933-4623-520-4m University of Texas Bulletin No. 1849: September l, 1918 On the Underground Position of the Ellenburger Formation in North Central Texas With a Preliminary Contour Map . BY E. H. SELLARDS Bureau of Economic Geology and Technology Division of Economic Geology J. A. Udden, Director of the Bureau and Head of the Division PUBLISHED BY THE UNIVERSITY SIX TIMES A MONTH, AND ENTERED AS SECOND-CLASS MATTER AT THE POSTOFFICE AT AUSTIN, TEXAS. UNDER THE ACT OF AUGUST 24, 1912 The benefits of education and of useful knowledge, generally diffused through a community, are eHential to the preservation of a free govern­ment. S.am Houston Cultivated mind ia the guardian genius of democracy....• It is the only dictator that freemen acknowl­edge and the only security that free­men desire. Mirabeau B. Lamar CONTENTS PAGE Introduction . . ...................................·. . . . . . . 5 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Previous publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Limitations on the data now available. . . . . . . . . . . . . . . . . . . . . . . 7 Irregularities in the top surface of the Ellenburger produced by erosion. . . • . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Explanation of Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Regional structure in North~Central Texas as indicated by the Ellenburger Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Disturbed Area between the Bend Arch and the Balcones Fault Zone .................... .. ....................... 11 Condition& in North Texas.......... ........ . . . ............ 12 Available Data .. ........... . . . ... .. .......... . ...... . .... 13 List of Wells by counties.................................. . 14 Summary by counties .... . .... .... .......... .. ... .. .. . .. . . 23 Brown County . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Callahan County .................... . ... .... .. . ....... 23 Coleman Cou:::i.ty .... . . . .... : . .. .. . ... .................. 24 Comanche County .. . ...... . ......................... . . 24 Coryell County . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Eastland County . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Erath County . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . 26 Hood County ................. , ........·· . . . . . . . . . . . . . . 26 Lampasas County . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 McCulloch County . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Mills County ............. .. ..... .... .........·. . . . . . . . . 28 Palo Pinto Cou:::i.ty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Runnels County ..................... . ...... . .......... 28 San Saba County . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Stevens County . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Young County .............. ·. . . . . . . . . . . . . . . . . . . . . . . . . . 29 Index. ................ . .... . .. . ......................... .. 31 Map A Preliminary contour map of the .Ellenburger formation. . . . . . . 32 ON THE UNDERGROUND POSITION OF THE ELLEN­ BURGER FORMATION IN NORTH CENTRAL TEXAS WITH A PRELIMINARY CONTOUR MAP BY E. H. SELLARDS1 The Ellenburger limestone, approximating, when fully de­veloped, a thousand feet in thickness, is exposed at the sur­face in the Central Mineral Region of Texas, and from this belt of surface exposures dips beneath later formations. To the north from the Central Mineral Region, the position of the formation is more or less well-known from drilling rec­ords as far as Young and Palo Pinto counties, beyond which it passes to depths not yet reached in drilling. However, approaching the north State line it is again brought suffi­ciently near to the surface to be reached by a few wells in the structurally high area adjacent to the Red River. With tl;le exception of the Vestal well in Callahan County, the formation itself is not known to be productive of either oil or gas in commercial quantities. However, its relation to the producing formations is such that the accurate or ap­proximate determination of its position below the surface becomes a matter of much importance. As a rule, test wells for oil in north-central Texas are not drilled deeper than to the Ellenburger limestone. To have a knowledge of the ap­proximate depth at which this formation will be encoun­tered is, therefore, important in planning a test well. In addition, the structural conditions in the Ellenburger are, with little doubt, more or less reflected in the overlying pe­troleum-bearing formations. Hence the structures in the Ellenburger suggest the probability of similar structures in the later formations. This paper relates to the position of the Ellenburger limestone below the surface in north-central Texas as indicated by well records. 'Paper read in abstract before the Dallas meeting of the Ameri­can Association of Petroleum Geologists, March, 1920. Published by consent of the Association. Revised and submitted for publication April, 1920. Issued July, 1920. ACKNOWLEDGMENTS To the Director of the Bureau of Economic Geology of the University of Texas the writer is indebted not only for the opportunity of working on this problem, but also for access to the many data on this problem that have accumulated in the records and files of the Bureau. For data more recently obtained the writer is under obligation to all the large oil­producing companies operating in north-central Texas, and in particular, to the geological and scouting departments of these companies, and to drillers and others. The logs of wells have been obtained either directly or indirectly from the companies testing for oil. The surface elevations at the wells where known by instrumental surveys are to be cred­ited entirely to the operating oil companies. Where eleva­tions based on instrumental surveys are not available, the elevations of the wells have been estimated from the topo­graphic maps of the United States Geological Survey. The samples of cuttings, like the logs, have accumulated in the Bureau collections at different times and from various sources. Many of them have come to the Bureau from ge­ologists, scouts, drillers, and others interested in particular wells. A considerable number of samples recently received has been contributed from the geological departments of several of the operating companies. In connection with the discussion of the well records, the writer has had occasion to refer to and utilize the data from cqttings from the numerous wells. These samples have been identified by Dr. J. A. Udden, to whom the writer is indebted for the opportunity of utilizing the data from them in this paper. Among those who have assisted from time to time in the identification of well samples in the Bureau of Eco­nomic Geology collections are V. V. Waite, E. B. Stiles, and A. H. Kemp. In the case of two of the wells used in this re­ port, namely the Goss and Schoor wells of Comanche and Eastland counties, the samples contained in the Bureau col­lection have been supplemented by the description of sam­ples from the same wells by S. G. Garrett under direction of Wallace E. Pratt of the Geological Department of the Hum­ble Oil Company. PREVIOUS PUBLICATIONS The existence of a structurally high area extending slight­ly east of north from the Central Mineral Region has become well known in recent years. This arch was depicted in a gen­eral way in a map by M. G. Cheney, published in the May, 1918, issue of the Oil Trade Journal, page 75, and in a map by Dorsey Hager accompanying a paper published in Bulle­tin 138 of the American Institute of Mining Engineers, is­sued June, 1918. In these maps the Bend formations are used in contouring the regional structure, while the present paper relates entirely to regional structure as indicated by the El­lenburger formation. In a paper entitled "Recent Knowl­edge of Formations·Below the Bend," Mr. William Kennedy has referred to a number of wells which enter the Ellenbur­ger formation in north-central Texas and concludes that they indicate a ridge extending in a northeasterly direction from the Central Mineral Region.1 A similar conclusion has been expressed by W. G. Matteson. The Oil and Gas Journal, issue of October 17, 1919, contains a paper by Lee Hager on regional structure. on the Red River, while papers relating to structural conditions within the oil fields of north-central Texas have been published by a number of other geologists. Volume 3 of the Bulletin of the American Association of Petroleum Geologists, 1919, contains the fol­lowing papers relating more or less directly to structural conditions in this area : Sub-surface Geology of the Oil Dis~ tricts of North-Central Texas, by Jon A. Udden; Geologic Structures and Producing Areas in the North Texas Petro­leum Fields, by Wallace E. Pratt; Observations on Two Deep Borings Near the Balcones Fault Zone, by J, A. Ud­den; A Review of the Development of the New Central Texas Oil Fields During 1918, by W. G. Matteson. LIMITATION IN THE DATA Now AVAILABLE The present map, as indicated by the title, is preliminary. It is based on the data now available in the Bureau of Eco­ 'The Southwestern Oil Journal, Jan. 4, 1919, p. 1. nomic Geology of the University and is expected to be re­vised as data accumulate. There are certain sources of pos­sible error among which the following, in particular, should be mentioned : The elevation of the land surface at the wells is, in all instances, to be regarded as more or less of an ap­proximation to actual levels. As already stated, in the ab­sence of other data, some elevations, as noted in connection with the wells, have been estimated from topographic maps. -These are reconnaissance maps with contours at 50-foot in­tervals. There is also difficulty in placing these wells accur­ately on the topographic map. There is thus introduced for these wells a possible error in elevation amounting to from a few feet to as much probably as 100 or 150 .feet in the case of some wells. For the wells the elevation of which is based on instrumental levels, there is likewise a considerable pos­sible limit of error in elevation. For many of these wells, two or more elevations have been recorded which seldom agree, and which vary among themselves from a few feet to as much in extreme cases as from 50 to 75 or 100 feet. Not only in the matter of surface elevations, but in the records themselves, the data as to the Ellenburger formation are approximate rather than exact. A sample of cuttings which affords a positive identification of the Ellenburger may nevertheless be indeterminate as to whether it has been obtained from the top or from some distance down in that formation. In such instances, the data from the sample may be supplemented in an important way by the data from the log. In the case of wells represented by merely a log, the probability of error in determining the top of the Ellen­burger is, of course, greater than when represented by both log and sample, and while most logs are so kept as to per­mit the determination of the dividing line between the Bend and Ellenburger formations, there are some that permit at best only of an approximate separation of these formations. Nevertheless, for regional structure, it is believed that the data now available are sufficiently exact to be of service in defining both the position and the structure of this forma­tion in north-central Texas. IRREGULARITIES IN THE TOP SURFACE OF THE ELLENBURGER PRODUCED BY EROSION As has been stated, the purpose of a map contouring the Ellenburger is two-fold. First of all, the map and text combined afford the driller the data by which to make such an estimate as it is now possible to give of the depth to this formation at any place within this area. Secondly, the map indicates in a. broad way the r~gional structure of the Ellen­burger formation in north-central Texas. In applying the map to the interpretation of structure, however, it must not be forgotten that the top surface of the Ellenburger is an erosion surface and that some of the irregularities in the formation may be due in part to erosion and not entirely to structure. It is certain, however, that while the erosion fea­ture may account for relatively minor irregularities in the Ellenburger, the major features observed and mapped in that formation are structural. EXPLANATION OF THE MAP The location of each well used in determining the position of the Ellenburger limestone is indicated to such degree of accuracy as is practicable on a map of this scale. In the case of those wells believed to have entered the Ellenburger formation, the approximate actual level of the top of the for­mation above or below sea level, as nearly as can be deter· mined, is shown by the map entry for that well, levels below sea being indicated by a minus sign preceding the number. In addition .to wells entering the Ellenburger a few have been used which, although not known to have entered the Ellenburger, are useful in mapping as showing that the for­mation lies below a given depth. In the map entry such wells are indicated by a plus sign following the entry. Dotted contours include those farther removed from known wells and hence less definitely placed than the contours shown in solid lines. · REGIONAL STRUCTURE IN NORTH-CENTRAL TEXAS AS INDI­CATED BY THE ELLENBURGER FORMATION Contours on the Ellenburger, as on the Bend, indicate a pronounced arch extending slightly east of north from the Central Mineral Region. From near the western part of San Saba County the axis, or line of maximum elevations on this arch, passes somewhat east of the center of Brown County, crosses the northwestern part of Comanche County, and lies probably somewhat east of the center of Eastland County. North of Eastland County the available data are as yet too limited to locate the ill-defined axis of the fold in the Ellenburger, which probably lies near the Stephens-Palo Pinto county line.· This fold plunges to the north, the rate of plunge varying from place to place. In San Saba and McCulloch counties, the Ellenburger is found at the surface at elevations of from 1500 to 1700 feet or more above sea level. In Young County, 150 miles to the north, the formation lies 3500 feet or more below the sea level. The plunge is probably most rapid in Brown County where it may amount to as much as an av­erage of 50 feet per mile. Farther to the north the plunge in the axis of the fold is less rapid, and over considerable distance may not exceed 25 or 30 feet per mile. A conspicuous feature of this large fold is the lack of symmetry between the west and east sides of the arch. The west limb of the arch has an approximately uniform slope, decreasing in rate of dip perhaps with the increased dis­tance from the Central Mineral Region. On the east limb of the fold, on the other hand, the r~te of slope is notably irregular, and is in general more rapid than on the west limb. In contouring, this lack of symmetry in the fold is ex­pressed by the abrupt turn.of the contours to the south after crossing the axis of the fold. On the west side of the fold the contours, when drawn to express regional structure, and disregarding such local structures as may exist in this for­mation, maintain an approximately regular course, varying in direction from north-northeast, west of the mineral re­gion, to east-northeast and in places almost east-west as they approach the axis of the fold. After crossing the axis, these contours turn shortly to the south and in some instances turn southwest, thus almost doubling back on themselves. The arch, as developed in the Ellenburger, is not a simple fold. Masses or "noses" of this formation project to the northeast. One of the best delineated of these noses is that at Desdemona. Here the contours on the Ellenburger, after making the turn at Desdemona, run west of south until again deflected to the east by another northeastward pro­jecting mass of the Ellenburger. The 2000-foot contour be­low sea level, after turning south near Desdemona, runs west of south for as much as 15 miles to the Tate and Fisher wells where it turns at right angles to a direction slightly south of east. This contour again turns south after passing the Sturkie well northeast of Comanche. Its position at the Mills County line is defined in part by the Luckie well which indicates that its course from the Sturkie well may be about due south as drawn on the map, or very possibly when more fully known the course of the contour after making the turn northeast of Comanche may be found to be west of south into Mills County. Other contours, crossing the axis of the fold, follow a more or less similar course, at least to the ex­tent of bending very shortly to the south. DISTURBED AREA BETWEEN THE BEND ARCH AND THE BAL­CONES FAULT ZONE Not only is the east slope of the major arch one of rapid and irregular dip, but observation will show that the whole area from the Bend Arch to the Balcones Fault Zone, at least that part of it in which the Ellenburger formation can now be delineated, is an area of much greater disturbance than is a similar area to the west of the Bend Arch. The northeastward projecting masses of the Ellenburger at Des­demona and northeast of Comanche have been referred to, the syncline separating these being located by the Tate and Fisher wells and expressed on the map by the deep reentrant in the contours. A very deep reentrant in the contours, in the eastern part of Mills County, indicates the location of .another structurally low area in the Ellenburger. This low area in Mills County contrasts strongly with the broad high Ellenburger mass extending into the northwestern .part of Lampasas County. The broad high area of Lampasas County is interpreted in contouring as continuing to the northeast to the Clark well in Coryell County. However, as there are at present no deep wells in northeastern Lampasas and north­western Coryell counties, this mapping of the Ellenburger lacks confirmation and may ultimately require alteration. Another low is indicated, the writer believes, by the wells of eastern Lampasas and southwestern Coryell counties, in­cluding the Grove well of Lampasas County and the Tienert and Strickland wells of Coryell County. The Gotcher well near the Coryell-Bell county line with little doubt indicates the approach of the relatively high area of the Balcones fault zone lying next to the east of the low area referred to. The number of wells reaching the Ellenburger is as yet lim­ited as compared to the large area to which this map relates, and more complications in the structure of the Ellenburger are to be expected than can now be indicated in contouring. The map should, therefore, be regarded as preliminary and drawn for the purpose of expressing the present available records of the formation. The data on which the map is based are more fully given in the pages which follow. CONDITIONS IN NORTH TEXAS The arch in the Ellenburger formation may be followed more or less definitely, as already noted, as far to the north as Young County, where by reason of the north plunge of the structure it lies at a depth of from 3500 to 4000 feet be­low sea level. That the north plunge does not continue un­interruptedly to the north state line is indicated by well rec­ords available from Clay, Montague and Cooke counties. A well on the Byers farm, 12 miles north of Henrietta in Clay County, is reported to have entered granite at 4240 feet from the surface, or at an actual level of about 3311 feet be­low sea level. A well in the northern part of Montague County is known to have entered the schists at about 3000 feet from the surface. In Cooke County, a few miles north of Myra, the Ellenburger is reported by samples at a depth of 2105 feet from the surface,1 or at an actual level of ap­proximately 1000 feet below sea level. These records indi­cate that the Ellenburger formation, where present in these counties, lies at a level much higher than in the adjoining 'The University of Texas, Handbook Series No. 1. J. A. Udden, p. 55. counties to the south. The conditions in the Red River area have been discussed by Mr. Lee Hager, in the paper to which reference has already been made. AVAILABLE DATA The data available on wells reaching the Ellenburger formation in north-central Texas are summarized in the following lists in which, for convenience of reference, the wells are arranged by counties. The wells of each county are listed alphabetically under the name of the owner of the land on which the well is located. For each well there is given the name of the company or individual by whom the well was drilled; the location by survey; the location in miles from a town or other designated place; the total depth of the well, if known; the elevation of the land sur­face at the well.; the depth from the surface to the Ellen­burger limestone; the kind of data available, whether a log or sample or both. In the case of a number of wells, al­though samples are at hand showing the presence of the Ellenburger, the log must be relied upon to determine the top surface of that formation, the samples having come from below the top of the formation. In such instances the entry showing the top of the Ellenburger is taken from the log, and there is added an entry showing the depth at which the first Ellenburger sample is available. There is added a column in the lists giving a map entry for each well on which the data are sufficiently complete to permit of its use in mapping. Except when followed by a plus sign, the map entry indicates the depth of the Ellenburger form-· ation below or above sea level, as nearly as can be deter­mined. When followed by the plus sign, the map entry shows that although the well was drilled to the depth in­dicated, the Ellenburger was not reached, and lies at an undetermined distance below that depth. · Those wells, the elevation of which is estimated from the topographic map, are indicated by the letter "T" following the entry. The elevations given for all other wells are elevations obtained from operating companies in this section and are based on instrumental levels. Following is the list of wells by counties: BROWN COUNTY ..... ~ Location from town or Name of Well and Owner Location by Survey other place Abney 1, Graham Ludlow and/Kerr County School Lands/6 mi. S, 2 E Brownwood Thomas. Surv. 272 Alvis 1, Oil States Petroleum Co. H. 'l'. & B. Ry. Co. Surv. 37 12% mi. N, 1 W Bangs Andrews 1, Pippin Oil Co. H. H. Hall Surv. 49 1'h mi. S, % E Brownwood I Baugh 1, Bartles and Dumenil and Osborn Dalton Surv. 26 7% mi. N, l'h E Brownwood Texas Co. I Burns 1, Gilman Crabtree and Sim-,C. C. Baker Surv. 7 12 mi. N, 6 E Brownwood cons Capps 1, Texas Eastern Oil Co Patrick Sullivan Surv. 7 2 mi. NE Brownwood Cross 1, A. A. Peard. E. D. Prewett Surv. 13 South county line Davis 1, Carter et al. Jas. Bird Surv. 102 5 mi. S, 1 W Bangs Fuller 1, Empire Oil and Gas Co. IC. B. Jennings Surv. 353 214 mi. W, 1'4 N Bangs Gaines 1, Sinclair Gulf Oil Co. Nancy Jordan Surv. 12 12 mi. N, 4 W Brownwood Kerr County School Lands 6 mi. S BrownwoodGehrke 1, Perry-Bencini. J no. Saunders Surv. 162 4 mi. fr. N, 'h fr. W countyHarris 1, Pennant Oil Co. line J. M. Baker Surv. N. part 8'h mi. N, 1 W Bangs Lowe 1, J. W. Collins Reuben Ross Surv. 44 3 mi. S, 1'h E Brownwood Low l, D. R. Bailey et al. Surface Depth Total Eleva­ Ellen­ Kind of Map Depth tion burger Record Entry 2610 1604 1510 Log -6 3160 1576 3035 Log -1460 2401 1316 1676 J..og -359 Sample at 1921 3310 1395 2278 Samples -883 3260 1721 3003 Log -1272 Sample at 3070 1900 1377 1874 Samples -497 2803 1417 1270 Log 147 2218 1553 2147 Log ·-594 Sample at 2190 3708 1563 2346 Log -782 . 2778 1520 2760 L eig -1240 Sample at 2763 2106 1400 Sample at 2105 3405 1625 3406 Log -1780 1450T 2766 Samples -1305 1665 1375T 1487 Log -112 ~ ~­ ~ ~ ""· ~ ~ ""'3 ~ ~ ~­ ~ ...... ~ .,.... ~· Matlock 1, Pecan Bayou Oil Co. Nevermind, Producers Oil Co. Sewell 1, E. J. McJunken et al. Sterns 1, J ewe! Oil Co. Weeden 1, Partridge Oil and Gas Co. Vestal 1, New South Oil Assn. Childs 1, F . E. Henderson, et al. Guthrie 1, Producers Oil Co. Guthrie 1, Santa Anna Indus. Co. Guthrie 1, The Sun Company Harris 1, Slick Oil Company Miller 1, Systems Oil Company Morris 4, Magnolia · Pet. Co. and Elizabeth Oil Co. Morris 3, Magnolia Pet. Co. and Elizabeth Oil Co. Morris 5, Magno'Iia Pet. Co. and Elizabeth Oil Co. Neff 1, Sinclair-Gulf Oil Co. Padgett 1, Sinclair-Gulf Oil Co. Brown County School Lanai 3% mi. E Brownwood Surv. 360 Southern part of county T. & P. Ry. Co. Surv. 3 1 10% mi. N, 5 W Brownwood A. D. Neill Surv. 41 10 mi. S. 4 W Bangs H. T. & P. Ry. Co. Surv. 51 10% mi. N, 5 W Brownwood CALLAHAN COUNTY 2757 1417 1850 Log -433 Sample at 2380 1975 1780 Log ~ 2505 1500T 2230 Log -730 ~ 2084 1515T ~ 2760 1492 2657 Log -1165 O"' ~ <:':> .... Jesse Dyson Surv. 1'h mi. E , l'h N 3755 1785 3725 Samples -1940 ~ Cross I Sealey-Hutchins 1, Sinclair-Gulf Oil IG. M. & N. Surv. 231 9 mi. N, 2 W Coleman Co. Plains J ohn Sayers Surv. 10 mi. S, 3 E Putnam 1 COLEMAN COUNTY Bond & Saunders Surv. 78 l 'h mi. S, 'h W Trickham Bond & Saunders Sun•. 110 1 1-3 mi. W Trickham H. E. & W. T. Sun· 117 7 mi. S, 3 W Trickham H . Stearns Surv. 6:J 2'h mi. S, 1 'h E Santa Anna Fort Bend County School Near SW corner Coleman Lands Surv. County David Breeding Surv. 9'h mi. N, 2 E Coleman David Breeding Surv. NE Morris 4 mi. David Breeding SllrV. N Morris 4 mi. Geo. Eubanks Surv. 173 11 mi. N, 7 E Coleman Brazoria County School i'...ds. Near SW corner Coleman Surv. 226. County c 4005 1846 Samples ~ :;::. .,.... ""· c ~ 1975 1400T Log 1904 1400T Log ~­2267 1400T Log ~ 3264 l&OOT 2625 Log -1025· c 3175 1500T 2918 Log -1418 .,.... ..... ;::.­3978 15/l3 3417 Log -1834 ~ <:':> ~ 3438 1582 3432 Log -1856 .,.... ..... :;::. ...... 3430 1578 3418 Log -1840 ~ <:':> 3425 1622 8402 Sample -1780 2 3580 1596 3445 Sample -1849 >=l Cr,; and log 3922 1882 3885 Log -2003 I-' Ol COLEMAN COUNTY (Continued) ~ O') Location from town or Location by Survey Name of Well and Owner other~ place Sealey & Smith 1, Magnolia Pet.IH. H. H. Ry. Co. Blk 2,;7 mi. N, Ph E Coleman Co. and Elizabeth Oil Co. Surv. 9 Slate l , Magnolia Pet. Co. and·J. Kaufman SUl"V. 237 123 mi. S, 2 W Coleman Elizabeth Oil Co. I Wallace 2; Robertson and Son. Armstrong 1, P. L. Tippit Bender 1, Henderson et al. Davis l, Sam Davis Oil Co. Fine 1, Lone Star Gas Co. Wm. Ferris SUl"v. 279 17 mi. S Santa Anna COMANCHE COUNTY H. T. & B. Ry. Co .. Surv. 13 3 mi. N, 2 E Comanche j 1250T 2885 Sap>ples -1635 ~ .J . P. Stevenson Surv. 3,.2% mi. E, l 'h N De Leon: 3500 1247 0 '-+.. SE part I ' 3500 1250 Jas. Walker Surv. Comyn Station ~ I Cl> E. T. Ry. Co. Surv. 35, 16 mi. E, 2'h N Comanche 4150 1350T Log -2800+ P. NW part ~ Ct;> Total Depth Surface Eleva­tion Depth Ellen­burger Kind of Record Map Entry 3610 1632 3530 Log -1898 3114 1400T 2227 Log -827 1500T 2533 Log -1033 ~ ~· Cl> ~ ""·,,... Fisher 1, Copperas Creek Oil Co. ID. H. McFadden Surv. 190 11 mi. N, 2 W Comanche 1271 3204 Log --1.933 Fritz 1, Maxwell and Ertel Geo. L. Addison Surv., SE15 mi. N, 5 E Comanche 3276 1150T 3145 Log -1995 ~ corn_er :;:::: Galloway 1, Lone Star Gas Co. H. & T. C. Ry. Co. Surv. [9 mi. S, 4% W Comanche 3525 1700T 3883 Log -1683 Cl> ,,... 1 I 15, SW corner ~· Goss 1, Humble Oil and Rfg. Co. D. & D. Asylum Lands Surv.14 mi. W Sipe Springs 3275 1532 3272 Samples -1740 ' 59, NE corner Gregory 1, Texas Penn. W. R. Gregory Surv., N 'h mi. from E, 1;3 from N 3410 1400T corner county line Hamlin 1, Manhattan Oil Co. D. & D. Asylum Surv. 23 1'h mi. N Duster / 3176 1402 315C¥ Samples -1748 Hilly 1, Gates Oil Co. L. Birdsall Surv. 54, NW 2 mi. from N, 1\4 from E 1343 334-0 Log -1997 corner county line I Kee 1, Henderson et al. ·J. P. Stevenson Surv. 10 >% mi. S, 'h W Desdemona -------­1258 3325 Samples -2057 NW corner l E. Moore Surv. 3 mi. W, 'h S De Leon Huckabee 1, Home Boys' Oil Co. Lucky 1, Thomas and Ludlow E. T . Ry. Co. Surv. 6 114 mi. from S, 'h from W county line Montgomery 1, :i.raxwell and Ertel Robt. Page Surv., SE cornerl5 mi. E Mercer's Gap Moore 1, Gulf Production Co. E. Whitesides Surv. 71 12 mi. E, 2'h S Comanche Pittman 1, National Refining Co. H. & T. C. Ry. Co. Surv. 42 4 mi. N, 4 W De Leon Rudd 1, Roxana-Wallace Oil Co. D. and D. Asylum Lands North county line, lO'h mi. Surv. 17 I from NE corner Small 1, Humble Oil and R~fining,D. and D. Asylum Lands 2 m i. N , '4 E Sipe Springs Co. . :ilUl'V. Shearer 1, Texas Penn. G. Fay Surv. 53, N corner I'h mi. from N, l 'h from E l ' county line Studeville 1, Miller, Knight and1E. Whitesides Surv. 71 1.2 mi. E, 2'h S Comanche Chass. Sturkie l , Comanche Oil Assn. Asa Hoxey Surv. '~ mi. E Hasse, 7'%, E, S'h N Comanche Tate 1, Crawford and Flynn H. & T. C. Ry. Blk. 2, Surv.I G'h mi. W De Leon 7 CORYELL COUNTY Clark 1, Benedum & Trees, Francis! G .. W. Carlisle Surv. Keystone Texas Oil Co. Gotcher 1, N. Y. Syndicate. ,W. T. Whitley Surv. Strickland 1, Buckeye Mid-Kansas. [J ohn Winn Surv. Tienert 1, N. Y. Syndicate. Elizabeth Jones Surv. 9 mi. W, 1 N 'Gatesville 2%. mi. W, 'h S Coppet'as Cove l 'h mi. S, '%, W Pitcock l 'h mi. W, 2 N Copperas Cove? EASTLAND COUNTY Allen l , Gulf Production Co. IWm. Fields Surv. 4%. mi. S, 3'%. E Ranger Alsobrook 1, Havermeyer & Sea-H. T. & C. Ry. Surv. 14 l 'h mi. SW Gorman nians. Barnes 1, Prairie Oil and Gas Co.IF. P. Barnall, Blk. 40, Surv.1 657, SE corner 12 mi. N, 2 W Ranger 3500 1238 3456 1484 Samples -1972+ and log 3500 1420 3245 Log -1825 3824 3410 1193 1325T 3776 Log -2583 l'tj..... 3076 1300 3075 I.,og -1775 ~ ;:l C" 1500T· 3313 . Log and -1813 ~ Sample ~ at 3345 ~ "l 3450 1400T "l:j 0 3850 1150T ~ ~ 3350 1200T 3335 Samples -2135 .,..,..""·0 3323 1369 3301 Log -1932 ;:l "" ;:l· ~ 3630 .870 3465 Samples -2595 0 "l.,..,.. ~ 3035 1132 3025 Log and Sample -1893 CJ at 3035 ~ 3628 946. 3615 Samples -2669 .,..,.. "l 3384 1094 3384 Samples -2290 ~ ..... >-3 ~ ~ !;:) 4010 1446 3765 Log -2319 i:r,, 3525 1400 3190 Log -1790 ..... -;:i 4300 1584 4080 Log -2496 EASTLAND COUNTY (Continued) ...... Location from town or Surface Depth Name of Well and Owner Location by Survey other place Total Eleva-. Ellen­Kind of Depth tion burger Record -I~~~'.'.'.__~=--;:;:---: Wm. Van Norman Surv. Brashear 1, Leon Oil Co mi. S, 2-3 W Ranger Brashear 2, Leon Oil Co. Wm. Van Norman Surv. mi. S Ranger Brashear 1, Westheimer et al. !Wm. Van Norman Surv. 5'h mi. S, 2-3 W Ranger Branford 1, Prairie Oil and Gas Co. Rosseau Surv. 25 5 mi. S, 2% E Eastland Brown 1, Central Oil Development G. E. Moore Surv. 1 mi. E, 'h N Desdemona Co. Cooke 1, Texas & Pacific. N. Cooper Sur-v. 13 mi. N Ranger Connellee 1, Benedum & Trees. N. Dssury ~urv. 13 mi. S, % E Eastland Duffer 1, Prairie Oil and Gas Co. S. N. Mathias Surv. 1 mi. E, 3'h S Ranger 1 Eppler 1, Connollee and Aguire. Wm. De Moss Surv. 3'h mi. NE Gorman Falls l, Prairie Oil and Gas Co. E. Finley Surv., NW part 3% mi. S, l'h W Ranger Fee 1, Sun Company. H . T. & C. Ry. Blk. 4, NE 6'h mi. W, 1 N Ranger cm..uer Fee 1, Texas Pacific Coal and ·Oil Robertson County School 8 mi. E, 1% S Ranger Co. Lands, SE part Hagaman 1, Lone Star Gas Co. W. C. & C. Boswell Surv. 1'h mi. NE Ranger Holcomb 1, Cosden Oil Co. J. House Sur-v. 1 mi. NE Eastland Map Entry -2151 ~2238 -2095 -2514 -2196 -2234 -1902 -2244 -2462 -2270 -2273 -2292 -2057 -2478 -2121 -2300 -2171 -2245 -2131 400U 1477 3628 Log 1471 3618 Log 1460 3615 Log 3955 1479 3717 Log 1450T 3545 Samples 4200 1546 4187 Sarnp!es 3800 1541 3n1 Log 3770 1446 3680 l;og 1356 3238 3700 1441 3685 Log 4012 1538 400() Lqg 3710 1250T 3520 Log 3745 1426 3699 Log 3777 1485 3777 Sample ~ ~­ ~ ~ .... """" ~ ~ "-3 ~ ~ Clo "' Oj ~ ..... ~ """" ~­ Mann 1, Atlas Oil Co. Thos. MaJ!ryne Surv. (Cen­ 8 1-3 mi. E, 2 1-3 N Carbon ter) Parrock 1, States Oil Corporation. H. & T. C. Ry. Co. Blk. 4,1614 mi. N, 7'h E Eastland Surv. 7 Pitcock 1, Texas and Pacific Coal Wm. Frells Sur-v. 2 mi. S Ranger and Oil Co. Rush 1, Mid-Kansas Oil and Gas Co. E. Finley Surv. 13 mi. S Ranger Shoor 1, Humble Oil Co. H . T. & C. Ry. Co. Blk. 3, 6 mi. S, 2 E Cisco Surv. 50 Stewart 1, Leon Oil Co. !Wm. Van Norman Surv. 6 mi. S, 1 W Ranger UndP.rwood 1, Systems Tidal OH Co. D. S. Richardson Sur-v. 4 mi. W, % N Desdemona 3500 1371 3428 Log 40.83 1619 4078 Lqg 4020 1454 3575 Log 3945 1420 &720 Log 3790 1608 3769 Samples 1413 36~ Log 1379 3510 Log Ward 1, New Domain Oil Co. ,..,xle, N part 4'h mi. N, 1 E Cisco 3976 1415 3825 Log -2410 ,J. D. Sample Vaught 5, Atlantic Production Co. ,Wm. DeMoss 3 mi. W, 1'h S Desdemona 3245 1250T 3165 Samples -1915 Stockton 1, Cosden Oil Co. Wm. DeMo.ss 1South of county line 3250 1322 3180 Samples -1878 ERATH COUNTY t:t:i .,_ ~ 4018 1250T Samples -276S +Perkins 1, Baltimore-Texas Syndi 1Q. Tarbox· Surv., SW corner.7 mi. from W, 8 from N ~ <::r' Randolph 1, Burt and Griffith C'ounty line cate. S. Blythe Surv. mi. S Dublin ; 14 mi S, 4510 1400T Log -3110 + 7 W Stephenville ~ (to 3860 1383 3755 Sample -2505 ~ Stacey, Sinclair Oil Co. Thompson 1, Gulf Production Co. F. R. Lubbock Surv., E ·side,' 9 mi. S, 2 W Thurber K. K. Koontz 3·mi. S, 14 E Stephenville 4355 1050T ? Log -3305+ "":l 0 HOOD COUNTY ~ Followell 1, Sinclair Gulf Oif Co. 4820 980 Log -3840+ ~ Isaac Eaves Surv., NE corneri2 mi. fro'." N, 2 from w1· .,.... I county !me ! LAMPASAS COUNTY Abney Well, City_of Lampasas Near Santa Fe Depot, Lam­ pasas Conradt 1, Robarts et al. E. T. Ry. Co. Surv. 1, SEl5 mi. N, 2 W Lometa one-fourth Grove 1, Price et al. · IR. W. Brown Surv. 6 mi. N, 1 E Lampasas Hill 1, Hill River Oil Co. (Cham-,David Evans 8 mi. -5 Lometa pion). McCree 1, Nelms-Marvin Oil Co. IWm. F. Nicholson Surv. t' 110 mi. W, 2 S Lampasas NW corner Smith 1, C. H. White T. R. Stiff Surv. 16, S side/ 13 mi. W 1 S Lampasas White 1, Howell et al. Wm. Todd Surv. 42, NW part 3 mi. S, 7 W Lometa White 1, Texoleum Petroleum Co. !Hill Surv. . 113% W, l'k N Lampasas Whittenburg 1, Western Lampasas John Boyd '>m·v. 612, Nt} 3 mi. W Lometa \/ cornet .,., 0 ~ ~­ 2000 lOOOT 470 Log 530 ~ 0 2001 1500T 188CI Log -380 .,.... ~ and ~ Samples ("'.) 2005? llOOT flample -1005+ ~ 1602 1450T 417 .Log 1033 .,.... ~ 1120 1400T 20 Sample 1380 .,_ 1--3 1400T 29 Sample 1371 (to R 1021? 1250T 136 Logand 1114 ~ Cl> Samples at 1021 1250T At surface 1250 .... 1450T 998 Sample 452 ~ N) McCULLOCH COUNTY Location from town. or Name of Well and Owner Location by Survey other place l'h mi. SSE Brady Beasley 1, Dallas Milburn Valley Baumgartner 1, Texas Hurst Synd, IP. H. Schaff Surv. ·10.8 2'h mi. N, 2'h E Mercury Oil Co. Cawyer l, Burford & Brimm. P. Winkle D. Mechels Surv. 968, NW:3 mi. SE Mercury corner Crews 1, Southwestern Pet. Co. 1 U. Heinrich '11 mi. SW Rochelle Craig 1, Thomas et al. Jc. Usner Surv. 4'h mi. N, 1 W Melvin Morgan 1, J. E. Morgan State School Land•, Surv. 2 2 mi. NNW Brady 1 Sellman 1, Texas Eastern Oil Co. IC. Beag Surv. 90·1, NWl3'h mi. ENE Rochelle corner White 1, Henderson et al. B. .fl. & F. Ry. Cn. '5urv.ll0 mi. S, 4 W Whiteland 1, SW corner White 1, Thoinas et al. Fisher and Miller Surv. 258611 mi. E Whitehead Zella 1, Prairie Oil and Gas Co. H. & T. C. Ry. Co. Surv. H9.14 mi. NW Lohn SW corner MILLS COUNTY Total Depth 1253 2526 1422 1960 2565 2005 1401 3280 34.66 Surface Eleva­tion 1650T 1280 1422 1675T 185<1T 1700T 16oOT 2050T 1'750T 1500T Depth Ellen­ burger 61 945 725 605 2065 420 610 1285 100.8 1870 Kind of Record Lqg Log and Samples at 1012 Log Log Log Log and Samples at 680 Log and Samples at 1470 Log Log Log and Samples at 2050 Map Entry 1589 335 697 1070 -215 1280 1040 765 742 -370 Cryer l, Mills County Oil Co. M. Clark Surv. 14 IJ. I Harrison & Slayden l, Venture Oil,T. Carroll Surv. 401 Co. Howell 1, Atlantic Production Co. M. Kenedy Surv. 647 12 mi. W, 5 N Goldthwait~.-------­14 mi. W, 8 .N Goldthwaite I 3065 1317 1271 188~ 1540 Log and Samples lt 1885 Log -468 -269 4'h S, 3 W Goldthwaite I 2440 1228 2007 Log -779 .c::: ;:S ~· ~ .... Cl:> .,..... '""'· «:: 0 ...... 1--3 ~ ;-s ~ Cl:> bj £: ~ .,..... ~­ Locklear 1, Texas Co. Tysbn 1, A. R. Forstner et al. Ware 1, Ware Haywood Oil Co. Weston l, Clarion OH Co. 8 ini. W, 1 N Goldthwaite Sam' Cates T. & N. 0. Ry. Co. Surv. 2110 mi. W, 10 N Goldthwaite H. Thurmester 6 mi. S, 1 E Goldthwaite Caldwell County School Lds.j4% mi. W, 1% N Goldth-Surv. 112 waite Whittenburg 1, Stirling Oil Co. A. Thompson Surv. 2 2 mi. E Ebony Young 1, Fidelity Oil Co. I I PALO PINTO COUNTY 2715 1248 2035 Log -787 2520 1372 2320 Log and -948 Samples at 2410 ~ 2510 1248 2473 Log and -1225 ...... ~ Samples ;2 at 2505 O' 2400 1338 2118 Samples -780 ~ ~ 1285' 1435 1175 Log 260 "l ~ c Abrams 1, Sinclair Gulf Oil Co. !Texas and Pacific Surv. 4313% mi. S Mineral Wells I 3998 1305 Log -2693+ ~ Chestnut 1, Empire Gas and Fuel Geo. Green Surv. A-207, cen-8% mi. S, 1% W Mineral Co. I ter W one-half Wells Dye 1, ·Roxana P et. Co. Texas !:mi. Lds. Co. Surv.,3% mi. from N, 9% from E 879 Edmondson 4, Empire Gas andlDaniel ht.arn Surv. 46 Fuel Co. McDonald 1, Texas Co. IT. & P. Bile. 1, Surv. 31 RoGgers C& Rhea 1, Prairie Oil and Surv. 166, S~ corner· ··--~--· as o. .....,, , Seaman, Roxana Pet. Co. T. & P. Blk. 3, Su~v.·· ~ Smith 1. IJohnson Bros. Watson l, Empire Gas and Fuel Co"Surv. 48 county line 7 mi. S, 1% W Mineral Wells 2 mi. W , 1 S Palo Pinto 614 mi. E Gorman 9% mi. from N and 1 from W county line 21h mi. E Mineral Wells 5 mi. W, 5 N Palo Pinto RUNNELS COUNTY Russel 1, Gulf Prod. Co. !James Hughes ISE part of county <'"+­ 4210 1122 Log -3088+ c""· ;2 3933 940 Log -2993+ ~­ 4710 1120 Samples -3590+ ~ c "l <'"+­ 4665 loa3 4635 Samples -3602 ;;s­ 4052 950T Log and -3102+ (":) Samples 4535. 1248 4519 Log --'3271 ~ <'"+­ ~ 4392 847 Log -3545+ ...... 4053 979 Log -3074+ ~ ~ ~ ~ 3505 1677 3448 Sample -1771 N> """"' SAN SABA COUNTY N> N> Nail 1, Benedum and Trees. Bobo 1, Texas Pac. Coal and Oil Co. Gaston 1, Texas Pac. Coal and Oil Co. Veale 1, Texas Pac. Coal and Oil Co. Surface Depth Total Eleva-Ellen-Kind of Map Depth tion burger Record Entry 1380 • 1362 805 Log .and 557 Sample at 1250 1425T 605 Drilling 820 ~ Report i;• SHACKELFORD COUNTY ~ ;'; ~ ~ IE-T. Ry. Co. Surv. 50 110 mi. N, 2 W Albany I 4465 1525T ? Sample -2930+ c STEPHENS COUNTY T. P. Blk 6, Surv. 67 A. S. Johnston T. P . Blk. 6, Surv. 74 --... 2 mi. S, 1 E. Frankell I 4311 1453 ? Log -2658+ ~ ~ South side Brazos, 7 mi. from 4650 1131 4650? Samples -35197 ~ W county line 6 mi. S, 2 E Franken 4018 1502 ? Log -2516+ I ~ ~ Arnold 1, Texas. Co. !Johanna and Lee Surv. S 110 mi. WNW Graham 4711 1270 ? Samples -3438+ ;:sI W corner YOUNG COUNTY ~ .,... ""· SUMMARY BY COUNTIES In the following pages the data on the Ellenburger form­ation are summarized, the discussion being arranged by counties. BROWN COUNTY At the south line of Brown County the Ellenburger, as indicated by the Riley Cross well, lies at a depth of 1270 feet from the surface. Near the west line of the county four miles from the north boundary, the same formation as determined from the record of the Harris well lies 3405 feet from the surface. Using the data available on eleva­tions for these wells it appears that the formation at the south line of the county, somewhat east of the north-south central line, lies as much as 147 feet above sea level (Cross well). In the northwestern part of the county, as indi­cated by the Harris well, the formation is to be expeCted at a depth approximating 1780 feet below sea level. The other wells recorded show for the formation positions inter­mediate between those mentioned. The axis of the large Ellenburger fold lies somewhat east of the center of the county, and plunges to the north at a rate of between 40 and 50 feet per mile. On the west slope of the arch, the dip in the Ellenburger to the northwest appears to be be­tween 90 and 100 feet per mile. On the east limb, the dip, although less definitely determined, is much more abrupt. The dip in the Ellenburger in this and other counties is in­terrupted and in places reversed by local structures not indi­cated on this small map. CALLAHAN COUNTY Records have been obtained of two wells entering the Ellenburger formation in Callahan County. These are the Vestal well of the New South Oil Association, and the Child well of F. E. Henderson, both of which are located in the southeastern corner of the county. The Ellenburger was entered in the Vestal well, as. is shown by samples, one of which is said to come from 3725 feet from the surface, or 1950 feet below sea level. Oil in commercial quantities, was obtained from this well at a depth reported as about 3755 feet from the surface, and hence within the Ellen­burger formation. The Childs well, located a few miles northwest of the Vestal, also entered the Ellenburger form­ation. The record at hand, however, is not sufficiently ex­act to determine the level of the top surface of the forma­tion in this well. COLEMAN COUNTY In the southern part of Coleman County near the north­south center line, the Ellenburger as indicated by the Slate well of the Magnolia Petroleum Company, lies at a depth of 2227 feet. Near the southwest corner of the county, the Padgett well of the Sinclair-Gulf Company reached the Ellenburger at a depth of 3445. The well nearest to the northeast corner of the county reaching this formation is that of the Sinclair-Gulf Oil Company on the Neff property where the Ellenburger appears to have been reached at or near a depth of 3402 feet. The maximum recorded depth to the Ellenburger in this county is that of the Sealey­Hutchins well, nine miles north and two miles west of Cole­man, where it lies at 3885 feet. In the southeast corner of the county the Ellenburger may be expected at or near sea level, while in the northwest corner of the county it passes to a depth of between 2000 and 2500 feet below sea level. The dip in the formation in this county is thus to the north­west. COMANCHE COUNTY The axis of the Ellenburger arch passes through the northwestern part of Comanche County, and the dip in the · formation in this county accordingly is in general towards the east. In the Goss well near the northwest corner of the county the Ellenburger lies at a depth of 3272 feet from the surface, while in the Fine well of the Lone . Star Gas Company in the southeastern part of the county this form­ation lies more than 4150 feet below the surface. In the western part of the county the Ellenburger pro}?ably lies, over a small area, as high as 1500 feet below sea level, while at the southeast corner of the county the level is with little doubt fully 3000 feet below sea level. The course of the contours in crossing this county has already been referred to. While the dip in the Ellenburger formation on the west side of the arch in Coleman County is, as already noted, in general to the northwest, the dip in Comanche County on the east side of the arch, although varying, is to the east than to the northeast. CORYELL COUNTY Of wells drilled in Coryell County up to the present time, four are known to have penetrated the Ellenburger forma­tion. The Gotcher well in the southeast corner entered the Ellenburger at 3025 feet from the surface, or 1893 below sea level. From this well north to the Tienert well the dip in the Ellenburger is rapid, amounting to 397 feet in two and one-half miles. Continuing north to the Strickland well, the dip is much less rapid, amounting to 379 feet in seven miles. The Clark well, about thirteen miles north of the Strickland, entered the Ellenburger at 3465 feet from the surface, or at 2595 feet below sea level, the formation being actually at a higher level than in the Strickland well. I11 contouring in this county the relatively high Ellenburger is interpreted as a northeast extension from the Mineral Region. The Strickland and Tienert wells are regarded as probably associated with a structurally low area, making a sharp reentrant_ in the countours similar to that indicated by the Ware well in Mills County, and by the Tate well in Comanche County. EASTLAND COUNTY The axis of the Ellenburger arch passes, as nearly as can be judged, somewhat east of the center of Eastland County. On the south border of the county the Ellenburger as indi­cated by wells near and west of Desdemona, lies at a depth approximating 3000 feet from the surface. At the north line of the county north of Ranger this formation is found, as indicated by the Cooke and other wells, at a depth of more than 4000 feet from the surface. In the northwestern part of the county the depth to this formation is with little doubt considerably in excess of 4000 feet. When reduced to sea level datum the Ellenburger in this county is found to vary from less than 1800 feet below sea at the south line of the county to more than 2500 feet below sea in the north and northwest parts of the county. Of the considerable number of wells that have entered this formation in Eastland County twenty-five are entered on this map. Of the East­land County wells not shown on the map a few have been omitted to avoid crowding on a map of this small scale, while others have necessarily been omitted owing to lack of sufficiently exact data regarding either location of the well or depth to the Ellenburger formation. ERATH COUNTY Record has been obtained of only one well entering the Ellenburger in Erath County. This is the Thompson well of the Gulf Production Company located near the Eastland county line. In this well the Ellenburger was entered at about 3755 feet from the surface, or at the level of about 2505 feet below sea. Other deep wells of this county noted on the map are the Perkins well in which the Ellenburger lies more than 4018 feet below the surface, and the Ran­dolph well in which, as nearly as can be judged from the log, this formation had not been reached at 4510 feet from the surface. HOOD COUNTY The Ellenburger formation has not been reached by any well in Hood County of which the writer has record. The Follow:ell well of the Sinclair-Gulf Oil Company indicates that the formation in the northwest corner of the county lies more than 4820 feet from the surface. The actual .level of the Ellenburger at the west side of this county probably approximates 4000 feet below sea level. LAMPASAS COUNTY In Lampasas County the Ellenburger lies at the surface over a limited area in the extreme southwestern corner. From these surface exposures it is observed to dip to the north, and to the east. In the northwest part of the county it is entered in the Robarts well on the Conrad Ranch at about 1880 feet below the surface, indicating a dip of not less than 1600 feet between this well and the south line of the county. To the east along the south line of the county the formation likewise dips rapidly, and at the Whitis well near Kemper lies at an undetermined depth, but evidently more than 1000 feet below the surface. To the northeast the dip is more rapid, and in the Grove well, six miles north of Lampasas, the formation is reported to lie more than 2000 feet below the surface, which indicates, if the record . is correct, a dip of more than 3000 feet in a distance of about fifteen miles. With regard to sea level datum, the formation varies from 1300 or 1400 feet above sea in the southwestern part of the county to more than 1000 feet below in the eastern part of the county. McCULLOCH COUNTY The Ellenburger formation lies at the surface in the soutbeastern part of McCulloch County. It dips to the north and more rapidly to the northwest. Near the west line of the county it is found in the Craig well at a depth of 2065­feet from the surface. In the southeastern part of the county the formation lies at a level approximating 1500 feet above sea, while in the Zella well to the northwest it is found at a level approximating 370 feet below sea, the dip to the northwest amounting to as much as about 100­f eet per mile. MILLS COUNTY In the northwestern part of Mills County, the Ellenburger formation, as indicated by the Whittenberg well, lies at a depth of about 1175 feet from the surface. In the north­ern part of the county near the Comanche-Brown county line, this formation is found in the Tyson well at a depth of 2320 feet. From the northwestern part of the county the Ellen­burger evidently dips rapidly east as well as north. The data on these wells are not sufficiently exact to permit a very close estimate on the rate of dip, although the maxi­mum dip may be as much as between 100 and 120 feet per mile. These approximate data are derived from a consid­eration of the Howell, Tyson, and Whittenburg wells, all of which are located in the west one-half of the county. No wells in this county are known to reach the Ellenburger east of Goldthwaite. PALO PINTO COUNTY Near the west line of Palo Pinto County, the Ellenburger formation, as indicated by the Seaman well, lies at a depth of 4519 feet from the surface. Three miles southwest of Palo Pinto this formation is found in the McDonald well 4635 feet from the surface, while in the eastern part of the county, as indicated by the Edmondson well, it lies more than 4710 feet from the surface. From somewhat less than 3000 feet below sea level in the southwestern part of the county this formation dips to probably more than 4000 beet below sea level in the northeastern part of this county. RUNNELS COUNTY The Ellenburger is known from one well in the south­eastern part of the county, where it lies at a depth of 3448 feet from the surface. SAN SABA COUNTY The southern part of San Saba County lies within the belt of surface exposures of the Cambrian formations, in­cluding the Ellenburger formation. To the north these formations pass beneath later formations, and near the north county line the Ellenburger, as indicated by the Cum­mings well, lies about 805 feet below the surface. STEPHENS COUNTY The Gaston well near the Brazos River in the northwest­ern part of Stephens County is regarded as possibly having entered the Ellenburger formation at 4650 feet from the surface, or at the actual level of about 3519 feet below sea level. A number of other wells drilled in this county ex­ceed 4000 feet in depth. Of these, however, no record has been obtained by the writer indicating the presence of the Ellenburger formation. YOUNG COUNTY The Arnold well of the Texas Company, northwest of Graham in Young County, is reported to have entered the Ellenburger formation at 4711 feet from the surface. Sam­ples obtained by the writer at 4708 feet indicate, according to determinations made by Dr. J. A. Udden, the Bend at that depth. INDEX PAGE Abney welL-------------------------14 Abrams well------------------------21 Allen welL--------------------------17 Alsobrook weJL______ --------------17 Alvis well---------------------------14 American Association of Petroleum Geologists ------------------------7 Andrews weJL_____ -----------------14 Arch of t)le Ellenburger_____________ 9 Area Between Bend Arch and Bal­ cones Fault Zone__________________ 11 Armstrong well______________________ 16 Arnold weJL______________________22, 29 Balcones Fault Zone_______________ll, 12 Barnes well____________ -------------17 Baugh weJL_________________________ 14 Baumgartner well________ -----------20 Beasley welL------------------------20 Bell County___________ --------------12 Bender welL__________ --------------16 Bend formations_____________________ 7 Bobo weJL__________________________ 22 Branford well_______________________ 18 Brashear wells-----------------------18 Brown County_________________lO, 14, 23 Brown weJL_________________________ 18 Burns welL-------------------------14 Callahan County__________________l5, 23 Capps weJL _________________________ 14 Central Mineral Region_____________ _ 5 Cheney, W. G,_______________________ 7 Chestnut well------------------------21 Child well__________ -----------------23 Childs well__________________________ 15 Clark welL--------------------11, 17, 25 Clay County_________________________ 12 Coleman County___________________l5, 24 Comanche County______________lO, 16, 24 Connellee welL______________________ 18 Cummings well_____ --------------22, 29 Conradt welL___ __________________l9, 27 Contour map_____ ___________________ 9 Contours on the Ellenburger--------~-10 Cooke County_________________ ______ _ 12 Cooke weJL_______________________l8, 26 Coryell County_________________ll, 17, 25 Cowyer well_______________________ __ 20 Craig we}J________________________ 20, 27 Crews welJ________ ------------------20 CrosJ welL____________________ ___l4, 23 Cryer well___________________________ 20 Davis well (Brown county) __________ 14 Davis well (Comanche county) _______ 16 Desdemona, structure at______________ 11 Dip in the Ellenburger________ ______ 10 Duffer well--------------------------18 Dye welL ____________________________ 21 Eastland County_______________ lO, 17, 25 Edmondson welL__________________2l, 28 Elevation ----------------------~--6, 8 Ellenburger formation in Cooke County ---------------------------5 North plunge of Arch of Ellenburger_ 10 Regional Structure of Ellenburger____ 9 Eppler we!L_________________________ 18 Erath CountY--"------------------19, 28 PAGE Erosion on the Ellenburger___________ 9 Falls well___________________________ 18 Fee well•----------------------------18 Fine welL________________________ l6, 24 Fisher well_______________________ll, 16 Followell weJL____________________ 19, 2o Fritz welL __________________________ 16 Fuller welL-------------------------14 Gaines welL_________________________ 14 Galloway No. L--------------------16 Garrett, S. G------------------------6 Gaston No. 1_____________________ 22, 29 Gehrke welL------------------------14 Goss No. i_ ____________________ 6, 16, 24 Gotcher weJL__________________l2, 17, 25 Granite in deep wells----------------12 Gregory No. L--------------~-------16 Grove weJL_______________________l2, 27 Guthrie wells------------------------15 Hagaman No. L ____________________ 18 Hager, Dorsey___________________ .___ 7 Hager,. Lee________________________ 7, 13 Hamlin No. L ______________________ 16 Harrison and Slayden No. L ________ 20 Harris wells__________________14, 15, 23 Heatherly No. L ____________________ 22 Henderson, F. E·-------------------23 Hill No. L _________________________ 18 Hilly No. L ________________________ 16 Hood CountY---------------------19, 26 Howell ___ _______________________20, 28 Huckabee No. L--------------------17 Humble Oil Co._____________________ 6 Kee No. L _________________________ 16 Kemp, A. H .------------------------6 Kennedy, Wm.______________________ 7 Lampasas County_____________ll, 19, 27 Lampasas well----------------------19 Locklear No. L------------~--------21 Low No. 1--------------------------14 Lowe No. L------------------------14 Luckie well______"________________ ll, 20 Magnolia Petroleum Co. _____________ 24 Mann No. L ________________________ 18 Map --------------------------------9 Matlock No. L---------------------15 Matteson, W. G._________________ ____ 7 McCree No. L----------------------19 McCulloch County_____________lO, 20, 27 McDonald well______ ______________21, 28 Miller No. L-----------------------15 Mills County__ .·-------------11, 20, 28 Montague County____________________ 12 Montgomery ------------------+-----17 Moor No. L------------------------17 Morgan No. L----------------------20 Morris wells-----------------5, 6, 7, 15 Nail No. 1--------------------------22 Neff welL ________________________l5, 24 Nevermind -------------------------15 New South Oil Association___________ 23 Padgett well______ ---------------15, 24 Palo Pinto County__________5, 10, 20, 28 Parrock No. L---------------------18 Perkins well______________________l9. 26 Pitcock No. L----------------------18 University of Texas Bulletin PAGE Pittman No. L----------------------17 Pratt, W. E._______________________6, 7 Red River______________________ __ _5, 13 Robarts well________________________ 27 Rogers and Rhea No. L _____________ 21 Rudd No. L ------------------------17 Runnels County__________________ 21, 28 Rush No. L -------------------------18 San Saba County______________ lO, 22, 29 Schists in deep wells ________________ 12 Sealy and Smith No. !___ _________ ___ 16 Sealy-Hutchins No. 1__ ___________15. 24 Seaman welL_____________________2l, 28 Sellman No. L----------------------20 Sewell No. L _______________________ 15 Shackelford County__________________ 22 Shearer No. L----------------------17 Shoor welL _______________________6, 18 Sinclair-Gulf -----------------------24 Slate welL________________________l6, 24 Small No. !________________________ _ 17 Smith No. i_:____________________l9, 21 Stacey -----------------------------19 Stephens County___ __ _____ ___ _lO, 22, 29 Sterns No. L-----------------------15 Stewart Nci. L----------------------18 Stiles, E. B.------------------------6 Stockton No. !___ __ _________________ 19 Strickland weJ]________ ______ ___ l2 17, 25 PAGE Studeville No. !_____ ___________ _____ 17 Sturkie well______________________ ll, 17 Summary --------------------------23 Tate No. i_______________________n , 17 Tienert ----------------------12, 17, 25 Thompson weJL __________________19, 26 Topographic map__________________ 8, 13 Tyson wells_______________________21, 28 Waite, v. v.________________________ 6 Wallace No. 2-----------------------16 Ward No. L-----------------------19 Ware No. L ------------------------21 Watson No. L __ ____________________ 21 Weeden No. L----------------------' 15 Weston No. L----------------------21 White No. L----------------------19, 20 Whitis well_________________________ 27 Whittenberg well____________________ 28 Whittenburg No. 1_____ ___ _____ __19, 21 Udden, J. A·----------------------6, 29 Udden, Jon A.___.·----------------7 Underwood No. L -------------------18 United States Geological Survey_____ 6 Vaught No. 5-----------------------19 Veale No. !______ ____ _______________ 22 Vestal wel1________________________5, 23 Young County______________5, 12, 22, 29 Young No. 1------------------------21 Zella well________________________20, 27 Bureau of Economic Geology and Technology, Bull. No. 1849 J. A. Udden, Director • . HARDEMAN \ '-. '-· -....-! -·-· WILBARGER WICHITA • I • I GR AN\T£ AT -3:311 I FOARD I • I I L __ . --.. -. -T -1 • • -..... -.311"1-+ --... /~ ~ CL AY I j I • MONTAGUE I • I • I KNOX ARCHE R • I I , I -_ __ ·__J__, I , I --· -·t-· I • JONES . ­ / ;i:{~.....o.___;,;;MILES s""'""~--""~s=..;:',O Preliminary map to show the underground position of the Ellenbur ger formatio:i in a part of north central Texas. By E. H. Sellards. Sea level datum. Contours on the top surface of the Ellen burger. The minus sign indicates elevations below sea level.