger cycle. 7500. Stephens County. Locality adequately described in text. Upper lime­stone of Gunsight limestone member of Graham formation. 7501. Graham quadrangle. About half a mile west of McCann bridge over Brazos River, about 1% miles south and 8% miles west from Graham. Thrifty formation, Blach Ranch limestone member. 7502. Breckenridge quadrangle. About 2 miles due south from Gunsight, along "old" road to Eastland. To reach locality go past post office at Gunsight, turn left at first fork, and continue until speedometer shows 2 miles from post office. Lower limestone of Gunsight limestone member of Graham formation. 7504. Breckenridge quadrangle. About l % miles northeast of Crystal Falls, on diagonal road to Eliasville north of Clear Fork of Brazos River. Brecken· ridge limestone member of Thrifty formation. 7505. Mercury quadrangle. Along north bank of Colorado River, about 2% miles east of Winchell, where road comes close to river at first really prominent northward bend east of Winchell, on old "river road." On bank of river within about 10 to 15 feet of water. Graford formation, thin brown limestone in basal member. 7506. Mercury quadrangle. Same locality and member as 7505 but in a zone about 10 feet lower. 7507. Mercury quadrangle. Locality adequately described in text. Adams Branch limestone member of Graford formation. 7508. Mercury quadrangle. Locality adequately described in text. No. 2 limestone (second limestone from base of Winchell member of Graford forma­tion, equivalent to top bed of Drake's Clear Creek limestone). 7509. Mercury quadrangle. About 4 miles east of Whon, on road that crosses Home Creek in Gill ranch, on hill above and south of creek, about one-eighth of a mile south of elevation No. 1403, shown in northwest corner of map of Mercury quadrangle. Caddo Creek formation, Home Creek lime­stone member of Plummer and 1\foore. 7510. Waldrip quadrangle. About 4% miles slightly west of south of Whon, in bed of stream where road from east side of Parks Mountain turns from southward to southeastward, about a quarter of a mile above junction with a northeast-southwest road, about five-eighths of a mile south of point 1518 (see topographic map) on Parks Mountain and about three-eighths of a mile east of Colorado River. Upper limestone of Gunsight limestone member of Graham formation. 7511, 7512. Young County. About 91h miles east of Graham, on a hill about 500 feet north of Connor Creek School and across road from it. This school is on Graham-Finis highway. Locality is near top and on south side of hill, east of the stone fence on the hill. Upper 3 feet of Gonzales limestone member of Graham formation, as exposed here. 7513. Young County. Same locality as 7441, but collection made from a thin yellow limestone below a thick sandstone and above marine shale of fossil zone 17 Gb and below horizon of Gonzales limestone member, exposed on first flat south of road and above roadside ditch. Limestone 50 to 60 feet above horizon of Salem School limestone member of Graham formation. 7514. Young County. Locality adequately described in text. Gonzales lime­ stone member of Graham formation. 7515. Graham quadrangle, About 4 miles S. 20° E. of Graham, as measured on map. Collection from top of road 2 to 3% feet below level of house and barn to which road leads. These buildings are in a saddle north of Graham­ Graford road, 2.3 miles east of place where road to Bunger turns off and 1.8 miles west of place where road to Herron Bend turns off. Graham formation, "dirty yellow" limestone 22 feet below Bung_er limestone member. 7516. Same locality as 7515 but from a zone about 5 or 6 feet higher, exposed on first flat above and west of saddle. 7517. Graham quadrangle. About 6 miles south of Graham, near Bunger. To reach locality from town of Bunger, go south one-third of a mile, turn east and go half a mile to place where a limestone crosses road at first rise. Collection obtained along road and in pasture south of road, from an olive­ brown fine-grained limestone. Bunger limestone member of Graham formation. 230 The University of Texas Publication No. 3801 7518. Same locality as 7517, but collection made from a weathered zone in side ditch north of road. Float but probably from Bunger limestone member of Graham formation and not over 4 feet below it. Could have washed from beds 8 to IO feet above Bunger. 7519. Same locality as 7517, but 500 to 600 feet west .. From roadside ditches and fields on each side of road. Soft brown sandy limestone with red splotches below a red weathering zone. Graham formation, "dirty yellow" limestone about 20 to 25 feet below Bunger limestone member. 7520. Breckenridge quadrangle. On Gage Creek about 11/z miles west of Eliasville. To reach locality go west from bridge at Eliasville on Throckmorton road; at about 11/z miles from Eliasville turn right through wooden gate, pass cemetery, and bear left to Gage Creek as far as a water hole with a spring box. Upstream 100 feet or more east of spring box is a limestone below Ivan. limestone. Thence continue upstream to Ivan limestone. Ivan limestone mem­ber of Thrifty formation. 7521. Young County. About 31/z miles west of McCann Bridge, on Vick ranch, across road south of ranch house, on hill above creek in pasture. To reach locality from a point in road opposite ranch house, go east 2.2 miles to a gate on south side of road that leads to Nash & Windfohr oil pool. Collection from ridge west of oil wells. Belknap limestone member of Harpersville formation. 7522. Graham quadrangle. Locality adequately described in text. Bunger limestone member of Graham formation. 7523. Graham quadrangle. Locality adequately described in text. About 2 feet above base of Bunger limestone member of Graham formation. 7524. Graham quadrangle. Locality adequately described in text. Bunger limestone member of Graham formation. 7525. Graham quadrangle. About 21/z miles (measured on map) west of South Bend, in field 50 to 200 feet north of road on crest of hill, which is about Ph miles due west of Stovall hot-water well. A road turns south about 100 feet south of this locality opposite bench mark 1131, which is shown on topographic map. Graham formation, limestone of No. 7 post-Bunger cycle. 7526. Graham quadrangle. Same locality and horizon as 7450. 7527. Breckenridge quadrangle. About 1.1 miles north of Eliasville. To reach locality from Eliasville cross bridge over Clear Fork, take road to left about a quarter of a mile, turn right (north) where first road comes in, continue north until road makes an almost right angle jog to east and con· tinues up a sandstone and shale hill. Instead of turning, continue on through an open iron rod-floored gate into a drive that goes around hill to a house not visible from road. Collection from limestone at first rise above gate. Thrifty formation, 4-to 6-inch unnamed limestone above Avis sandstone member and below Ivan limestone member. 7533. Breckenridge quadrangle. Same locality as 7527, but collection made from flat on which house stands. Ivan limestone member of Thrifty formation. 7534. Breckenridge quadrangle. Along roadside west of road and along a gully 100 feet west of road that enters Crystal Falls from north. Collection came from a point on road one-third of a mile south of Huffstettle School south of a hill and north of a bridge over a gully. 2\Jyalina-bearing limestone of Harpersville formation. 7535. Breckenridge quadrangle. To reach locality frorn Crystal Falls, go 51;:! miles north, thence 3 miles west, then turn into field and go 1.8 miles south to a hill in pasture. On first bluff on Clear Fork east of mouth of Kings Creek there is a stone fence on hill and also stone fences in pasture. Out­crops near top of hill and east of temporary road in pasture. Saddle Creek limestone member of Harpersville formation. 7536, 7537. Breckenridge quadrangle. Crystal Falls, exposure along Clear Fork of Brazos River, from water level up to 3 feet above water level at a place 50 to 100 feet below a dam, which is about 300 feet below bridge where highway crosses Clear Fork. Breckenridge limestone member of Thrifty formation. 7538. Breckemidge quadrangle. Crystal Falls, north of railroad, about 80 to 100 feet west of road north out of Crystal Falls and about 300 feet south of a pump house on Clear Fork of Brazos River, on south side of first ravine south of pump house. "Cl" limestone bed of maps, in basal part of Harpers­ville formation. 7539. Breckenridge quadrangle. Crystal Falls, across railroad in northern part of town, in field east of tracks in first railroad cut northwest of Crystal Falls crossing, almost due west of pump house for Breckenridge water supply. Exposure in "humps" on a ridge back of pump house and also in beds in railroad cut. Crystal Falls limestone member of Harpersville formation. 7540. Breckenridge quadrangle. Crystal Falls, along railroad northwest of town, second cut northwest of road crossing in north edge of Crystal Falls, opposite a house on same lot as pump station of Magnolia Petroleum Company. Thin limestone and shale on southwest side of railroad. So-called "Upper Crystal Falls limestone," in Harpersville formation. 7540A. Same locality and horizon as 7540 but collection made from shale parting. 7541. Breckenridge quadrangle. Four miles west of Eliasville, to left, beyond west edge of Eliasville oil pool, through cattle guard on short road to Crystal Falls, a quarter of a mile; locality on top of a hill. Crystal Falls limestone member of Harpersville formation. 7542. Same locality as 7541, but collection made in ravine to the north. Breckenridge limestone member of Thrifty formation. 7543. Breckenridge quadrangle. West of Eliasville, on Throckmorton road, 6.9 miles by speedometer; in roadside ditch at head of Wagon Timber Branch. Belknap limestone member of Harpersville formation. 7544. Breckenridge quadrangle. About 7 miles by speedometer west of Eliasville. To reach locality go 51/z miles north of Crystal Falls to place where road turns, thence 700 feet east to place below top of first hill. Thin limestone between a shale and limestone that caps hill and light blue and gray to purplish shale exposed in roadside ditch and field south of road. Saddle Creek limestone member of Harpersville formation. 7545. Same locality and horizon as 7521. 232 The University of Texas Publication No. 3801 7546. Ivan quadrangle. About 9 miles (measured on map) east of South Bend, 4% miles east and 21/i miles south of Bunger, near Ming Bend School. Outcrops in field adjoining school on south and on a flat across a ravine near the school, also along a road through a field south of school and through two gates from main road that passes school, about 500 to 600 feet south of school, in State game preserve. Caddo Creek formation, Home Creek limestone member of Plummer and Moore. 7547. Same locality as 7541, but collection made on sides of a tank 0.3 mile around hill to the west. Exposures about 15 feet above tank, nearly at base of hill. So-called "Upper Crystal Falls limestone," in Harpersville formation. 7548. Same locality and horizon as 7486. 7549. Breckenridge quadrangle. To reach locality go T1h miles west of bridge at Eliasville, turn left through a gate into a pasture, and go southeast to place where Wagon Timber Branch is crossed by a fence. Exposures a few hundred feet upstream. Collection from an 8-to IO-inch limestone about 8 inches above a coal. So-called "Waldrip limestone," in Harpersville formation. 7550. Same locality and horizon as 7442. 7551. Same locality and horizon as 7500. 7552. Same locality and horizon as 7502. 7553. Breckenridge quadrangle. Locality adequately described in text. Upper limestone of Gunsight limestone member of Graham formation. 7554. Throckmorton County. Four miles east of Woodson, in a gully south· east of road forks, at place where road turns south. Camp Colorado limestone member of Pueblo formation. 7555. Throckmorton County. About 3, miles east of Woodson, in stream bed 200 feet south of road and bridge. Collection from bed of stream. Unknown horizon in lower part of Moran formation. 7558. Waldrip quadrangle. About 4 miles south and half a mile west of Rockwood, about 114 miles due south of Chaffin crossing over Colorado River, on Chaffin farm, along banks of a small stream below mines, east of Chaffin house. Chaffin limestone member of Thrifty formation. 7559. Waldrip quadrangle. Same locality as 7369 but near top of hill south of road. Upper limestone of Gunsight limestone member of Graham formation. 7560. Waldrip quadrangle. Locality adequately described in text. Thin brown limestone near base of Graham formation, 8 feet above Plummer and Moore's Home Creek limestone member of Caddo Creek formation. 7561. Same locality and horizon as 7509. 7562. Waldrip quadrangle. Northwestern part of Rockwood, on first gully about 500 feet west of cotton gin. So-called "Waldrip No. 2 limestone," in Harpersville formation. 7563. Waldrip quadrangle. West of northern part of Rockwood, near top of an eastward-facing isolated hill, about 1500 feet westward across a reddish shale valley from cotton gin. So-called "Waldrip No. 3 limestone," in Harpers­ ville formation. 7564. Waldrip quadrangle. Ridge west of Rockwood. To reach locality turn west into field from highway that goes south into town, immediately south of bridge in north edge of town, continue on farm roads, keeping near but north and west of "breaks," 1 mile westward to a gate, thence to ridge north of gate and a few hundred feet west. Saddle Creek limestone member of Harpersville formation. 7565. Waldrip quadrangle. About 2 miles south and 4 miles west of Rock­wood, about 1% miles west of highway bridge southwest of Rockwood over Bull Creek. To reach locality from this bridge, go we~t from south side of bridge, follow road through two gates-one gate at 1 mile from turn (bridge and road) and the next due west of the first, at 1.4 miles from bridge. Hill left of second gate overlooks Colorado River. Collection made at top of cliff that borders a draw, a few hundred feet east of point of this hill and a gravel flat in river visible from it. Saddle Creek limestone member of Harpersville formation. 7566. Waldrip quadrangle. From locality 7565, go westward, passing through a gate at point 1 % miles west of 7565, thence west a few hundred feet farther, turn right, and continue up a ravine for about 1000 feet to hill west of this ravine, 12 feet below top of escarpment. Thin limestone near base of Pueblo formation, 20 feet above Saddle Creek limestone member of Harpersville formation. 7567. Waldrip quadrangle. Along Colorado River, 4 miles south and 7 miles west of Rockwood (measured on map), on point above river about 0.9 mile southeast of conspicuous round hill where the first big draw east of the round hill cuts into bluff, near west margin of Waldrip quadrangle. Pueblo formation, in Drake's bed No. 13 ("limestone with yellow chert"), the Stockwether lime­stone member of Plummer and Moore. 7568. Waldrip quadrangle. Rockwood; flat around barn and between house and barn of first house south and east of south end of bridge on highway on north edge of Rockwood. So-called "Waldrip limestone No. l," in Harpersville formation. 7569. Waldrip quadrangle. About 2.4 miles east and 0.2 mile south of Rock­wood (measured on map), on west bank of Camp Creek, about a quarter of a mile north of road from Rockwood to Whon, across a draw. Bench marks 1459 and 1422 (see topographic map) are on this road. Chaffin limestone member of Thrifty formation. 7570. Same locality as 7569, bnt collection made about 50 feet north and at about 10 to 12 feet lower in altitude, the bed being only about 4 feet above stream and above a red shale, which is exposed nearly to creek bed on west side of Camp Creek. Thin limestone 10 feet below Chaffin limestone member of Thrifty formation. 7571. Waldrip quadrangle. About 2% miles east and a quarter of a mile south of Rockwood, on same road as 7569 but farther cast, at a point where this road turns south instead of crossing Camp Creek. Exposure in bed of Camp Creek and on an abandoned road on east side of Camp Creek in line with road. Speck ]\fountain limestone member of Thrifty formation. 234 The University of Texas Publication No. 3801 7572. Waldrip quadrangle. About 31/i, miles south and half a mile east of Rockwood (measured on map), about a quarter of a mile west of Parks Moun­tain, at a point where road around west side of Parks Mountain to Colorado River crosses a ravine shown on map of Waldrip quadrangle as first ravine west of Parks l\fountain and north of river. Road goes through a sharply constricted place where it crosses this ravine. Yellow shale exposed to left (east?) at crossing. The Bellerophon limestone caps hill. Bellerophon lime­stone, in Thrifty formation. 7573. Coleman County. About 6.2 miles southwest of Gouldbusk, where road crosses escarpment of Coleman Junction limestone. To reach locality from Gouldbusk, go 0.3 mile south, 0.7 mile west, 0.5 mile south, 2 miles west, and about 2.7 miles south. Collection from both sides of road in big valley to the south below escarpment. Coleman Junction limestone member of Putnam formation. 7574. Coleman County. About 7% miles by speedometer. southwest of Gouldbusk. To reach locality from locality 7573, go south about 1 mile, east half a mile to place where Panther Creek crosses an east-west road, up Panther Creek to point near south end of a hill, west of first house east of Panther Creek. Collection obtained less than 1 foot above base of a small gully east of hill, between sheep pen and house. Shale 8 feet above Horse Creek limestone member of Moran formation. 7575. Same locality as 7574 but farther down same gully, due south of south end of hill. This gully is first gully south of south end of hill. Thin limestone about 5 feet above top of Horse Creek limestone member of Moran formation. 7576. Same locality as 7574, but collection made from blue limestone about halfway up hill, on east and southeast side. Limestone in Moran formation between Horse Creek and Sedwick limestone members. 7577. Same locality as 7574, but collection made in public road, which goes in front of house, and in field south of road, on first bench above and east of point where road crosses Panther Creek. Horse Creek limestone member of Moran formation. 7578. Waldrip quadrangle. Locality adequately described in text. Caddo Creek formation, in Home Creek limestone member of Plummer and Moore. 7579. Waldrip quadrangle. Isolated hill half a mile north of Colorado River and a quarter of a mile east of west line of quadrangle. Limestone 60 feet below Camp Colorado limestone member of Pueblo formation. 7580. Coleman County. Three and one-fourth miles east and three-quarters of a mile north of Whon (measured on map), on west side of Mukewater Creek about three-eighths of a mile above its junction with Home Creek, first escarpment west of creek and below a sandstone. Brad formation, in Ranger limestone member of Plummer and :Moore. 7581. Same locality as 7580 but higher on hill and above the sandstone. Caddo Creek formation, in Home Creek limestone member of Plummer and Moore. 7582. Coleman County. About 8 miles southwest of Couldlrn,-k, about 114 miles westward and across a hill from locality 7577. Limestone 77 feet below Coleman Junction limestone member of Putnam formation. 7583. Nearly same locality as 7582. Coleman Junction limestone member of Putnam formation. 7584. Coleman County. About 7.1 miles southwest of Gouldbusk. From locality 7577, go west across Panther Creek and north into gate about 0.2 mile west of Panther Creek crossing; continue about half a mile to outcrop of Sedwick limestone on west side of Panther Creek. Sedwick limestone member of l\foran formation. 7585. Coleman County. Four and one-half miles southeast of Gouldbusk, on Sam Gray's ranch. Camp Colorado limestone member of Pueblo formation. 7586. Same locality and horizon as 7367. 7587. Same locality and horizon as 7440, but collection made on flats on both sides of Throckmorton road. 7588, 7589. Same locality and horizon as 7368. 7590. Same locality as 7368, but collection made from shales 60 to 80 feet above Bunger limestone member of Graham formation. 7591. Same locality and horizon as 7441. 7592. Breckenridge quadrangle. Two miles south of I van, on hill west of paved highway. Ivan limestone member of Thrifty formation. 7593. Breckenridge quadrangle. Wagon Timber Branch, Donnell ranch, about 7 miles west of Eliasville. So-called "Upper Crystal Falls limestone," in Harpers­ ville formation. 7594. Graham quadrangle. About 7 miles southwest of Graham and 3 miles northwest of South Bend, near mouth of a small ravine, half a mile east of Medlin ranch house. Graham formation, Wayland shale member, at about horizon of 9a limestone of No. 9 post-Bunger cycle. 7595. Same locality and horizon as 7448. 7596. Same locality and horizon as 7543. 7597. Same locality as 7368, but collection made from shales above and within 2 feet of Bunger limestone member of Graham formation. 7598. Graham quadrangle. Two miles west of Stovall hot-water well, which is near South Bend; base of bluff near mouth and on west side of a sma11 unnamed creek that flows northward into Brazos River about l 1h miles south­ west of Medlin ranch house. Graham formation, Wayland shale member near horizon of 9a limestone of No. 9 post-Bunger cycle. ADDENDA This paper was completed for publication before the compre­hensive monograph on the cephalopods of the Carboniferous and Permian of Texas (The University of Texas Bulletin 3701) by Plummer and Scott was published. Consequently, most of the cephalopod names, as well as the names of many other fossils listed herein, follow the usage in· the earlier report by Plummer and Moore (The University of Texas Bulletin 2132). The names which would have been used had Plummer and Scott's treatise appeared sooner may be determined by an inspection of that paper. NOTES ON THE RANGES OF FUSliLINIDAE IN THE CISCO GROUP (RESTRICTED) OF THE BRAZOS RIVER REGION, NORTH-CENTRAL TEXAS LLOYD G. HENBEST1 INTRODUCTION The following brief account of the fusulinid record in north­central Texas is confined mainly to species of Triticites in the Cisco group (restricted) of the Brazos RiYer region. On Brazos River no fusulinids were found higher than the Belknap limestone member of the Harpersville formation. To complete the section, samples are included from the Pueblo formation of the Colorado River area. The Cisco group (restricted) lies near the middle of the Triticites zone. This zone, in broad terms, occupies the upper one-third of the Pennsylvanian and extends into the lower part of the Pseudoschwagerina. zone, now generally considered as of lov,,·er Permian age. Cisco time, however, included the period of greatest expansion of genus Triticites, and as a consequence the Cisco con­tains the best examples of their rapid evolution, abundance of indi­viduals, and wide distribution-the most essential qualities of good guide fossils except in oil geology, where size and recoverability in small samples are also important. From the Brazos and Colorado River regions Mr. Lee and mem­ bers of his party collected over 280 samples of Fusulinidae. The collections represent in considerable detail the standard localities and known occurrences of the different members of the section, as well as a large number of the problematical or unidentifiable horizons that were encountered in field work. The small amount of time and assistance available permitted only the preparation of that part of the collections which was the most closely con­ nected with the stratigraphic problems. AccordinglY, the study of collections of known position in the section was reduced to the bare essentials of erectinf: a stamlard and is not exha11sti1.'e. It was necessary to spend practically all the time on the Brazos Ri\'er collections. For this reason it js to be expected that future studies ll' ni•cd States GC'ological Surn·,-. may alter the ranges as indicated on the accompanying chart, Plate XI. Though incomplete, the record that was worked out for a local standard is interesting and useful. The ranges of different species are so distributed that an average complement of fusulinids ap­pears to be sufficient for rather close correlation in most positions within the area. This apparent situation needs to be checked against the record in the Colorado River valley and considered critically with the possibility in mind that perhaps ecology may be a stronger influence than is recognized in the vertical distribution of f usulinid species. It seemed worth while to present a record of the Brazos River succession as it now stands, as an aid to further work. The iden­tifications are intended to be conservative, in order that the list may be used with more than the usual confidence accorded to routine faunal lists. To promote further accuracy and confidence, "Notes on Species" are included to qualify certain of the identifications appearing on the chart. This will enable other students of the group to compare the list with the results of their own studies. Several new or undescribed forms have been discovered, but as it is inappropriate to include here the writer's descriptions of these new forms, they have been listed as related to ("aff.") known species wherever it seemed possible by so doing to convey an accurate notion of their character. Certain forms, however, are so distinct that they cannot be identified as relatives of known species without inviting misunderstanding. As indicated by the distribution of the fusulinids, only the upper part of the Missouri group is the age equivalent of the Cisco. Species of the lower part of the Missouri group are omitted from the chart, as they do not occur in the Cisco. The stratigraphic positions of the collections from the Brazos River area shown on the chart are those described in other papers in this volume. Specific data on the collections are listed by number at the end of this paper. NOTES ON SPECIES The following notes on the species are included only for strati­graphic information. The temporary and informal designations of species or varieties by letters of the alphabet have been purposely devised to avoid the complications that arise from the use of The University of Texas Publication 3801 Plate XI TRITICITES Z 0 NE lN NEBRASKA(/>.) (d) Uncertainty of the specific identification. (b) Distribution of fusulinids based on Dunbar and Condra, Nebraska Geo!. Surv., Bull. 2, 2d series, (e) The age of the bed is more or less uncertain. 1927. Stratigraphic names. from chart by Condra, Moore, and Dunbar in Dunbar and Condra, Nebraska (f) Two species of Triticites, one of which reaembles T. acutus. Geo!. Surv., Bull. 5, 2d series, 1932. (g) Colorado River region. (c) The Pennsylvanian-Permian boundary is now located by Kansas Geological Survey (1935) at the top of the Brownsville limestone of Condra and others which overlies the McKissick Grove shale of Nebraska. ' No fusulinids were collected from the Moran formation. This formation, which lies below the Putnam at the base of the Permian, has been omitted from the table. Distribution of Fusulinidae in the Cisco group (restricted) of the Brazos River region, Texas, and in the Missouri group of Nebraska and Kansas. manuscript names. Accordingly the writer's manuscript names will be withheld until the descriptions are published. TRITICITES BEEDE! Dunbar and Condra, 1927 Triticites beedei Dunbar and Condra, Nebraska Geol. Survey Bnll. 2, 2d ser., pp. 96-98, pl. 5, figs. 1, 2; pl. 6, figs. 7-10, 1927. [Not T. becdei in White, Univ. Texas Bull. 3211, pl. 1, figs. 16 (?), 17, 18a-e; pl. 2, figs. 7-9, 1932.] ?Triticites consubrinus Galloway and Ryniker U\IS.), in White, llniv. Texas Bull. 3211, p. 41, pl. 2, figs. 16-18, 1932. Triticites plwmneri Dunbar and Condra var.?, in White, Univ. Texas Bull. 3211, rP· 65--67, pl. 6, figs. 7-9, 1932. This species is well represented in the Texas region in typical form. Specimens from the post-Bunger cycle No. 9a limestone are so exactly similar to those illustrated by Dunbar and Condra that they might be mistaken for specimens in the same collection. At this next limestone below (post-Bunger cycle No. 9) the species appears in very slightly less typical form and is a member of the triad (T. beedei, T. nworei, and T. plummeri along with their variants) that characterize that zone. In the post-Bunger cycle No. 9b, T. beedei is a very minor element in the fauna. It is probably most abundant in the No. 9a zone. Earlier forms and variants of this species may easily be confused with T. culloniensis Dunbar and Condra. TRITICITES (sp. A) aff. ( ?) T. BEEDEI Dunbar and Condra, 1927 This form was found in post-Bunger cycle No. 9b limestone. It has several features in common with T. beedei and may be related to that species, but it is slightly less ventricose and less closely enrolled. The walls appear thinner. It might as reasonably be considered a variety of T. ventricosus. TRITICITES CONSOBRINUS Galloway and Ryniker (MS.) in White, 1932 Triticitcs consobrinus Galloway and Ryniker (:\IS.), in White, llniv. Texas Bull. 3211, p. 41, pl. 2, figs. 16-18, 1932. The specimens illustrated by White seem so much like typical T. beedei from the middle limestone of the Wayland shale mem­ber that the name T. consobrinus is not used in this list. TRITICITES CULLOMENSIS Dunbar and Condra, 1927 In the collections that this author has examined from the north­central Texas area no certain occurrences of T. cullomensis have 240 The University of Texas Publication No. 3801 been discovered. At rnrious horizons in the middle and upper parts of the Graham a few specimens resembling T. culloniensis have been seen, but most of them may reasonably be considered an immature stage of one of the associated f onns. For these reasons and owing to a certain degree of uncertainty about the distinctness of the species, the writer has been chary about recognizing it, and wherever listed its identification is questioned. TRITICITES MOOREI Dunbar and Condra, 1927 Triticites moorei Dunbar and Condra, Nebraska Geol. Survey Bull. 2, Zd ser., pp. 99-101, pl. 9, fig. 4; pl. 11, figs. 1-5, 1927. Triticites moorei Dunbar and Condra, in "\\>11ite, Univ. Texas Bull. 3211, pp. 57-59, pl. 5, figs. 1-9, 1932. In the original description of this species no thin sections were figured. White, howeYer, has ably supplied the needed figures based on topotypes. In its typical form the present writer has found the species only in the post-Bunger cycle No. 9 limestone. T. moorei is easily recognized by its small size and abrupt expansion in the second or third volution. By its great numbers it may be consid­ered the most prominent member of the Triticites beedei·moorei­plu m meri triad. TRITICITES (sp. B) aff. T. MOOREI Dunbar and Condra, 1927 This form is larger than typical T. 1noorei and expands slightly less abruptly in the second or third volution. Owing to difficulty in distinguishing juvenile or dwarfed T. secalicus from this form, it is not possible to say with complete assurance that this is a variety of T. moorei. The range is likewise in doubt. A similar and possibly identical form was observed in the Salem School lime­stone. The definitely known range is the same as that of T. moorei. TRITICITES PLUMMERI Dunbar and Condra, 1927 Triticites plummeri Dunbar and Condra, Nebraska Geol. Survey Bull. 2, 2d ser., pp. 98-99, pl. 6, figs. 1-6, 1927. Triticites plummeri Dunbar and Condra, in White, Univ. Texas Bull. 3211, pp. 63-65, pl. 6, figs. 1-6; pl. 9, figs. 1-3; pl. 10, figs. 1-4, 1932. ?Triticites beedei Dunbar and Condra var.?, in White, Univ. Texas Bull. 3211, pp. 36-38, pl. 2, figs. 7-9, 1932. This unique species is abundant in the lower and middle parts of the Wayland shale member and may (according to collection 6-1-i) extend through the Thrifty formation. So far, observations seem to indicate that the most typical form is restricted to the Tn'.ticites species beedei-nworei-plummeri zone, as the Thrifty speci­mens generally are less compactly enrolled or in other varieties are very large. Occurrence in the Home Creek limestone member should be looked for, as the writer has encountered some evidence, of very uncertain value, which suggests that lower range. TRITICITES (sp. C) aff. T. PLUMMER! Dunbar and Condra, 1927 ?Triticites becdei Dunbar and Condra, in White, Univ. Texas Bull. 3211, pp. 34-36, pl. 1, figs. 16-18, 1927. This variant is obviously closely related to T. plumrneri but dif­fers mainly in being ventricosely fusiform instead of spherical and extremely inflated. Its proportions and form are rather similar to those of T. beedei, from which, however, it is easily distinguished by its deeply plicated and basally fused, massive septa and thick keriotheca, which are characteristic of T. plummeri. Specimens of this general description are most common in the upper part of the Graham formation and possibly in the lower part of the Thrifty formation, but a few have been observed in the lower Graham. TRITICITES (sp. D) aff. T. PLUMMER! Dunbar and Condra, 1927 Another variant of T. plummeri is prominent in the upper part of the Wayland shale member. This form is considerably larger than typical T. plummeri and is proportionately less closely coiled. Definite evidence of the upward limits of its range has not yet been worked out. TRITICITES SECALICUS (Say), 1823 Triticites secalicus (Say), in Dunbar and Condra, Nebraska Geol. Survey Bull. 2, 2d ser., pp. 104---108, pl. 7, figs. 1-7; pl. 8, fig. 6; pl. 11, fig. 7, 1927. A generalized, extensively distributed species such a T. secalicus easily becomes a taxonomic catch-all. The range of variation is so great that it is a difficult form to work with in attempts at precise taxonomy and age determination. The author has used as the standard for identification Plate 7, figures 2, 3, and 5, of Dunbar and Condra, which seem to represent the typical form of the species. TRITICITES SECALICUS Dunbar and Condra, 1927 var. ORYZIFORMIS Newell, 1934 This variety appears to be distinguishable in the Brazos River succession, although the identifications are not entirely clear. TRITICITES VENTRICOSUS (Meek and Hayden) The specimens of T. ventricosus from collection 654 are more like those described by Dunbar and Condra from the Hughes Creek shale of Condra in the Kansas-Nebraska region than the higher form of the species. The range of this species (not including the lower, supposed prototypes) extends from the top of the Pennsyl­vanian into lower Permian. Collection 654, however, is older than the Hughes Creek shale of Condra and probably belongs near the lower limits of the T. ventricosus range. TRITICITES (sp. H) Species H is new and is distinct from T. secalicus, with which it may perhaps have been identified in the past. The outstanding characteristics of this form are its slender, distinctly ellipsoidal shape, small number of septa, relatively slight septal plication throughout the central region, and very slight amount of epitheca. The chambers are so wide and so closely meridional in trend that many of the axial sections intersect very few septa in the central region. TRITICITES (sp. I) Near the middle of the range covered by species . H described above is a ventricosely ellipsoidal species that differs from form H by its shorter and thicker shape and greater number of volutions. At the present state of study species I seems to be distinct from Triticitcs secalicus oryziformis Newell. TRITICITES (sp. J) This large species is similar in shape and size to T. tumidus Skinner but has a massive wall structure somewhat mor~ like that of T. plummeri. Even though epitheca is extensively deposited, the structure remains typically Triticites-Iike. GROUP OF SPECIES N TO P In this category stands a group of three or possibly four species. They extend from the upper part of the Graham formation into the lower Permian. They are characterized by very deeply and closely plicated septa, extensive epitheca, and numerous, rather compactly enrolled volutions. The keriotheca is generally obscured, more or less, by extensive epitheca and generally is composed of rather short, wide alveoli and thin alveolar walls. A description of these forms has been begun. Species N.-One of the most distinct members of the group is a fusiform species in post-Bunger cycle No. 9a limestone. This species is associated with T. beedei and T. plummeri. It is very easily distinguished by its W edekindellina-like appearance, with the addition of deep and closely spaced septal plications. Its known range is restricted to the post-Bunger cycle No. 9a lime­stone, but according to collection 675 it may range into the No. 9b zone as well. Species 0.-This species is very large and spherically inflated. In form and appearance it resembles T. tumidus Skinner. Species P.--Though it belongs to the same group as species N and 0, this form is smaller and less ventricose than species 0. SCHWAGERINA sp. In the Coleman Junction limestone (at station 664, Colorado River region) occurs a species of Schwagerina Moller emend. Dunbar and Skinner which is probably not identifiable with S. emaciata. This writer's specimens are sufficiently well preserved to exhibit the generic characters with assurance. This genus belongs to the Pseudoschwagerina zone and accordingly indicates Permian age in the same measure that Pseudoschwagerina does. IDENTIFICATION OF FUSULINID FAUNAS BY EXTERNAL FEATURES Even though a person should be chary about identifying Triti­cit<;s, and in fact most fusulinids, by their external features, an exception exists in the assemblage composed of T. beedei, T. moorei, and T. plummeri. Wherever these three are present, identification can be made with reasonable assurance of accuracy. Identification by external appearance of other assemblages of Thrifty or high Graham Triticites which included T. plummeri is probably less safe. REGISTER OF LOCALITIES 600. (W. Lee No. 1.) Young County, 71~ miles southeast of Graham, north bank of Brazos River, opposite and northeast of Herron Bend, base of steep bluff below road. Home Creek limestone (top member of Caddo Creek forma­tion, of Canyon group). 601. (W. Lee No. 2.) Young County, 7% miles southeast of Graham, near base of steep bluff below road, northeast of Herron Bend of Brazos River. Shale below thin yellow limestone overriding channel deposit (Salem School limestone). 603. (W. Lee No. 4.) Young County, 7% miles southeast of Graham on Finis road, in road cut north of Brushy '.\found, in R. J. Kelly survey, abstract 1813. Limy iron-stained bed about 4 inches thick and about 40 to 45 feet above Home Creek limestone. 604. (W. Lee No. 5.) Young County, 8 miles south-southeast of Graham, on top of high bluff on southeast side of Salem Bend of Brazos River. Shale break in thick section of Gonzales limestone just above 10-foot massive limy sandstone. 605. (W. Lee No. 6.) Young County, 3% miles south of Graham, on top of bluff above north bank of Brazos River, one-fourth mile south of Wichita Falls & Southern Railroad, midway between mouth of Tonk Creek and mouth of Salt Creek. Just below lower bed of Bunger limestone. 606. (W. Lee No. 7.) Stephens County, 10% miles south-southwest of Graham and 3 miles south of South Bend, just south of Young-Stephens County line and 0.6 mile east of Graham-Breckenridge highway, on east side of Duff Branch, on road near base of escarpment. 1ust under post-Bunger cycle No. 3 limestone, an impure limestone about 100 feet above the Bunger limestone. 609. l W. Lee No. 10.) Stephens County, 5 miles southwest of South Bend, where road along county line crosses Peveler Creek. Campophyllwn and Syringopora zones. Believed to be same bed as No. 8 (6 feet below post-Bunger cycle No. 3 limestone). 611. CW. Lee No. 12.) Young County, 3 miles northeast of South Bend, at top of hill nortlrnest of Breckenridge-Graham highway, on Sidney 1\fountain about one-half mile north of highway bridge over Brazos River. Near base of impure limestone about 135 feet above Bunger limestone. Post-Bunger cycle No. 5 limestone. 613. l W. Lee l\o. H.) Young County, 2% miles northeast of South Bend, 1 mile northwest of Graham-Breckenridge highway bridge over Brazos River, at south end of butte between forks of Kickapoo Creek. Collected from an ant hill. Equirnlent to stations 611 and 612. Post-Bunger cycle No. 5 limestone .. 614. (W-. Lee 0o. 15. ) Young County, 21,~ miles north of South Bend, on west side of Kickapoo Creek one-fourth mile west of station 613, 0.6 mile south of secondary road crossing head of Kickapoo Creek. Post-Bunger cycle No. 6 limestone. 135 feet above Bunger limestone. 618. l\\'. Lee :\o. 19.) Young County, 3% miles west-northwest of South Bend, one-fourth mile northwest of highway west of Stovall hot-water well, one-fourth mile south of Salt Fork of Brazos River. in small drain aboYe sand­stone bluff. Post-Bunger cycle No. 7 limestone, about 165 feet above Bunger limestone. 619. (W. Lee No. 20.) Young County, 31~ miles west-northwest of South Bend, on shoulder on east side of mouth of small creek entering Salt Fork of Brazos Riwr from south, 1 1,~ miles slightly west of south of l\Iedlin ranch house and one-half mile southwest of Salt Fork of Brazos River. l\lidJle of three beds equivalent to post-Bunger cycle No. 7 limestone. 619:\. CW. Lee No. 21.) Same locality as 619. Shale below lower of three beds equivalent to post-Bunger cycle No. 7 limestone. Collection washed from shale. 625. (W. Lee No. 26.) Young County, three-fourths mile northwest of court­house at Graham. on west side of Salt Creek below dam. about 80 feet ahove creek (Cummins' locality). Post-Bunger cycle No. 9, No. 9 limestone (in Way. land shale member). 628. (\V. Lee No. 29.) Young County, 1 1~ miles west-southwest of Tonk Valley School, in road ditch about 150 yards south of Lindsey-Seddon well. Post-Bunger cycle No. 9, No. 9 limestone (in Wayland shale member ) . 629. hale: 116 Ho~ne Cre.o>k limestone : 115 Moran formation: Sl. 130-137 post-Hung.o>r cycles: 29. 30, 32, 33, 36, 40. 45. 50. 51. 52. 72 Pueblo formation: 71. 75. 132-123 Putnam formation: S3, 137 Ranger limestone : 112, 116 Rkkt>r sandstont> : 98 Salem School limestone: 17 Santa Anna Branch shale: 136 Strawn gruup: 9S. 99 Thrifty formation: 52. 5S. 121. 122, 124 Waldrip bed: 125-129. 12~)-131 'Watts Creek shale: 136 Wayland shalt>: 50. 52, 121 Winchell member: 104, 106. 112 Sedwick limestone: 79-:'2, 92, 135, 136, 137. 151, 216 fossils from: 217 fossils from limestone below: 217 Selb.rds. E. H.: 218 sept:uia : 65 shale 60 to SO feet above Bunger lime­ stone, fossils from : 172 Shumard. B. F.: 219 Smith. J. P.: 181 Speck Mountain bed: 91 Speck Mountain clav: 122. 123. 124 Speck Mountain limestone: 122, 124-125, 126. 200 fossils from : 198 Staff limestone: 103 Sto~kwether limestone: 78, 'i9, 132, 134, 213 f05sils from: 214 Strawn group: 91-94, 144 section of: 98. 99 summary of formations: 84 Syringopora limestone: 157 table showing distribution of species: 179, 220-225 thickness of formations: 84, 13S, 140 thickness of formations: S4, 138, 140 Thrifty formation: 11. 54-61, 122-128, 139. 1-51. 194-202. 211, 212. 240, 241 Brazos River valley, fossils from: 149­ 197 corrdation of members of: 200 faunal means of differentiating from adjacent formations: 201 fossil zones in Brazos River '-alley: 194 fossil zones in Colorado River valley: 19:' fossils from : 194-202 Thrifty formation, continued outside correlation of: 201 section of: 52, 5S, l::n, 122, 124 thickness of: 84. 13S. 140 Trickham shale: 120. 183, 193 fossils from: 1:36-1SS Triticites: 237 beedei: 239 consobrinus: 239 cullomensis : 239 moorei: 240 plummeri : 240 secalicus: 241 secalicus var. oryziformis: 242 species A: 239 species B : 240 species C : 241 species D: 241 species H to P: 242-243 ventricosus: 242 l:ddcnitcs zone: 194 unnamed limestone. fossils from: 194 "Upper Crystal Falls limestone": 65-70, ';-!. 202 fossils from: 203-204 Yirgil series: 193. 194 'Wabaunsee group: 201. 202. 212. 215 Waldrip limestones: 148. 202, 210, 211 fossils from: 204-205. 208-209 section of: 128-12\l. 129-131 Watts Creek shale: 135 section of: 136 Wayland shale : 12. 24, 45-53, 85, 88, 119. 120-121. 139, 151, 160, 176, 183, 1ro. 191. 192. 193. 19S, 239, 2rn. 241 Brazos River valley, fauna] character­istics: l:Sl comparison of faunas with other z.:>nes in Graham formation: 181­l<;·J fossils f~m: 1iS. 179-180, 180-188 section of: 50. 52. 121 Wells. Lloyd E.: 7. 15, S9, 139 V.'ewoka fauna: 193 formation : 155 White. M. P.: 239, 240 Wichita group: 79-84. 134-137, 149, 151 thickness of: 84, 138, 140 Williams, James Steele: 'i, 148, 153, 195 Winchell member : 9, 91, 9i, 104, 105­107' 112, 150 fossils from: 154 section of: 104, 106, 112 Yockstick, F. F.: i, 149, 153, 1~6. 214, 217, 21$, 219