CORNELL UNIVERSITY LIBRARY ENGINEERING COBNELL UNIVERSITY LIBRARY 3 1924 059 202 097 Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924059202097 'B-S9-S19-5in University of Texas Bulletin No. 1869: December 10, 1918 Okla. Geol Survey THE GEOLOGY OF EAST TEXAS By E. T. DUMBI^ COITSUI^TIH'Q QEOtOaiST SOUTHEBN PACTPIC COUPAN-T BTTBEAU OP ECOITOMIC QEOI^OGT AUD TECKSrOlOGT DiTision OP Ecoirowio OEozioaT J. A. VDDEN, 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 ot 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 .... It is the only dictator that freemen acknowl- edge and the only security that free- men desire. Mirabeaa B. Iiamar V TABLE OP CONTENTS Page Preface 1 CHAPTER I — Introduction 3 The Region 3 Literature 5 CHAPTER II — Pre-Cretaceous 11 Cretaceous 13 Lower Cretaceous^Comanchean 14 Trinity 14 Fredericksburg ■. . 15 Washita 16 Comanchean Sections 18 •J!v6nts at Close of Comanchean 19 Salt Basins 20 Upper ■ (Cretaceous 20 Woodbine , 21 Eagleford 21 Austin Chalk ■ 22 Taylor and Navarro 23 Upper Cretaceous Sections 23 Events at Close of Upper Cretaceous 24 Folds and Domes 25 Sabine %Peninsula 26 CHAPTER III — Tertiary 28 Introduction 28 Tertiary Formations of East Texas 29 Tertiary Sections 29 Eocene ■ 30 Midway 30 General Character and Thickness 31 Deposition and Relation to Underlying Beds 31 Area of Outcrop 32 Details of Section • 33 Fossils 36 Wilcox 37 Deposition and Areal Distribution 38 Correlation with other Areas 39 Sabine Phase 40 Sabine River Section 40 Lignitic Phase 45 General Character and Area 45 Brazos River Section 48 Mapped Area 49 Santa Fe Railway Section 50 Fo^ils ^2 Close of Lower Eocene 54 iv Table of Contents Page CHAPTER IV — Eocene, continued: Claiborne 56 Introduction 56 Deposition and Character 57 Distribution 59 Topography 5^ Correlation with other Areas •. 60 Carrizo ■ ■ 61 Name 61 Character 61 Area of Outcrop 62 Marihe 64 Mt. Selman ,. 65 Name and Occurrence 65 Character and Relations 66 Cook's Mountain 66 Name and Occurrence 66 Character and relations 67 Nacogdoches 67 Sabine River Section 67 Santa Fe Railway Section 74 San Augustine Section 75 H. E. & W. T. Ry. Section 78 Nacogdoches Beds 79 St. L. & S. W. Section 86 Trinity River Section , 89 Cook's Mountain Section 92 Wheelock Section 94 Brazos River Section 97 CHAPTER V — Eocene, continued: Claiborne, continued: Yegua 102 Name 102 Type Section 102 Age 106 Mapped Area 108 General Character '. 108 Sabine River Section 110 Santa Fe Railway Section Ill T. & N. O. R. R. Section Ill St. L. & S. W. Ry. Section 112 H. E. & W. T. Ry. Section 117 Texas Southeastern Ry. Section 119 I. & G. N. Ry. Section ; 122 Trinity River Section 125 Brazos River Section ; 129 Rio Grande Section 130 Table of Contents v _ Page CHAPTER VI — Eocene, continued: Claiborne, continued: Fayet|e 134 Name 134 Type Section 134 Rio Grande Section 136 Mapped Area 139 Close of the Claiborne 143 CHAPTER VII — Eocene continued: Jackson 145 Name 145 General Character and Thickness 145 Distribution 146 Deposition and Relation to Underlying Formations 147 'Subdivisions 148 Correlation with other Areas 148 Details of Section 149 Brazos and Grimes Counties .' 149 Madisonville Branch 153 Trinity River Section 157 I. & G. N. Ry. Section 163 Groveton Section 165 H. E. & W. T. Ry. Section 170 Manning Section 176 Caddell's Section 177 Santa Fe Ry. Section 180 Sabine River Section 181 Volcanlcs. . 182 Close of Eocene 183 Salt Pans CHAPTER VIII — Introduction 185 Oligocene 185 Deposition and Character 186 Corrigan '. 187 General Character and Relations 188 Area and Thickness 189 Sabine River Section 189 Santa Fe Ry. Section ' 192 Angelina River Section 194 T. & N. O. R. R. Section 195 Neches River Section 197 H. E. & W. T. Ry. Section 200 Kickapoo Creek Section 207 Trinity River, Section 210 I. & G. N. Ry. Section 213 Brazos River Section 218 vi Table of Contents Page CHAPTER IX — Neocene 219 Introduction 219 Fleming 221 General Statement 221 Sabine River Section 222 Burkeville Section 223 Santa Fe Ry. Section 225 T. & N. O. R. R. Section 226 H. E. & W. T. Ry. Section 22Y Trinity River Section 229 Cold Springs Section , 230 I & G. N. Ry. Section 233 Grimes County Section 235 Brazos River Section 238 Oakville 238 General Statement 238 Brazos River Section 238 Lapara 243 General Statement 243 Lagarto 244 General Statement 244 Lafayette 246 Character and Deposition 246 Details of Section 248 Santa Pe Ry. Section 250 Angelina-Neches Section 251 T. & N. O. R. R. Section 253 H. E. & W. T. Ry. Section 255 I. & G. N. Ry. Section 259 West of Trinity 259' Close of Neocene 260 CHAPTER X — Quaternary 264 Pleistocene. ; 264 General Character •. . . .264 Angelina-Neclies 265 Trinity River 266 Beaumont Clays 269 Surface Features 272 Salines and Mounds 272 CHAPTER XI— Lignite 275 General Character 275 Methods of Utilization 276 Lignites of the Wilcox 277 Lignites of the Yegua 283^ Lignites of the Jackson 289' Table of Contents vii Page CHAPTER XII — Petroleum and Natural Gas 292 Origin 292 Occurrence 294 Cretaceous Oil and Gas 298 Eocene Oil and Gas 303 CHAPTER XIII — Salt and Gypsum 307 Salt 307 Domes 307 Salines 309 Origin of Salines 310 Mounds in Association with Salines 311 Salines of the Wilcox , 311 Salines of the Yegua 312 Salines of the Jackson 313 Salines as a source of Salt 315 Gypsum 315 CHAPTER XIV — Iron 318 Shelby County ores 322 Nacogdoches County Ores 322 Rusk County ores 323 Cherokee County ores 323 Anderson County ores 331 Henderson County ores 335 Houston County ores 336 CHAPTER XV — Clays 338 Clays of the Midway 340 Clays of the Wilcox 341 Clays of the Marine 352 Clays of the Fayette and Yegua 354 Clays of the Jackson 355 Clayp of the Fleming 357 CHAPTER XVI — Fuller's Earth, Volcanic Ash and Glass Sand. .360 Puller's Earth 360 Volcanic Ash 362 Glass Sand 365 CHAPTER XVII — Building Stone and Gravel 367 Building Stone 367 Sandstones of Marine 367 Sandstones of Fayette 369 Sandstones of Jackson , 370 Sandstones of Corrigan 373 Gravels 377 Inside J- of Back Cover LIST OF ILLUSTRATIONS Plate I Geologic Map of Texas. II Sketch Map showing distribution of forma- tions West of Navasota III Map of Iron Ore Regions, Cherokee County. IV Pendleton Bluff, showing Wilcox formation 40 V Patroon Bayou, showing Wilcox formation 49 VI 1 — Aaron's HiU, Nacogdoches, showing Marine formation 81 2 — Westmoreland Bluff, showing Yegua formation 81 VII 1 — Clay Pit, Homer, showing Fayette formation. . 145 2— Cut, HE&WT Ry., eross-hedded sands of Jackson formation 145 VIII I — White Rock Creek, volcanic ash of Jackson formation 177 2 — Volcanic Ash Bed, Jackson formation 177 IX Trinity River, contact of Jackson- C or rigan 193 X 1 — White Rock Creek, Corrigan formation 209 2 — Riverside, Corrigan formation 209 XI 1 — Jasper County Quarry, Corrigan quartzite .... 225 2 — Smith's Ferry, Fleming clays 225 XII Colmesneil, Lafayette formation 249 PREFACE. The great importance of the Tertiary beds of southeastern Texas from an economic point of view is now beginning to be realized and appreciated. During the existence of the Geo- logical Survey of Texas, 1888 to 1894, the prevailing opinion of the people of eastern Texas was that geological work might benefit western Texas but could be of little assistance to them, and this opinion had much to do with the opposition that led to the discontinuance of the survey. The passing years, how- ever, have shown the erroneous nature of this idea and have proved something of the true value of the mineral resources of the beds underlying the region. In them is stored, in the form of beds of lignite, a vast amount of material which must be our hope for fuel throughout the coast country after the present oil supply has been depleted. Associated with them are deposits of iron ores which, probably, are only second in quantity to those of the Great Lakes Region and are the equal in quality of any brown ores found anywhere. The accumulations of oil that, beginning with the Lucas well at Spindletop, have been found by the drill and have played an important part in the develop- ment of this region, are all within their sediments. The domes of the Coastal region are an integral part of them and contain possibly as large an amount of salt as is known within a like area in the world. From the known extent and thickness of beds as proved by drilling it has been estimated that there is here at least one ton of salt for every inhabitant of the earth 's surface. These domes also hold a vast amount of sulphur and they are today supplying more than 90 per cent of the sulphur produced in the United States. There are also numerous other substances of value within these formations. With this potential wealth of mineral resources now only partially developed it is essential that a careful study be made of the deposits in order that every assistance possible may be given to the development of the area. The Geological Department of the Southern Pacific Lines in Texas and Louisiana, in the course of its work on the oil con- ditions and mineral resources of the territory tributary to its 2 University of Texas Bulletin lines in southeastern Texas, has made detailed investigations of a portion of the area and the general results are deemed of suf- ficient interest to warrant publication. Upon the request of Prof. J. A. Udden, Director of the Bureau of Economic Geology of the University of Texas, the matter of such publication was taken up with the President of the Southern Pacific Lines in Texas and Louisiana, Mr. W. B. Scott, and the Chairman of the Executive Committee of the Southern Pacific Company, Mr. J. Kruttsehnitt. The request met with their approval and the accompanying "Eeport on the Geology of East Texas" has been prepared as a contribution from the Southern Pacific to the increase of knowledge of the region. To assist in the development of this region and that lying south of it, it seemed best to give briefly the character of all un- derlying beds, to combine with the reports of the geologists work- ing under the writer the observations of other workers in the same field and the broader results of his own personal investiga- tions, and to add his interpretation of them, in order that a full resume of our present knowledge of the geology and mineral re- sources might be available to those who may desire such infor- mation for the direction of future exploration and drilling. By treating the subject in this way the writer has gone some- what further into the matter than was at first contemplated. The personnel of the Geological Department of the Southern Pacific Lines, whose work has contributed to this report, is as follows : E. T. Dumble, Consulting Geologist 1897-1918. W. F. Cummins, Geologist... 1902-1918. W. Kennedy, Assistant Geologist 1902-1916. Lee Hager, Assistant Geologist 1903-1904. L. P. Garrett, Assistant Geologist 1903-1908. C. L. Baker, Assistant Geologist 1912-1913. J. R. Suman, Assistant Geologist 1912-1917. J. W. Bostick, Assistant Geologist 1916-1918. "W. "W. Kelley, Assistant Geologist 1917. E. T. D. THE GEOLOGY OF EAST TEXAS By E. T. Dumble, Consulting Geologist, Southern Pacific Company. Chapter I INTRODUCTION The special area covered by this report^ is a strip of country over 100 mjles in width lying between parallels of 30° 30' and 32° and extending from the Sabine to the Brazos or the line of the Houston & Texas Central Railway. The mapped area includes, in whole or in part, the following counties : Anderson Leon Robertson Angelina Limestone Rusk Brazos Madison Sabine Cherokee Montgomery San Augustine Freestone Nacogdoches Shelby Grimes Navarro Trinity Houston Newton Tyler Hardin Panola Walker Jasper Polk A proper presentation of its geological features, however, in- volves a consideration of a more extended region. Consequently, the report embraces more or less detail of a very considerable portion of Texas and parts of Louisiana and Arkansas. THE REGION The region is a part of the Gulf Coastal Plain. This plain is composed of sediments laid down in former extensions of what are now the waters of the Gulf of Mexico, and began with the submergence at the commencement of the Cretaceous. These deposits required longer or shorter periods for their accumu-- lation and alternated with periods in which there was little or no deposition and others when parts of the deposits already, laid down were carried away through erosive agencies and redis- ^Mss. of this report was submitted Aug. 10, 1918, published Feb. 1920. 4 University of Texas Bulletin tributed over the land or deposited in bodies of fresh water. This was brought about by the fluctuations of the levels of the land surface as compared with those of the waters of the Gulf. Deposition continued intermittently through the Cre- taceous and Tertiary to the present, with but few interrup- tions of major importance. Our present land surface is due to the gradual recession of the strand line of the Gulf, and the Plain itself does not even now terminate at the water's margin, but stretches outward to the one hundred fathom line of sea depth. That this is its true structural limit is shown by the fact that beyond this line the bottom of the sea slopes downward with great rapidity. For the most part the sediments forming this plain in eastern Texas are in beds of rather loosely compacted materials which as a whole slope gently toward the Gulf. Thus, as we travel eoast- ward, we come upon successively later and later formations, the surface exposures of which form a series of belts of varying width roughly paralleling the present shoreline. As the waters slowly receded from these various formations and they were exposed as land surfaces they were seized upon by erosive agencies and gradually sculptured into their present topographic forms. The alternations of broad bands of clays and sands with other bands of more compact sandstones and clays which extend west- ward from the Sabine are reflected in the topography by belts of comparatively level country bounded to the south by lines of hills more or less abrupt on their northern faces and dipping southward with a gentle slope to the succeeding plain. These belts are in turn dissected by the many streams crossing them and this results in a hilly or gently rolling country. Prac- tically all the elevations are directly due to erosion, and earth movements have had little effect on the present surfieial aspect of the region. While there is comparatively little evidence at the surface today to show the effects of erogenic action we do find unmis- takable evidence that there were at least three periods in which earth movements of considerable extent affected this area and that two of these were accompanied by active volcanic eruptions. Of these movements one began toward the close of the Austin The Geology of East Texas 5 Chalk deposition, a second is known in connection with the upper Eocene and the third occurred during or at the close of the Upper Pliocene. The effects of these movements are often masked by the level- lying succeeding deposits. Only a few of the volcanic necks of the Cretaceous are known and those of the Eocene are as yet undis- covered, although the ejectae which form so large a portion of the upper Eocene and Oligoeene deposits indicate that they may have been within our own borders. The area of our report includes only a portion of the Tertiary deposits of this great plain. LITERATURE There have been published numerous reports and papers, some not now accessible to the general public, which treat to some extent of the geology of this region. Eeviews of earlier pub- lications have been given by HillS Penrose^, Dumble', Veatch*, Deussen", and others. Among the publications of special interest as descriptive of this area and of the same formations in contiguous territory the following may be mentioned: The existence of lignite and iron in this region was referred to by several of the early voyagers, and in 1839 Dr. J. L. Riddell published in the American Journal of Science a description of the lignite beds on the Trinity below Hall's Bluff. B. P. Shumard in his First Report of Progress" gives briefly ^Hill, R. T., Present Condition of Knowledge of the Geology of Texas. Bull. U. S. Geol. Sur. No. 45, 1887. "Penrose, R. A. F., First Ann. Rep. Geol. Sur. Tex. 188 9. ^Dumble, E. T., Iron Ore Districts of East Texas. Second Ann. Rep. Geol. Sur. Tex. 1890. Report on Brown Coal and Lignite, 1892. Problem of the Texas Tertiary Sands, Bull. Geol. Soc. Am. Vol. 26, pp. 447-476, 1915. *Veatch, A. C, Geology and Underground Water Resources of North- ern Louisiana and Southern Arkansas. U. S. Geol. Survey Prof. Paper No. 46, 1906. 'Deussen, Alex. Geology and Underground Water-Supply of Southeastern Texas. Water-Supply Paper No. 335. 'First Report of Progress of the Geological & Agricultural Survey of Texas, 1859. 6 University of Texas Bulletin, the results of his reconnaissance of the region. He made two general sections. The first began at Sour Lake and passed through Hardin, Tyler, Jasper, Sabine, San Augustine, Nacog- doches and Eusk counties to Marshall in Harrison county. The second was from Henderson in Rusk county through Cherokee, Anderson, Freestone and Limestone counties to Waco. In this report he calls particular attention to the deposits of brown coal or lignite and iron ores and to the occurrence of petroleum at Sour Lake. Buckley'', in his Preliminary Report, gives some details of these and in his First Annual Report goes more into particulars regard- ing the various deposits of iron ores and lignites in several counties and the petroleum near Melrose in Nacogdoches county. He also mentions the oil seep in the Gulf near Sabine Pass and the oil at Sour Lake. In his Second Annual Report Buckley also refers to the lig- nites of this area. Loughridge gives a very concise statement of the geology of this region in his Report of Cotton Production in Texas in Re- ports of the Tenth Census. The first publications to deal particularly with this area were those of Penrose in the First Report of Progress and First An- nual Report of the Geological Survey of Texas. In these the broader features were mapped out clearly and a beginning was made in the work of securing detailed geological knowledge of East Texas. The general geologic section is given together with descriptions and analyses of the different deposits of iron, lignites, marl, oil, salt, etc. In the Second Annual Report of the Geological Survey of Texas the work so well begun by Penrose is continued and ex- panded. Under the general title Report on the Iron Ore Dis- tricts of East Texas there appears as comprehensive a statement of the general geology and mineral resources as was possible under the conditions existing at that time. In the Introduction 'Preliminary Report of the Geological & Agricultural Survey of Texas, 1866. First Annual Report of the Geological & Agricultural Survey of Texas, 1874. The Geology O'f East Texas 7 Dtunble gives an historical sketch of the iron industry of East Texas, a general statement regarding the topography of the iron ore districts, an adaptation of the geology as given by Penrose and his conclusions regarding the character and mode of occur- rence of iron ores. The possible fuels and their utilization are briefly treated by Birkenbine and Lerch, followed by a descrip- tion of the counties where workable iron ores were thought to occur. These reports on counties ga,ve what details of geology were obtainable but were mainly devoted to a description of the location, character and quality of the iron ores and other eco- nomic minerals. Kennedy reported on Cass, Marion, Harrison, Gregg, Morris, Wood, Upshur, Van Zandt and Henderson coun- ties; Herndon on Smith county; "Walker on Panola, Shelby. Rusk, Nacogdoches and Cherokee counties, and Dumble on An- derson and Houston counties. Accompanying the report was a map which showed the general distribution of the ores. In the Third Annual Report, published during the following year, Kennedy makes a special report on Houston county, and gives quite fully the general geological features and mineral re- sources so far as they were understood or could be determined at that time. Our later studies enable us to better classify some of the formations described by him but otherwise the report needs little change. This report is followed by a description of a general section made from Terrel to the Gulf directly across our region. This section has been the basis of much of our later work. In this description the Timber Belt beds of Penrose are divided into two members called the Lignitic and Marine and the latter is sub- divided into the basal or Mt. Selman and the upper or Cook's Mountain. Similarly the Fayette beds of Penrose are separated into three members. He defines the Luf kin or Angelina county deposits, later found to be the same as those described as the Tegua, the age of wMch was definitely fixed by the accompanying fossils. He describes the sands around Corrigan and correlates them with those called Fayette because of certain fossils found near them. He also describes the overlying clays which form so large a portion of the surface of the area mapped and gave them the name Fleming. In tlie Eeport on Brown Coal and Lignite Dumble maps and describes the lignite deposits of this area. In the Fourth Annual Eeport Kennedy makes a report on the geology of Robertson and Grimes counties and gives a general description of the various formations. Later discoveries of fossils necessitate some change in the references of these beds. During the fifth year of the work of the Geological Survey Harris was employed in the study of the large collections of Ter- tiary fossils which had been brought in by the members of the survey. The paper he prepared for publication in the Fifth Annual Report described and figured all of these forms. The drawings for this report were beautifully done and the plates made from them were very fine. Unfortunately, the State did not publish the report nor any other portion of the Fifth An- nual. Harris then selected the forms that were new and pub- lished them in the Proceedings of the Academy of Natural Sciences of Philadelphia^. A paper on the fossils from the Deep Well at Galveston was published in the Bulletin of American Pal- eontology and in the same publication he has since described and figured the marine fauna of the Midway and Wilcox formations of the entire Coastal Plain, with which he has included all forms belonging to these two formations found in our Texas region prior to publication. A similar report on the Claiborne fauna is now in process of publication. Kennedy in a paper, Iron Ores of East Texas'*, brings to- gether a good description of the iron ores of* East Texas with many analyses taken from the reports of the Survey. He also published a paper entitled The Eocene Tertiary of Texas Bast of the Brazos River^", in which he gives a more de- tailed account of the beds with sections and lists of fossils and a resume of the history as he interprets it. Hayes and Kennedy, in Oil Fields of the Texas-Louisiana Coastal Plain^^, furnish a map showing distribution of the Ter- tiary in southeast Texas and general statement of the geology followed by details of the coastal oil fields. »Proc. Phil. Ac. 1S95. 'Trans. Am. Inst. Min. Eng'., 1894. '°Proc. Acad. Nat. So. Phila. 1895. "Bulletin U. S. G. S. 212. The Geology of East Texas 9 In United States Geological Survey Bulletin No. 260 Fenne- man covers some of the same ground. In the publications of the University of Texas Mineral Sur- vey Phillips has a Bulletin which gives analyses and microscopic studies of the Coastal Oil, and another on Coal, Lignite and As- phalt Rocks, to which Brooks and B. F. Hill contributed a por- tion of the descriptive matter and Harper a valuable chapter on the analyses of Texas asphalts. Simonds in his list of Mineral Localities of Texas brings to- gether the reported localities of all East Texas minerals. Ries, in Clays of Texas", describes a number of the clays found in this region and gives analyses of them. Phillips, in connection with Worrell and Drury McN. Phillips, published as a Bulletin of the Bureau of Economic Geology "The Composition of Texas Coals and Lignites" and the use of Pro- ducer Gas in Texas, which should be of value in future utiliza- tion of the lignites of East Texas. Harris, in his work as State Geologist of Louisiana, was as- sisted by Veatch, who was studying the artesian water conditions of Louisiana and Arkansas. The examinations were extended into parts of East Texas aijd among the fossils collected at the locality four miles north of Corrigan and at one or two other localities between that point and the Sabine, as well as on that river, species were found which indicated the Jackson or Upper Eocene age of the beds. This was announced by Harris^^ with other results of these examinations. Veatch^* later also described the occurrences. To the Corrigan sands of Kennedy he applied the name Catahoula and correlated them with the "typical Grand Gulf ' ' which immediately overlies the Vieksburg and is of Oligoeene age. He also refers the Fleming beds to the Oligocene. Deussen embodies the results of his examination of this region in his report "Geology and Underground Water-Supply of Southeastern Texas '.'i^. From this report and the geological maps accompanying it, his "University of Texas Bulletin 102. "Geol. Sur. La. 1899-1902. "U. S. G. S. Prof. Paper No. 46. "U. S. Geological Survey "Water-Supply Paper No. 335. 2-ET. 10 University of Texas Bulletin understanding of the geology appears to differ somewhat from that of Veatch and Harris, and he apparently uses the names given by Veatch to cover very different series of beds from those to which they were originally applied. "While this may 'be some- what confusing, the change of name of a sand need have no effect on its water-bearing quality and the report is of very prac- tical value. Dumble, in a paper entitled "Problem of the Texas Tertiary Sands "^"j attempts to clear away as far as possible the various misunderstandings as to the ages of the several sands involved in the description of this area. He reviews the earlier work and uses that of later geologists working under his direction to give the broader features of the geology of the region. It is this view that is adopted in the following report which is therefore, in part, an expansion of the above paper, but includes many details which could not be given in it and treats the entire subject in a much broader way as it utilizes information taken from many other sources. "Dumble, Bui. Geol. Soc. Am. Vol. 26, 1915. Chapter II PRE-CEETACEOUS The entire pre-Cretaeeous history of the whole east Texas re- gion is probably that of a land area. From the beginning of geologic time until late in the Mesozoic it was a part of the ancient land mass, known as Llanoria, orig- inally of great- extent, and of which the primordial rocks of the Llano-Burnet region with their fringe of earlier Paleozoies, are now the only visible remnant east of the Pecos river. Supposedly it stretched southwestward into Mexico, connecting directly with the Columbian area of that region. It spread westward and southward an unknown distance. Branner holds that it ex- tended across the Mississippi basin to a direct connection with the Appalachian belt in Ala;bama. Shuchert^, however, con- siders the two areas as separate throughout the entire Paleozoic except in middle Cambrian and upper Silurian time. His eastern border of Llanoria is just west of the Mississippi Eiver. It probably extended over all of east Texas and Western Louisiana, reaching also into southern Arkansas. In the Texas area this land mass formed the southern and eastern boundaries of the epicontinental seas of Paleozoic, early and middle Mesozoic times, and it furnished much of the ma- terials that entered into the formations laid down in them. While no remnants of this land are known either in eastern Texas or in the Coast country, evidences of its former existence are sufficiently numerous and plain f East Texas 17 Devil's river and further west certain aberrant forms which are characteristic of the Edwards limestone throughout its extent have persisted or recur and are also found in the Washita (Georgetown) limestone. The Washita limestone, with a thickness of 80 feet at Austin, shows a separation into several members when followed north- ward. In the Red river section the Kiamitia clays form the base, succeeded by the marls and chalky limestones of the Duck Creek beds, capped by the Fort Worth limestone and these, together, show a thickness twice as great as the Georgetown limestone at Austin, which they represent. The Del Rio clay, also called the Arietina clay, from the name of its most abundant fossil, has a thickness of 80 feet at Austin and consists principally of clays with some gypsum and thin slabs of shell breccia and, at the top, thin layers of arenaceous limestone. In the Red river section the basal clays are practically missing and the Arietina is probably represented only by the Main street limestone of the Denison bed which has a thickness of 15 to 25 feet. ■The Buda limestone, with a thickness of 80 feet on the Col- orado, also gradually thins to the northward and beyond the Brazos is represented by lime marls and thin limestones. Taff", tracing these beds and using the zone of the characteristic oyster Gryphaea mucronata as the base of the Buda. found that they continued in marly form to Red river and eastward along that stream to Pottsboro and Denison. These marls were described as the Grayson marls by Cragin^ and occupy a stratigraphic po- sition above the Arietina or Del Rio and below the Woodbine, thus corresponding to the Buda further south, but whether they cover the whole of Buda time is not yet determined. The con- ditions are fully stated by HilF, who correlates the Buda, in part at least, with the Grayson marls. In the Denison region the Washita has a total thickness of some 400 feet consisting of the Preston, Fort Worth and Denison "Fourth Annual Report Geol. Sur. Tex. p. 277 et seq. ■•Colorado College Studies, 1894, p. 43. 'Twenty-first Annual Report, U. S. G. S., Vol. 6, p. 266 et seq. 18 University of Texas Bulletin formations while near Cerro Gordo, Arkansas, the entire series is represented by calcareous clays containing thin beds of lime- stone with a total thickness oJE about 250 feet which to this time has not been found susceptible of such division as is used further west. The marked difference in the character of the upper members of the Comanchean as we pass from the sediments of the deeper waters on the south into the zone of littoral deposition in the Red river region is thus clearly shown. This condition becomes even more pronounced as we go eastward into Arkansas. Another view of the age of the Buda is that "there are good reasons for believing that the Buda limestone may be repre- sented in the north by at least part of the "Woodbine formation. According to the fossil fauna in this latter formation, its age can not be far from that of the Buda limestone. ' '* "With the close of the Buda sedimentation came the end of the Lower Cretaceous and the emergence of these deposits from be- neath the sea. There was probably a gradual withdrawal of water from the land, and, as the Red river region formed for a long period the littoral zone of the formation and probably was subjected to movements of smaller range than more southern regions, it is possible that a portion of the materials now in- cluded in the "Woodbine sand, which has been supposed to mark the beginning of the Upper Cretaceous deposits, may have been laid down as shore line deposits at this time and thus mark the final stage of the Comanchean, but the stratigraphic evidence seems to indicate that, taken as a whole, the Woodbine belongs to the Upper Cretaceous. LOWER CRETACEOUS FORMATIONS OP EAST TEXAS. Colorado River Denison Texas- Louisiana Line Buda Denison Denison Washita Del Rio Port Worth Fort Worth Georgetown Preston Preston Edwards Fredericksburg Comanche Peak Goodland Goodland Walnut Clays Walnut Clays Paluxy Trinity Glen Rose Antlers Sands Trinity Travis Peak ■Bull. Univ. of Texas, No. 44, p. 65. The Geology af East Texas 19 EVENTS AT CLOSE OF COMANCHEAN While there is little evidence of deformation by faulting or folding in the Red river area at the close of the Comanchean, erosion was somewhat active and unconformities occur between the \ipper Denison beds, comprising the Mainstreet limestone and Grayson marls, and the succeeding "Woodbine. This uncon- formity is clearly shown on the south side of Cedar Mills where the Buda has been entirely removed in places and soft false- bedded sandstone of the Woodbine is in direct contact with the Arietina limestone. The basal clays of the Woodbine are present only occasionally and occur as thin wedges or lenticular masses. At other places the clays seem to lie upon the Buda blue lime- stone with perfect conformity. " While the erosion of the Lower Cretaceous of northeastern Texas was not extensive and while there may be in places ap- parent conformity between the Grayson marls and the basal elays and sands of the Woodbine in the Red river region, and the beds show but little evidence of discontinuity of deposition, the fact that there was a long interval of time between the last deposition of the Comanchean and the beginning of the Upper Cretaceous is clearly brought out in their relations as seen south of the Brazos. Here the Woodbine is absent and the Eagle Ford rests directly upon the Buda limestone and this condition con- tinues through the whole sweep of the contact between Waco and Del Rio. They appear conformable everywhere, and yet we know that between the two we had the deposition of the Woodbine. In this area since no erosive action is discernible it is probable that during the interval between the deposition of the Buda and the Eagle Ford the former must have remained very near the water level if not below its surface, since even where very long contacts are observable the two formations ap- pear to be in perfect conformity. West of the Pecos, however, in certain areas, the beds of the Comanchean were elevated a sufBcient length of time for the complete erosion of the entire Washita series and the channeling of the Edwards limestone into deep canyons. This surface was •Taff. Fourth Ann. Rept. Geol. Surv. Tex., p. 282. 20 University of Texas Bulletin again submerged during the Eagle Ford and these channels filled with its shales. We thus have a central zone in which the movement was prac- tically negligible, with very gentle movements in the northeast bringing the upper beds to the surface, ibut not so as to com- pletely destroy them, while in the west the elevation must have amounted to hundreds of feet with" consequent impetuous erosive action destroying a whole series of beds. SALT DEPOSITS The low-lying coast and shallow waters prevailing in the southern and eastern regions were very favorable for the exist- ence of sea basins from which evaporation could remove the water more rapidly than the fresh-water streams could renew it and thus precipitate both gypsum and salt. That such condi- tions existed may be reasonably inferred from the bodies of salt which are now found in connection with the Cretaceous salt domes. Thus, in the Palestine dome the salt is known to be di- rectly overlain by the Woodbine. Harris, in his section of the formations at Drake's saline in Louisiana shows the salt stock uplifting the Cretaceous limestone and overlain by it and the test well passing through the salt bed into gypsum at 2842 feet. At Grand Saline a somewhat similarly bedded condition exists. It is, therefore, probalble that all of the salt now found in these Cretaceous salt domes or islands was deposited during this in- terval. There is, however, a possibility that the salt is somewhat older. As we have seen, the Lower Cretaceous sediments of this North- eastern Texas area are comparatively thin and we know that the Trinity sands in Arkansas contain heavy beds of gypsum. It may be, therefore, that these beds of rock salt were laid down about the same time as the Trinity gypsum and it may be that these conditions continued through the greater portion of the Comanchean. At any rate it is Cretaceous. UPPER CRETACEOUS With the beginning of Upper Cretaceous time a shallow sea invaded our region and spread northward beyond Red river and The Geology of East Texas 21 westward to the Brazos. Its first sediments were the Woodbine formation which is not found further south than Waco, but extends eastward as far as Clarksville. To the eastward in Ar- kansas the "Woodbine is represented by the lower part of the Bingen sands composed of sands with bituminous, laminated clays containing leaf impressions and lignite beds. WOODBINE The Woodbine formation is one of great economic value. On the western border it furnishes a supply of artesian water over a considerable area and in its eastern extension it is the principal oil-bearing horizon of Northeastern Texas and Western Louis- iana. In the Red river region the Woodbine has at its base the varia- ble bed of impure clay, which is often lignitic and sandy, called the Basal clay, overlain by an extensive deposit of brown and yellow ferruginous sandstone carrying siliceous ironstone, known as the Dexter sands. These are capped by a series of lignitic sandy clays with numerous moUuscan fossils called the Timber Creek or Lewisville beds^". In east Texas the formation has an. estimated thickness of 600 to 800 feet. (EAGLE FORD As the waters became deeper the shales of the Eagle Ford were deposited. On the Colorado it consists of bluish and gray shales and arenaceous laminated shales. In the northern part of the State it is composed of blue and black laminated bitu- minous clays with large septaria, sands, clays, shales and thin layers of brown sandstone. The clays grade upward into brown sandy ferruginous glauconitic beds interlaminated with beds of clay. These clays carry fossiliferous concretionary masses of limestone and the brown sands, which are locally fossiliferous, are called the Blossom sand^^- While these distinctions hold for the Texas exposures of these beds the outcrops in Arkansas are not similarly separable and "Fourth Ann. Rept. Geol. Surv. Tex. pp. 2 93-294. "Gordon, Water-Supply Paper 276, p. 19. 22 , University of Texas Bulletin the Eagle Ford as a whole is represented by the upper portion of the Bingen sand which thus covers the entire time interval of both Woodbine and Eagle Ford in that locality. Of all the upper Cretaceous deposits, the Eagle Ford seems to be the most uniform and constant. While it has its near shore phase of sands and clays, the bulk of the deposits are limy shales, and these not only encircle the Edwards plateau, but stretch southward into Mexico for 200 miles or more, where they attain a very much greater thickness than anything we know in Texas. Furthermore, Ihese deposits, wherever we find them, whether sands or clays or lime, are usually shales and carry a characteristic fauna throughout their entire extent. AUSTIN CHALK During the deposition of the Chalk, which followed, a condi- tion of clearer waters existed, and in the main the Chalk is fairly free from materials derived from the land area and is an almost pure chalk, but there are localities where the clays were carried out and deposited with it, occasionally to such an extent as to make it merely a chalky marl. In its relation to the underlying Eagle Ford it shows the same variations noted in other similar contacts. In the central part of the State the division is quite clearly defined and the line of separation can be fairly well made out even on the Kio Grande east of Del Rio. Further west the distinction is not so readily apparent, and in the region of the Big Bend of the Rio Grande^ where the Eagle Ford takes on a more marly character and the Austin chalk is marly also, it is difficult to find the dividing line without careful examination of the fossils. This is noticeable also in northeastern Texas where it loses its chalky character and from Sherman eastward it assumes more and more the character 'of a clay marl or marly clay in its basal portion, the chalk condition persisting only in the uppermost portion of the beds, and, finally, in southwestern Arkansas giving way entirely to marl. In eastern Texas the lower marly member is known as the Brownstown marl while the chalk is called the Annona and is one of the best known lithologie units of the Caddo oil-field. In the south hundreds of feet of this formation are made up The Geology of East Texas 23 of ehalk and chalky marls, tout toward the end of the period more and more terrigenous sediments were incorporated with these, and the upper margin of the Chalk is not so well defined, since at most places it grades almost imperceptibly into the base of the overlying Taylor marls, there becoming simply limy clays with some sand, and 'finally passing into the more sandy beds of the Navarro which form the top of our upper Cretaceous series in the eastern field. TAYIiOB AND NAVARRO On the Colorado the Taylor consists of a calcareous clay or marl which, while yellow in fresh exposures, weathers to a black waxy ' soil. In its lower portion it is ' comparatively free from sand, but higher in the section the sand increases and quantities of glauconite occur. The fauna also changes with the appearance of the glauconitie and to this portion of the beds the name Na- varro is applied. In Arkansas the Taylor and Navarro are represented by three members known in ascending order as the Marlbrook marl, Naeatosh sand and Arkadelphia clay with a total thickness of 1200 feet. Throughout the Caddo field the Naeatosh sand is a well recognized horizon and furnishes a considerable quantity of gas. While these are the latest sediments of the Cretaceous found in east Texas they are not as late as others occurring in the Big Bend region of the Rio Grande or along that river southeast of Eagle Pass. If these latest beds were ever laid down in east Texas they disappeared in the general erosion at the close of the Cretaceous. UPPER CRETACEOUS FORMATIONS OF EAST TEXAS. Colorado River Denison Texas- Louslsana Line Navarro Webberville Navarro Arkadelphia Naeatosh. Taylor Taylor Taylor Mho-lbrook Austin Austin .Austin Annona Brownstown Eagle Ford Eagle Ford Eagle Ford Lewisville Bing^n Sand Woodbine Dexter 24 University of Texas Bulletin EVENTS AT CLOSE OF CRETACEOUS The close of the Cretaceous in North America was marked by the Laramide elevation which was the main factor in the forma- tion of the Eccky mountains. This great movement not only affected the rock materials of the trans-Pecos region but was ap- parently active also in .eastern Texas. The beginning of this movement is generally placed in uppermost Cretaceous time if not at its close. The Texas area contains proof not only of sim- ilar movement at this time but also of a Cretaceous movement which took place earlier, beginning during the deposition of the Austin Chalk and either, continuing to, o'r being renewed at, the end of the Mesozoic. As affecting the Texas region this earlier movement began by the formation of a folded area starting in northern Mexico about the 102d meridian and striking south southeast. The evidence is clear that this elevation took place during the period of the Austin Chalk. It has been called the Sabinas barrier and formed the beginning of the Rio Grande embayment. To the north of this barrier the succeeding Gulf Coast Cretaceous sedi- ments are largely clays and sands and include the coal beds of the Rio Grande region, while to the south we find only a great thickness of blue and black shales. The beds of the embayment area are frequently very fossiliferous "while the shale beds are practically destitute of fossils. The Sabinas movement, or that which formed the Sabinas barrier was marked in Texas by Pilot Knob and other volcanoes northeast and southwest of Austin which were active during the close of the Chalk deposits and the beginning of the Taylor Marls as is proven by the ash and other ejectse from them which are interstratified with and included in these deposits. Some of these volcanoes were certainly submarine. At the close of the Cretaceous, that is, during the time of the Laramide elevation proper, this movement was intensified in the Mexican region and resulted in raising a land barrier which is now marked by the disconnected. ranges and groups of hills that form the eastern border of the valley lying at the foot of the Mexican Cordilleras. This barrier, known as the Tamaulipas range, reaches the present Gulf shore in the vicinity of Tordo Tke Oeology of East Texas 25 bay some 50 miles north of Tampico and forms the southern limit and boundary of the Gulf Coast Eocene. The Eocene de- posits found west and south of the barrier are not only of dif- ferent character, but the fossils they contain are unlike those to the north. During the Laramide movement in the western Trans-Pecos region the country was folded and faulted with the production of mountain ranges which are our representatives of the Eocky Mountain chain. There was also great volcanic activity in this region which probably continued well into the Eocene. Outside this region, however,' the movement was gentler and the entire Texan area was raised along its northern and western borders giving the surface as a whole a gentle tilt in a southeastwardly direction toward the Gulf of Mexico. It is possible that some igneous activity accompanied this movement, especially in south- west Texas. FOLDS AND DOMES In eastern Texas and Louisiana the effect of the movement tak- ing place at approximately the time of the Laramide elevation was the formation of folds and domes in the newly deposited ma- terials of the Cretaceous, like those in Freestone county, at Pal- estine, Drake's and Steen's salines which ha^ maintained their individual characters and now appear as inliers in the Tertiary area. So far as is now known these uplifts were not accompanied by the intrustion of basalts or other igneous rocks the only in- trusives known being stocks of salt, anhydrite and gypsum. Some idea of the extent of the uplift may be had from the conditions at the Palestine dome. The Woodbine is the surface formation fifty miles northwest of Corsieana. A well drilled at Corsicana found the base of the Woodbine at a depth of 2460 feet. This would give the base of this formation a dip of 50 feet to the mile. The Palestine dome is fifty miles southeast of Corsicana and the Woodbine in place of being 5.000 feet below the surface as its average dip would imply, forms a part of the surface rock. Even with a greatly decreased dip the vertical displacement of these beds at this place must have been from 2500 to 3000 feet. While a part of the present displacement is S-ET. 26 UiHversity of Texas Bulletin due to later uplifts than that at the end of the Cretaceous, these were very slight in comparison with the earlier one. The Palestine dome was unquestionably an island in the early Tertiary sea. The sediments of the Midway or earliest stage of that period are not found on it. Those of the "Wilcox occur around it and probably covered it as did the succeeding Claiborne and it is now uncovered because of the erosion of these later beds. To the north of the Palestine dome, about six miles, is the Keechi island which is, in all probability, eonneeted directly with the Palestine dome but which shows at least 1400 feet less displacement since the Navarro beds are at the surface and it is 1460 feet to the top of the Woodbine as proved by weUs drilled near it. In alignment approximately parallel to the present boundary between the Cretaceous and Tertiary and forty-five to fifty miles from it we find to the north of the Palestine-Keeehi island domes the Brooks and Steens salines in Smith county. These are domes similar to the Palestine with Cretaceous rocks at the surface. Whether these are all connected and simply represent peaks of an anticlinal or are isolated upraises is not positively known, but the ehai'acter and structure of the Midway deposits lying be- tween them and the Cretaceous border seems to favor the former view. Sabine Peninsula To this period also must be referred the formation of the Sabine Peninsula, which was first recognized by Harris and which is a very important physiographic unit of eastern Texas arid western Louisiana. It is probable that the Laramide elevation outlined this Cretaceous table-land and was the priii- cipal agent in its elevation, although later movements may have also had something to do with its present condition. On the surface this Peninsula is a belt of the Lignitic phase of the Wilcox, in places more than thirty miles in width. Ptom the Cretaceous border north of Texarkana it extends southward along the Texas-Louisiana line to Sabinetown, a distance of 130 miles. It is flanked east, west and south by bodies of Lower Claiborne. The Geology oj East Texas 27 The elevation of its surface at Texarkana is 300 feet and at Sabinetown is 200 feet, a fall of less than one foot per mile. The rocks underlying this Lignitic Peninsula, as shown by wells, comprise about 450 feet of Lignitic and 250 feet of Mid- way followed by the Northeast Texas section of the Upper Cre- taceous. The sections from north to south as made, based on drilling records, show the Upper Cretaceous beds dipping southward from Eed River at about 50 feet per mile to the vicinity of Vivian, Louisiana. Here the Sabine uplift begins which brings the Cretaceous beds up again to within 500 to 700 feet of the surface thus creating a Cretaceous plateau the southern border of which has not yet been accurately determined but is near Sabinetown, so that it has a length of about 100 miles. It is evident that the displacement at the southern end of this plateau may be even greater that that at the Palestine dome. The eastern and western borders are not definitely known, but it extends westward into Panola and Shelby counties. Basing the estimate on the top of the Annona Chalk the dip of the Cretaceous betwen Vivian and Sabinetown is 300 feet or about 3 feet per mile. A weU on the Jesse Low survey below Sabinetown encountered the Chalk at 1900 feet whUe deeper wells further south did not find it at all. West of the line between Vivian and Sabinetown a well on the Jane Thorp survey in Panola county reached the Chalk at 1315 feet, the top of the Cretaceous being put at 265 feet below the surface. Thirty miles south of this well at Flat Fork entered the Chalk at 1690 feet, the top of the Cretaceous in this well appear- ing to be at 960 feet, indicating either a thinning of the beds above the Annona or their erosion prior to the deposition of the Midway. The well records also show that the Cretaceous rocks have been folded first along northeast-southwest lines and later at right angles to this. To the east of this plateau there are a number of domes which are Cretaceous islands similar to those found west of it in the Texas area.* *For details of these domes see reports in Geol. Sur. Louisiana, 1899-1902 and Bulletin No. 7 of Louisiana Geological Survey. Chapter III TERTIARY INTRODUCTION At the close of the Upper Cretaceous the waters of the Missis- sippi embayment receded to an unknown distance southward and the former sea bottom emerged and became a land area. This land area was probably of the nature of a broad plain the flatness of which was broken by the domes, ridges and plateaus arising from the Laramide uplift. The plain itself was probably but little above the sea-level for there is no evidence of extensive erosion in the sands and clays of the Cretaceous which formed its surface. The emergence, however, was of sufficient duration to make a most complete break in the paleontological column. Every species and even many genera of mollusks which inhabited the Cretaceous sea completely disappear at the close of the Creta- ceous and we find an entirely new fauna beginning in the Ter- tiary. The same is true of the plant remains so far as they are known. With the incoming waters of the first Tertiary sea there began the deposition of the sediments which cover the whole of Eastern Texas. The Tertiary deposits of this region are sediments laid down, for the most part, in comparatively shallow water, during periods of slow and gentle oscillations. Apparently the conditions sur- rounding their deposition were not greatly different in character from those now existing along the Gulf Coast although the indi- cations are that some phases had much greater extension than at present. The first deposits are those of marine waters alternating with those of lagoons and swampy areas followed by others which were laid down by streams and wind in land areas similarly alternating with lagunal deposits. They consist principally of lightly compacted clays and sands with some limestone. Inter- bedded with or included in these are considerable amounts of gypsum, beds of lignite, deposits of oil, salt and sulphur and much ferruginous material in the form of glauconite, siderite. The Geology of East Texas 29 pyrite and limonite. The formation, as a whole, dips gently seaward at the rate of 5 to 40 feet per mile with occasional variations in direction and amount. On the basis of these differences in mode of deposition and of their fossil contents the beds have been separated into several groups. The following table gives the subdivisions of this series as it applies to eastern Texas: THE TERTIARY FORMATIONS OP EAST TEXAS Brazos: Trinity: Sabine: Lafayette ^ Lafayette Lafayette Neocene Lagarto Lapara Oakvllle Woodville Fleming Burkeville Fleming Fleming Navasota Coldsprings Oligocene Corrigan •' Onalaska • Catahoula Catahoula Jackson Manning? Caddell? Wellborn Fayette? Mianning Caddell Wellborn Manning Caddell Eocene •Claiborne Yegua Marine Carrizo Yegua Marine Queen City Yegua Marine Wilcox Lignitic Lignitic Sabine Midway Midway Midway TERTIARY SECTIONS The special region considered in this report is forested and in places densely wooded. The best opportunities for study are the 30 University of Texas Bulletin sections found along the various rivers crossing it from north to south and the cuts along the railroads which traverse it in the same direction. These rivers from east to west are the SaJbine, Angelina, Neches, Trinity, Navasota and Brazos. The railways include the Gulf, Colorado & Santa Fe, Jasper to Carthage; the Dallas Branch of the Texas & New Orleans ; The Houston, East & West Texas; the International & Great Northern; Trinity and Brazos Valley ; Madisonville Branch of International & Great Northern, and the Houston & Texas Central. In addition to the roads crossing it, the Missouri, Kansas & Texas, Cotton Belt and others give valuable sections. The sections made along these lines show clearly the general composition of the beds entering into the different formations and the changes which occur in the deposits as we pass from the eastern border to the interior of the State. EOCENE The earliest period of the Tertiary is known as the Eocene and is divided into the Midway, Wilcox, Claiborne and Jackson stages. Of these the Midway and, Claiborne are composed prin- cipally of marine deposits while the Wilcox and Jackson com- prise deposits both of marine and palustrine character, the pal- ustrine portions representing inshore deposits approximately contemporaneous with the offshore deposits of the marine por- tions, and in places interlapping with them. The Midway and Wilcox together form the Lower Eocene. The Claiborne is the Middle Eocene and the Upper Eocene has sim- ilarly only one member, .the Jackson. ftUDWAY The Midway formation, first named by Smith and Johnson from an Alabama locality, was more fully described by Harris in his report on The Tertiary Geology of Southern Arkansas in the second volume of the Annual Report of the Geological Survey of Arkansas for 1892 and in his American Bulletin of Paleontology under the title of the Midway Stage, where he has also described and figured the fossils which characterize it. These beds or parts of them had been described previously in connection with other The Geology of East Texas 31 deposits and by various authors. Deussen^ gives a fair resume of publications treating on the beds now referred to the Midway with their equivalencies as understood at this time. GE>fERAIj ChARACTEE AND THICKNESS The Midway beds are marine sediments and comprise in their area of outcrop a series of interbedded clays &nd sands usually dark bluish or black but occasionally light yellow in color, mica- ceous, frequently laminated, and sometimes gypsiferous, inter- bedded with limestones or calcareous nodules and boulders. Fossils are abundant both in the limestones and in the beds of sands and clays. In the eastern part of the State where there is no outcrop and the beds are known only from materials encountered in drilling wells these beds are found to be predominatingly clayey with glaueonite and sand in thinner layers and with thin beds of sandstone and limestone. In thickness they vary from 200 to over 400 feet. Deposition and Relation to Underlying Beds The Midway sea swept inland from the south gradually sub- merging the Cretaceous land but in our Texas area ceased its encroachment before it had reached the limits of its predecessor, the Ripley sea. It swept around the domes and ridges but its rather shallow waters, though they may have been somewhat deeper than those of the Ripley, did not engulf them all. To the northeastward in Arkansas, it reached inland entirely across the Cretaceous and its beds overlap the Bingen sand and are in direct contact with beds of Paleozoic age which underlie it. The highest beds of the Cretaceous whjch formed the sea bot- tom on which the basal Eocene or Midway deposits were laid down were of sands and clays and at no place were there any limestones at the surface. It is probable that much of the ma- terial of the Midway was directly derived from these and, there- fore, the two series of soft materials coming together frequently >Deussen, A. Water-Supply Paper No. 335, 32 University of Texas Bulletin fail to register any unconformity. Consequently, at many places where the contact has been observed there is no apparent strati- graphic break and in weathered surfaces it is at times very difficult to distinguish the two formations. As a whole, however, the Cretaceous beds are massive and the basal Tertiary are dis- tinctly stratified and this aids in separating them in the absence of fossils. While this lithologie similarity between the Upper Cretaceous and basal Eocene largely obscures it in places, there is an actual erosional unconformity between as seen in Georgia and on the Frio and Rio Grande rivers in Texas. Area op Outcrop The contact of the Midway and Cretaceous on the Brazos river, which for our present purpose we may use as our southwestern boundary, is found in a bluff in Falls county, one and one-half miles north of the line of Milam county. To the south and west of this point the beds cross the Colorado below Webberville and the Rio Grande in southern Maverick county and their final exposure in North America is found about 30 miles east of Monterey in Mexico, near Eamones, on the Pes- queria or Salinas river. Northeast of the Brazos the Midway outcrop is found in a belt stretching along the Cretaceous front in a northeasterly direction to the southwestern portion of Hopkins county, a distance of about 175 miles. In its narrowest part it is less than five miles in width but in the vicinity of "Wills Point it broadeiis out to some 15 miles. North and east of this it is covered by the Wilcox overlap until it again appears at the surface in the vicinity of Malvern, Ar- kansas, resting directly upon the Paleozoic beds and overlain by the Wilcox. It here forms a belt from one to four miles in width and extends northeastwardly by way of Little Rock to Indepen- dence county. In northeastern Texas the Midway underlies a stretch of un- dulating prairie country with interspersed patches of timber land. The timber is mostly black jack and post-oak with a few black ash and sycamore trees along the creeks. The Geology of East Texas 33 Details of Section Kennedy found the contact between Midway and the under- lying Cretaceous at only two places. At the bluff on the Brazos river in Falls county one and one- half miles above the Milam county line he found at the base a massive bed of blue clay 14 feet thick, with Baculites and other Cretaceous fossils. Eesting upon this was a bed one foot thick of blue clay which he considered transitional between the Cre- taceous and the overlying five feet of blue clay and sand break- ing into nodules and conchoidal fragments and weathering into a grayish yellow. This bed contained such caracteristic Midway fossils as ApporJiais sp., Aid. Ostrea pulaslcensis, Har. Veneri- cardia alticostata, Con. Gucullaea macrodonta "Whit, etc. The other contact appears about four miles west of Elmo, Van Zandt county, where the dark blue laminated clays of the Midway rest upon the bluish weathering yellow marls of the uppermost Cretaceous. The basal Midway clays here are thinly laminated, have occa- sional nodules of limestone and broken bivalve shells in the up- per portion. They have a thickness of 30 feet and are overlain by brownish gray sands also carrying limestone boulders. In the Brazos section, half a mile below the contact, a bluff at Blue Shoals has at the base laminated blue or black fossilifer- ous clay overlain by blue indurated clay with boulders or concre- tions of limestone containing Ostrea pnlaskensis. Harris Encli- matoceras ulriclii "White, Cucxillaea macrodonta "Whitf. Veneri- cardia alticostata, Con. and other forms. Milam bluff or Black bluff on the Milam county line is forty feet in height and composed of clays and calcareous beds, black at bottom, but yellow or greenish at top, with many fossils. Cribbs bluff further south shows the dark blue laminated clay overlain by interbedded limestones and yelow clays with many fossils. The uppermost portion of the beds in this section is seen in Smiley 's or Oyster bluff two miles north of the mouth of Pond Creek where laminated sands are interbedded with laminated clays, concretions and hard limestones, carrying such fossils as Ostrea crenuUmarginata, Pleurotoma anaconGeol. Sur. La. 1902, p. 128. 70 University of Texas Bulletin Unconformity. 3. Brownish-black lignitiferous clay, interbedded witb medium grained brownish-gray sand, and wavy- bedded and laminated lignitiferous sand and clay. The alternations are frequent. The beds contain hard local aggregations of reddish-brown ferruginous sandstone. In the upper part is laminated brown- Ish-blaok lignitiferous clay, with some layers up to 9-inches thick of dark brown lignitiferous sand con- taining patches of lignitiferous clay 6 4. Medium-grained light gray sand weathering light yellow- ish-brown, with flakes of mica forming an almost perpendicular bank at 1 ow water stage 12 Two hundred yards below the bluff 6 feet of chocolate-brown lignitiferous sand and shaly clay overlies 3 feet of coarse green- ish sand. In the upper portion of the coarse sand are thin cross- bedded layers of lignitiferous clay. Above the lignitiferous clay is 2 feet of post-Eocene ferruginous pebble conglomerate at the usual "spring line". Near the base of the chocolate-brown clay are numerous irregular-shaped clay ironstone concretions, none of which are larger than 1 foot in diameter. The beds dip to the southeastward at the rate of about 1 foot vertical to 50 feet hori- zontal, but this is perhaps not the absolute amount or direction of dip. The next exposures one-fourth mile lower down show the re- currence of hiarine conditions, the beds dipping 8% degrees South 4 degrees "West. Here six feet of chocolate brown sandy and shaly clay is overlain by very fossiliferous concretionary and oolitic greensand. One-fourth mile farther down the river, thin layers of oolitic greensand are interbedded and overlain by chocolate-brown sandy clay. The fauna carried by the greensand layers is of Cook's Mountain age. The chocolate-brown shaly clay carries irregular blotches of sulphur and limonite. About 20 feet of this clay overlies the fossiliferous greensand. The dip is southward. Lenses and poctets of greensand and small concretions are found in the clay. Ferruginous conglomerate is strewn along the banks. A well defined terrace on the west bank of the river marks the ' ' spring line ' ' at the contact of the bedrock and surficial forma- tions. TJie Geology of East Texas 71 The fossils at these two last localities are very abundant and well preserved. A little less than two miles below the mouth of Bayou Negreet there begins a great oxbow bend in the river, deflecting it tem- porarily toward Columbus nearly two miles from its general southerly course. The beds forming the banks of this bend are very fossiliferous and Veateh has given the following sections of the exposures. He states^: "Along the east and west reaci above Columbus, on the Texas bank, there are a number of outcrops of very fossiliferous Lower Claiborne. At 21 a long shelf, ten feet high, shows the following section : Feet 1. Gray and yellow sands and clays 15 2. Very dark gray fossiliferous laminated clay with lines of concretions. Contain a characteristic Lower Claiborne fauna. Among other forms Belosepia ungula, Turritella nasuta var. hou^tonia. davilithes pennosei, Cornulina aurmigera (small) 9 3. Covered 3 4. Very fossiliferous greensand. Many fossils silicified 2 5. Finely laminated bluish gray sandy clay with traces of vegetable matter 6 Dip here seems to be due south. A quarter of a mile below this outcrop, at 22, the following sec. tion is shown: Feet 1. Unexposed to top of bank 14 2. Pebble conglomerate 2 3. Laminated, dark brown clay and yellow sand, containing fossils irregularly through the whole mass. Anomia epMppoides is very common 23 Dip a little west of south. The best collecting in the Lower Claiborne occurs at 23, two miles by river, above Columbus. Feet In. 1. Gray and yellow sandy clay with small ferruginous gravel. Clayey portions weather into little pinnacles. .20 2. Bluish gray laminated clay with sand partings and oc- 'Geol. Sur. La. 1902, p. 129-130. 72 University of Texas Bulletin casional patches of sand. Marked ledge of concre- tions in upper part of bed 11 3. Dark green shell limestone weathering red. Contains many specimens of ArcavrTiomboidella 6 4. Same as 2 but much more fossiliferous 4 Dip southwest. The lower layer is filled with a great variety of beautifully pre- served Lower Claiborne forms. Columbus. The bluff at Columbus is much complicated with landslips and it is impossible to get a very satisfactory section. The following is from the best exposures: Feet 1. Fine gray sand, tinged with yellow 8 2. Pebble conglomerate 2 3. Drab clay with small concretions. 4 4. Ledge of fossiliferous dark grey limestone with PUcatula fllamnentosa, PeCtunculus idonev^, Area rhomhoidella 1 5. Light green, laminated, fossiliferous clay 20 6. Light green, laminated, fossiliferous clay with large numbers of Ostrea Johnsoni, var. and 0. falciformis 4 7. Ledge of calcareous concretions 1 8. Same as .5 3 Bluff so complicated with landslips that dip observations are un- satisfactory; dip seem to be south, a little east." The last fossiliferous exposure referred to the Marine by Veatch is found just where the oxbow is completed and the river resumes its normal southeasterly course. At this point the dip changes from West of South to Southeast and so continues. Only a short distance below, the beds referred to the Tegua (Cock- field) make their appearance with this same dip. It is, there- fore, probable that the beds at Veatch 's locality 24 are the basal Tegua rather than the uppermost Marine. The width of the surface exposure of the Marine where it is cut by the Sabine river is about four miles. The average dip of the beds throughout their exposures on the river is about S. 20° W. Taken as a whole the pre-Yegua, Lower Claiborne section found on the Sabine river differs considerably from those farther west. The Queen City beds seem to be entirely wanting. The Geology of East Texas 73 The Marine here begins with highly fossiliferous strata which give place below Bayou Negreet to lignitic beds with a small amount of iron in the form of carbonate nodules. This soon passes upward into other greensands and sands with many well preserved fossils and those form the bulk of the section. The Mt. Selman phase of beds marked by fossil casts "is not apparent, and except for the lignitic member below the middle of the section, the fossils are present in abundance from bottom to top. The iron contents are negligible, while five miles northwest, the hill at Irona gives a typical Mount Selman iron-bearing section. Going westward from the river we find on Low's creek some good exposures of the Lignitic beds capped by the greensands. At the lower wagon bridge the section shows : Carbonaceous clays and sands, most typically with thin leaves of brown, black, or dark-blue clay interbedded with medium-grained sands, brown or gray in color. Some of the sand layers are a foot or more in thickness. Sections higher up the creek show greensand marls overlain by chocolate brown sandy clay and greenish-brown clay with oolitic greensand and small calcareous concretions. These up- per beds contain fossils. The Wilcox- Claiborne contact is apparently shown on a small creek tributary to the Paloguacho on the Gaines survey. At the base are structureless drab clays, which are followed by glauconitic sands carrying some fossil casts and in turn overlain by laminated drab and chocolate colored sandy clays, carbona- ceous and gypsiferous, with partings of gray sand. In this mem- ber there occurred large concretions up to 3 feet in diameter of carbonate of iron, extremely hard and containing veins of calcite. Above this the deposits get rather more sandy and gypsum and pyrite occur abundantly, a dark blue color being imparted to the clayey sands. The thickness along the creek here is something like 30 feet. The dark blue sandy clays, which are probably Wilcox, are directly overlain by a layer of iron ore which forms the capping of several small hanging valleys and also seems to be the cause of a terrace which runs along some 20 feet above the creek. This is probably the base of the Queen City or of the Marine if the Queen City is not present. This was not deter- 74 University of Texas Bulletin mined here. Nothing excepting boulders of iron ore and sands are exposed from here to the top of the hill some 135 feet above the blue clayey sand. The Irona iron deposit is located on the top of the Claiborne escarpment which rises immediately south of this creek to a height of more than 200 feet. A large part of the slope is talus strewn and the hill is covered with a dense forest growth of oak hickory, sweet-gum and short-leaf yellow pine. The section iJ> as follows: 1. Loose sand. 2. Iron 4 ft. max. 3. Covered 135 ft. 4. Laminated iron "ore" 5. Dark green coarse, loose sand witli abundant small crystals 6. Sandy light brown clay with flaky selenite and abundant small particles of lignitiferous matter; unconsoli- dated and structureless. 7. Shaly light chocolate-brown sandy clayey with large roundish concretions of blue sphaerosiderite seamed with crystalline calcite. 8. Loose, coarse sand, some grains of which are coated, probably with silicate of iron and potassium. Weath- ers dark greenish-brown and contains casts of Ven- ericardia, Oorbula, Leda, etc. On seams and cracks the color is dark reddish brown. 9. Light gray sand clay. SANTA FE RAILWAY SECTION The section made along the Santa Fe Railway gives a more complete series of the T)eds. The Queen City is present at Duff, as has been stated. South of Duff the Mount Selman is first seen in the form of brown sands, in which thin beds of laminated ores are interstratified. Few exposures were seen between this . point and Bland Lake, where there occurs a loose sand of light buff color which is also found at Arenosa 10 miles northwest of San Augustine. This is practically the top of the Mount Selman in this section, as just south of it, the fossiliferous greensands begin, and these continue at the surface to a point between Mile Posts 118 and 117, some four miles south of San Augustine. South of this the exposures along the railroad are of the tran- The Geology of East Texas 75 sitional clays and sands and are unsatisfactory, The final ap- pearance of Cook's ]\Iountain greensand is at Birdwell Siding one-third mile south of -Mile Post 109. This gives the Marine beds an exposure along this line of nineteen iniles. Baker says of this section : "There are four phases of the Lower Claiborne (exclusive of the Tegua) along this line of traverse. At the base are the Queen City beds, succeeded by the iron-bearing, generally un- fosiliferous Mount Selman sands and clays. Next in upward succession comes the member of fossiliferous greensand known as Cook's Mountain, overlain by the sands and clays of the Cook 's Mountain,Yegua transition, in which there are a few thin layers of greensand. The iron-bearing Mount Selman forms the dominating ridge." SAN AUGUSTINE SECTION The details of the beds around San Augustine are of interest. The following is the section at Mile Post 121, G. C. & S. F. Ky. : 1. Dark reddish-brown altered greensand with concretionary limonit'j, both in laminated and concentric forms. The iron in concretionary form is found mainly at the con- tact of the weathered a.nd unweathered greensand. Small calcareous concretions are rather abundant in the altered zone. Although these occur in the top of the less altered zone they are comparatively rare there, suggesting their possible origin from the gypsum of the unaltered greensands. This grades downward into: 2 Greensand — green clay containing secondary selenite in crys- tals often as large as half an inch. Abundant dark green oolites; all smaller in diameter than the head of a pin, also small fakes of "clastic" selenite. The oolites in the weathered specimens are set in a whitish matrix, probably calcareous. The green clay is in very small balls and nodules which in unweathered specimens form a matrix for the oolites 10 ft. 3. Light gray, fine grained, thin-bedded, sandy clay with small flakes of selenite and a minor percentage of oolitic greensand in small, very dark green concretions. Poorly preserved fossils 3 ft. The material taken from a well close at hand is a grayish-blue, 76 University of Texas Bulletin rather light oolitic greensand clay with fossils. This represents less altered material than any mentioned in the foregoing sec- tion. There is 15 feet of the clayey greensand exposed in a cut 200 yards north of Mile Post 121. This exhibits various degrees of alteration. It has gypsum and calcareous concretions. The limonite is mainly distributed in thin, irrregularly-laminated layers runnng at various angles with the horizontal, but nearer the horizontal than the vertical. The greensand exhibits a very imper,fect shaly lamination. The superficial, unconsolidated, weathered product is dark brownish-green below, becoming a dark reddish-brown above. The gravel in the surficial layer is mainly composed of irregular angular pieces of ferruginous con- cretions. Section on creek joining Ayish Bayou just north of railroad station -. 1. Greensand. 2. Chocolate-brown clay withi thin flakes of selenite 7 ft. 3. Greensand with thin local layers of iron ore 15 ft. Dodecahedrons and cubes of pyrite were found in the top of member No. 1 of the above section. At the falls on this creek member No. 1 is a dark green, very clayey greensand. The clay balls have a fibrous structure like slickensides. Member No. 2 is on the whole rather badly frac- tured and when wet has a bluish-green color. Detailed section at San Augustine from the top of the hill at Little Rock to the G. C. & S. F. Railway north of the station : 1. Very ferruginous reddish-brown Lafayette locally with pebbles or with hard coarse sandstone cemented by limonite. Unconformity : 2. Beach or reef bed of hard silicified and calcified greensand marl containing Gcutella, Ostrea, Pecten and large gas- teropods. This layer forms a ledge at the first Baptist Church, around the top of the circum-valley of White Rock and elsewhere on the top of the hill. Layer ap- pears to be almost entirely made up of comminuted shells 10 ft. TJie Geology of East Texas 77 3. Altered greensand with local ferruginous layers 24 ft. 4. Altered greensand with small calcareous nodules. Horn corals, yenericardia, Cortula, and other fossils 5 ft. 5. Thinly and irregularly laminated ferruginous layers with interbedded greensand lenses. Two feet below the top is a thin, harder concretionary layer 7 ft. 6. "Shelly" layered fossiliferous greensand with slickensides SVz ft. 7. Thinly-laminated, shaly, chocolate-brown sandy clay, sul- phurous and limonitic, with thin black carbonaceous lenses, flakes of selenite, and crystals of pyrite. Clay, stickier and less sandy than lower, varying from light bluish-gray and light chocolate to rusty in color. Upper layer is fine and bluish-black in color like material seen in the well on the upper Nacogdoches road 5 miles west of San Augustine. At the contact of this clay with the overlying greensand are falls on all three creeks of this vicinity 9% ft. 8., Thinly, and irregularly, laminated limonitic layers with small lenses of greensand 4 ft. 9. Altered oolitic greensand clay, dark green below, dark brown above with Gortnla and Yenericardia. Has nodular limonite coated greensand clay ironstone ait base. Mas- sive, jointed, with slickensides common along joint planes, slickensides coated a dark purplish color 9 ft. 3 in. 10. Layer of ferrufginous concretions, non-continuous, with con- centric structure of shells of iimonite around the outside with a. hard compact brown center, perhaps of iron car- bonate, dotted with oolites of greensand. Averages about 6 in. 11. Altered clayey greensand like (9). Fosillferous 4 ft. These beds are exceedingly fossiliferotis and are notable for the number of echinoderms they contain in comparison with beds of similar age at other localities. The Cook's Mountain around San Augustine is unconforma- bly overlain by dark reddish-brown sandy and clayey alluvium containing many small angular fragments of iron oxide. Some of this is Lafayette, some is residual from Lafayette, and an- other portion is either residual from the Cook's Mountain or is recent alluvium. These accumulate to a thickness at least as great as 15 feet. The beds of the Cook's Mountain dip very slightly southward and have a total thickness of 100 feet or more. The road from San Augustine to Nacogdoches runs over the 78 University of Texas Bulletin Cook's Mountain beds and there are numerous localities where fossils are found in abundance. H. E. & W. T. RAILWAY SECTION The line of the Houston, East & West Texas Railway does not afford as good exposures of the Mount Selman and Cook's Moun- tain as are found either east or west of it. The contact of the Lignitic and Claiborne is near Fitze, the first station south of Garrison, where deep cuts on the ridge expose red cross-bedded sand with some ledges of ferruginous material. This does not appear to belong to the Queen City, but to the Mount Selman. A mile south of this the greensands come in and are seen in the cuts between that point and Nacogdoches. The scarp which usually marks the line between the Mount Selman and Cook's Mountain does not appear in this section and the section does not show any dividing line. In the lower lands, along the lower slopes of the hills, and in the stream valleys in the vicinity of Nacogdoches and south, east and west of that town the surface rock is f ossiliferous greensand marl. Where unaltered, the greensand marl shows various shades of green in color and contains an abudant fauna of gas- teropods, lamellibranchs, corals, echinoids, cephalopods, and shark's teeth. The shark's teeth belong to the genvis Sipiecodus. A single species of the eephalopod, Belosepia, was found at several localities. About seventy-five species were found in all, fifty of which were collected from one locality. Much of the fresh greensand has a finely oolitic texture. Ferruginous con- cretions occur abundantly in the greensand. Where unaltered these concretions are composed of sphaerosiderite. The iron in the greensand oxidizes readilj^, imparting to the altered green- sands various shades of brown and brownish-red. In the altered greensands the fossils are in the form of easts, but when the rock is fresh the original shells are preserved. Nodules of clay are locally abundant in the greensand member. The strata of this member are thinly bedded and locally vary much in degree of consolidation, the concretionary portions being very hard and compact while the greater part of the formation is comparatively friable. The Geology of East Texas 79 NACOGDOCHES BEDS On Aaron's Hill, on El Camino del Rey, 200 yards west of Houston, East & West Texas Railway passenger station at Nae- ogdoehes, the following section is exposed: Nacogdoclies : 1. Mottled sandy clay, brick-red to bluish-gray, weathers under grass roots to buff sand 6 % ft. 2. Unconsolidated but finely laminated fine-grained sand, flesh colored to chocolate, unfossiliferous. Contains small ag- gregations of limonite, cross and wavy bedding very notice- able in upper part 17 ft. 3 in. Unconformity with difference of 3 feet in verticality along the irreg- ular line of contact. Cook's Mountain: 3. Alternating layers of argillaceous sandstone and arenaceous clay (both are "greensand marl") thin bedded for most part. Weathers rusty brown in outcrop, greenish in color when fresh. Contains fossil casts and varies in degrees of compactness. Contains much material resembling oolite or rolled small clay balls varying in size up to 1-10 inch diameter 22 ft. 5 in. 4. Dark drab, arenaceous, clayey greensand with abundant fossil casts, weathering to earthy-brown, and seamed by thin bands of earthy yellow limonite 2 ft. 8 in. 5. Very friable light green greensand, weathering to brownish or reddish-brown 2 ft. 6. Dark green arenaceous and clayey greensand, dark-purple in color, with fossil casts. Very oclitic 1 ft 6 in. 7. Better indurated, dark green sandstone, alternating with pur- ple with much iron carbonate and many casts of shells 2 ft. 5 in. 8. Dark bluish, clayey, greensand, thinly laminated and con- taining many fossil remains. 3 feet from base is a bed of oyster shells 2 inches thick. Alters to a reddish-brown ferruginous surface rock 6 % ft. At Orton's Hill on El Camino del Rey one mile east of the last described locality and jnst east of the wagon bridge over Lanana creek, the following is the section : Nacogdoches: 1. Sand mottled in places, but mainly reddish-brown in color, with some cress-bedding. 35 feet above the base Is a layer 80 University of Texas Bulletin of medium-coarse, and for the most part angular, con- glomerate with boulders up to 6-inches in diameter. The smaller particles are much better rounded than the larger. The pebbles are ferruginous sandstone. They may not all be detrital, but some may be concretions in the bed.... 45 ft. Cook's Mountain: 2. Fine-grained sand, less consolidated than in (1), bluish-white when fresh; where altered, exhibiting various shades of yellow and brown, depending on the percentage and form of the iron contained. Upper 30 feet structureless, lower 10 feet rather finely laminated 40 ft. 3. Finely laminated, fine, unconsolidated sand, with nodules of clay, chocolate brown and greenish-gray to black in color. . 6 ft. 4 Greensand marl, thin-bedded, friable, with abundant fossil casts, oolitic structure, with layers containing nodular iron. Mainly clayey, but with a minor amount of sand which increases in percentage towards the top. The least altered rock is a dark bluish-green, where most altered and nearest the surface it is rusty yellowish-brown 28 ft. There is no unconformity apparent in tlie Orton's Hill sec- tion, but the angular conglomerate in the upper member is noticeable. The above sections have been selected as typical. They also indicate that the clay and sand Eocene member is both conformable and unconformable on the underlying greensand and that there are layers of greensand containing characteristic fossils interbedded with the clay and sand Eocene member. In the harder ferruginous beds and nodules of this transition mem- ber casts of Claiborne fossils are found. Since no fossils or greensand have been found in this region in the lithologically very different lower Yegua, it is .judged most logical to group the sand and clay Eocene member in the Marine as an upper and shallower water phase. In places it rests on the Marine greensands with an irregular contact ; in other localities the member appears to rest with con- formity on the Marine. The sand and clay member exhibits much cross-bedding and frequent alternation of sand, clay, shale and gravel. The individual beds are not persistent, but notably lenticular. These structural characteristics and the relatively clastic composition of the deposits, point to a shallow- insr of the site of sedimentation after the epoch of greensand University of Texas Bulletin No. 1869 Plate VI. Fig. 1. MARINE FORMATION. Exposure on Aaron's Hill, near Nacogdoches. Fig. 2. YEGUA FORMATION. Westmoreland Bluff, Trinity County. The Geology of East Texas 81 deposition and the coming on of littoral, estuarine and partly terrestrial conditions. This sand and clay member is considered, therefore, as distinct frrom the light-colored gypsiferous beds of the Yegua, although the sand and clay member is, in places, gypsiferous. It is regarded as a distinct lithologic unit, consti- tuting the end of a cycle of Marine deposition, and to distinguish it the name of Nacogdoches is suggested for it. The occurrences noted above are outliers capping the Cook's Mountain. The greensands of the Cook's Mountain are found to the south as far as Climax, where the transitional beds between the Cook's Mountain and Yegua begin. These Nacogdoches beds occupy nearly seven miles of the section passing under the more massive clays of the Yegua near Davidson. A cutting on the Houston, Bast & West Texas Railway 100 feet north of Culvert 129A and 150 yards north of Mile Post 128, 11/4 miles south of Climax siding, southern Nacogdoches county, is interesting. There are two unconformities shown in this one section, the one between the Nacogdoches and the partially consolidated post- Yegua surficial member and one in which the Lafayette overlies with marked discordance both the Nacogdoches and the post- Yegua partially consolidated surficial member. In the base of the section is exposed some 35 feet of Nacog- doches sands and clays thinly laminated, dipping 10 degrees to the southeast. The Nacogdoches is here mainly a thinly lam- inated medium-fine light gray sand carrying small broken flakes of selenite. The sand is interbedded with thin layers of blue- gray clay of a thickness of from 1/32 inch to 2 inches. There are also some layers of limonitie stained sands and sandstone varying in thickness from the neighborhood of 1/32 inch to about 8 inches. Some of these layers are cemented into a medium-hard sandstone by limonite. Among the plants collected from this locality,' Berry identified a new species of Citrophyllmn. The upturned edges of the tilted Nacogdoches sti-ata are bevelled off to a horizontal plane and unconformably overlain, by horizontally bedded red and light gray sands and sandy clay partially consolidated, which exhibit mottling in lenticular 82 ■ Umversity of Texas Bulletin laj^ers rather than in the irregular blotches more characteristic of .the Lafayette. In composition it is mainly medium-grained sand with a considerable proportion of clay, containing tiny flakes of selenite. On freshly broken surfaces the color of the reddish portions is seen to be pink or old rose. About 10 feet of this member is exposed at the top of the cut. On the south this entire thickness is cut off by an angular unconformity, the plane of which dips a"bout 40° to the southward. The exact relationship of this member is not known. Overlying this plane of unconformity is uiicousolidated and structureless material which belongs to the Lafayette, varying in texture from medium-grained clayey sand through coarse grit to medium-coarse conglomerate; in color, from whole patches which are dark red or light gray, to irregular mottling in blotches of these two colors; in structure, from absolutely structureless to an imperfect sorting in layers of finer and coarser pebbles, the layers of which are not always horizontal, while the conglomerate exists in small to large irregular bunches ; in composition, from clay to quartz with some flakes of selenite, and to conglomerate mainly of subangular or rounded ferruginous pebbles with a few well-rounded quartz pebbles; and in induration, from loose unconsolidated sands to ferrugi- nous cemented, fairly hard conglomerate with most of the sand exhibiting on the surface a casehardening which gives it a noticeably solid appearance. Some of the material has very contorted laminae, thin layers of red and white being inter- spersed. Where it overlies the Nacogdoches next above the irregular contact, it includes small pieces of thinly-laminated Nacogdoches shales, with their bedding or lamination planes running in every direction and angle. The Nacogdoches beds are well shown in the exposures along streams flowing southward into the Angelina river in Nacog- doches county and in some of the river bluffs. They also appear in the lower reaches in the tributaries on the south side of the river. Atove the interbedded greensands, carbonaceous and gypsif- erous clays already described, the following beds were foand TTie Geology of East Texas 83 in Durazno or Wills creek, whicli rises east of Lufkin and flows northward into the Angelina. Above the higher beds of greensand found on this creek comes, first, a structureless, massive sand weathering on the surface to a light buff, but underneath the surface of a light brownish-gray. The sand contains black and brown plant frag- ments and is at least 12 feet in thickness. Higher up the creek and higher stratigraphically the next rock exposed is fine sand, alternating in thin layers of dark brown and gray, about 1/16 inch in thickness and containing plant fragments. A thickness of 8 feet is exposed. The next exposure gives the following section : 1. Laminated and shaly light brown sand. 2. Light brown, massive, medium-fine sand 1ft. 3. Sandy clay, light chocolat"? brown 1 2.3 ft- 4. Laminated light gray-brown sand with thin non-continuous streaks of dark chocolate-brown. Blotches of yellow sul- phur. Plant fragments 1 % ft. 5. Brown clay 2 in. 6. Laminated brcwn layers limonite-stained and cemented .... 1 in. 7. Light brown finely laminated fine sand with dark brown seams and plant fragments % ft. 8. Very thinly laminated light grayish-blue fine sand containing thin layers of dark brown and chocolate-brown. Contains plant fragments, has wavy laminations, and weathers brown on surface 4 ft. The next higher exposure consists of : 1. Drab laminated sand with limonite-stained seams 6 ft. 2. Brown laminated sand with plant remains 3 ft. 3. Chocolate-brown sand with black plant fragments and yellow blotches of sulphur. The upper foot gives way along bedding planes to dark Mue-gray sandy clay 2% ft. Above this then, is 5 feet of laminated, fine to medium, drab sand with thin seams stained brown with limonite and contain- inw selenite flakes and brown plant fragments. The sand con- tains a considerable proportion of clay. The next exposure shows 4 feet of gray to brown sand with yellow sulphur and brown plant remains, while the highest exposure examined in this creek gives 7 feet of. coarse loose 84 University of Texas Bulletin sand, light gray when unweathered, but light yellow when weathered. The sand contain flakes of selenite up to 1/16 inch in long dimension. Similarly, on the west of the railroad a creek on the northern boundary of Angelina county, tributary to the Angelina river, gives the following sections going up-stream : Lowest section exposed gives : 1 . Covered with surflclal material 15 ft. 2. .Alternating layers of light-brown sand and light-gray sandy clay. The sand layers relatively and absoUuely increase in thickness toward the top until they are 2 to 3 inches in thickness 10 ft . .3. Gray medium-grained sand inter-bedded with thin layers of chocolate-brown clay and with thin layers of limonite. hardened sand. The percentage of clay gradually in- creases toward the top. Where the sand and clay come in contact the sand is stained brown with a thin film of limonite 10 ft. 4. Chocolate-brown clay with small fragmentary remains 2 ft. 5. Same as (3) but without hardened sand layers 22 ft. The bedding planes are wavy and the beds correspond very well with those overlying the f ossilif erous greensands at Aaron 's and Orton's hills, Nacogdoches. About 2 miles up-stream there is an exposure of 15 to 20 feet of thinly-bedded alternating sand and clay. At the base the clay is very dark brown, almost black, with very thin layers of gray sand separating the clay layers. In the middle portion of the section chocolate-brown clay predominates, while toward the top 2 inch beds of chocolate-brown clay alternate with layers of the same thickness of light gray or light brown sand. The basal member here corresponds to the strata found at the base of Tre- wiek's Bluff, 21^ miles east of the Texas & New Orleans Railroad bridge across the Angelina river, and to the beds lying above the greensand on Orton's and Aaron's hills, Nacogdoches, and to those found on Procella and Mill creeks, respectively, northwest and northeast of Lufkin, Angelina county. One of the best sections of the upper Nacogdoches found is that of the next exposure about 100 yards up-stream from that last noted. There is here a perpendicular bank 60 feet in height. Tke Geology of East Texas 85 The lower 40 feet is made up of thin alternating layers of light gray to light brown sand and chocolate-brown clay. The upper 20 feet is mainly a light brownish buff loose sand. The laminated sand layers in the lower part of the section exhibit wavy laminae. The upper 20 feet is also thinly bedded, especially in its middle portion. The upper 20 feet differs in reality very little from the lower 40. It has a larger percentage of light brown sand an an occasional thin layer of chocolate clay. Mill creek north of Lufkin repeats the section even more in detail. The lower horizon exposed on Mill creek has thin-bedded alter- nating sands and clays containing carbonized material at base and thin seams of very impure lignite. The dip is from 5 degrees to 7 degrees to the southward. The sand varies in color from gray-blue through brownish-gray to 'reddish-brown, depending on the amount and state of the contained iron. One exposure shows 8 feet of finely laminated brownish-gray sands seamed with yel- low limonite stains and containing thin films and blotches of carbonized leaves. One hundred yards farther upstream thinly laminated, alternating dark brown clay and light brown sand layers are exposed. Fourteen feet above the base of the section is a layer varying from a knife edge to 6 inches in thickness, con- taining carbonized fragments of plant remains which are also found in the strata above and below. The individual layers are at the maximum not much more than an inch in thickness and most of them are about % inch thick. The beds lie practically horizontal and are cut by a normal fault of 10 inches vertical displacement. This is followed by a section giving 3 feet of blue-gray clay at the base succeeded by 6 feet of very carbonaceous brown sandy laminated clay, in turn succeeded by 3 feet of laminated fine sand stained with limonite and sulphur, and containing brown plant fragments. The brown clay middle member is in places so carbonaceous as to exhibit a very thin seam of brown coal. The next exposure shows at the base 2% feet of blue gray clayey sand, overlain by 8 feet of thinly laminated gray-brown crossbedded sand, having at base 4 feet of alternating laminated sand and layers containing thin bands of alternating sand and black carbonaceous matter from 2 to 6 inches in thickness and 86 University of Texas Bulletin separated by layers of the laminated sand several times their own thickness. The next section has a thickness of 15 feet. The lower 3 feet is mainly chocolate-brown shale, but inter-bedded with thin sand layers. The upper 12 feet is mainly sand with streaks and blotches of brown carbonaceous matter. Above this, in next sec- tion, 12 ft. of light blue laminated sands containing brown blotches of carbonaceous matter. In upward succession in the next exposure comes 4 feet of soft, chocolate brown, loose sand with carbonaceous matter, and streaks and blo'tches of sulphur. It is overlain by 4 feet of light gray sticky clay. The next exposure upstream is probably the base of the Yegua. From the sections given it will be apparent that the marine conditions of the earlier Nacogdoches gave way slowly to the palustrine. The transition beds between the two formations show some alternation of conditions with, however, on the whole, a gradual shallowing of water at the site of deposition, passing from the typical marine conditions with the greensand. faeies through shallower water, lagunal, and estuarial conditions with the carbonaceous and lignitic sand and clay faeies into littoral or true terrestrial conditions in the light buffi gypsiferous sands and clays containing the great abundance of silieified wood. The exact line separating the Marine .from the Yegua is some- what difficult to draw on this account. We have drawn it here as at the type locality, where the more massive gypsiferous clays begin. Here these clays come in above the highest fossiliferous beds of the Nacogdoches (which contain remains of both marine animals and plants) and in place of the abundant marine fauna characterizing the typical Yegua we have found between the Sabine and Trinity only occasional nests of poorly preserved forms. THE ST. LOUIS & SOUTH^VESTEKN SECTION This was the line of Kennedy's section as published in the Third Annual Report of the Texas Geological Survey^. The Mount Selman section as given by him is as follows: "Third Ann. Rept. Geol. Sur. Tex., p. 53. The Geology of East Texas 87 1. Gray surface sand : 10 ft. 2. Brown sand, ferruginous pebbles and iron ore 15 ft. 3. Mottled sand 10 ft. 4. Brownish-yellow sand 4 ft. 5. Brownish-yellow sandstone 10 ft. 6. Alternate strata of laminated iron ore and brown sand, the ore generally from twO' to ten inches and the sand from one to twiO' feet thick 8 ft. 7. Dark green sand containing casts of small bivalve shells.. 5ft. 8. White clayey sand .' 1 ft. 9. Dark green, nearly black, sand containing thin seams of fer- ruginous material near top, and also- containing small fish teeth and Venericardia planicosta and SpJiaerella antipro- ducta in very small numbers 12 ft. 10. Brown sand • 10 ft. 11. White sand 10 ft. 12. Alternate strata of brown sand and laminated iron ore, ore generally wavy and not more than two to six inches with sand from one to two feet thick 20 ft. 13. Pale-blue and brown clay mottled in places and laminated in others 15 ft. 14. Alternate strata of glauconitic brown sand and iron ore, the ore generally irregularly deposited, laminated and silicious and not exceeding six inches to one foot, the sand from six inches to two feet thick 55 ft. 15. Brown sand forming surface at Bullard, altered greensand changing to yellow a few feet underground 40 ft. 16. Dark green sand containing a few fossil shells and flsh teeth 24 ft. 17. Lignite or "black dirt" containing leaves 2 ft. 18. Dark lignitic clay 5 ft. Nos. 17 and 18 of this section belong to the Lignitie beds. This is generalized from the many sections made between Bul- lard and Jacksonville and brings out in some measure the ex- tremely ferruginous character of this portion of the Marine. This is further shov?n in the section three miles north of Rusk, as given by Penrose^. This section also includes the lignitic member of the Mount Selman, which is apparently near the same position in the section as that seen on the Sabine river. At the top we have beds belonging to the Cook's Mountain series. The section is as follows : ■ First Ann. Rept. Geo). Surv. Tex. p. 31. 88 University of Texas Bulletin 1. Gray and buff sands 8 ft. 2. Hard brown sandstone 1 to 3 in. 3. Brown resinous laminated hematite 1 to 3 ft. 4. Altered fossiliferous greensand 30 ft. 5. Gray clay, stained by iron in places 5 ft. 6. Dark gray sand, with glauconite specks arid rusty pyrites, giving rise to many ferruginous springs 20 ft. 7. Gray and chocolate clays, ferruginous in places 35 ft. 8. Interbedded seams of gray and chocolate clay and fosslllfer- ons glauconite marl, sometimes indurated and partly altered; nodules and lenses of clay ironstone 40 ft. 9. Gray clay, with seams of sand, and some clay ironstone. ... 5 ft. 10. Interstratifled gray and chocolate clay 5 ft. 11. Lignite 1 ft. 12. Chocolate clay '. 1 to 1% ft. 13. Lignite 1 ft 14. Chocolate clay "ft. 15. Interbedded chocolate clay and small seams of lignite, 1-8 to 1-2 inch thick, at base of section. The upper portion of the Cook's Mountain is well shown in Kennedy's Alto section: This section embraces a series of greensands and altered glau- conitic sands and sandstones lying close to the top of the "Cook's Mountain" beds. The section combines the whole of the green- sand deposits from Alto, 8 or 10 miles eastward, to the edge of the Angelina river "bottom lands", and the whole, or the greater portion, of the section may also be taken as representative of the structure of the country from Alto southwestward to the Neches. The section shows: 1. Gray sand 5 to 20 ft. 2. Ferruginous sandstone 1 ft. 3. Iron pyrites and lignite 1/, to 1 ft. 4. Laminated iron ore and brown sand 10 to 15 ft. 5. Brown and yellowish-brown altered glauconitic sand with streaks and nodules of calcareous matter and containing Terebra houstonia Harris, n. sp., Pleurotoma (Surcula) gaW Conrad, Ostrea sellaeformis, var. divaricata Lea, Pinna, sp., Trigonarca pulchra Gabb, P^eudoUva vetusta Con., Volutilithes petrosa Con., Latirus vvoorei Gabb, Cor- tula texana Harris, Corbula aldricM, var. smithvlllensis Harris, Dentalium minutistriatum Gabb, Venericardia planicosta Lam., Venericardia rotunda Lea, Glavilitfies The Geology of East Texas 89 regexa Harris, n. sp., Plws texana Gabb var., Distortrix sep- temdentata Gabb, Solarium, acutum, var. meekanum Gabb, TerelieUum, Calyptrophorus velatus Con., Mesalia claibor- nensis Con., Anomia ephippioides Gabb, Cerithium vinctum Whitf., Pecten claibornensis Conrad, Pecten deshayesii Lea, PUcatula fllamentosa, Con., Cytherea texacola Harris, Crassatella texana Heilp., Turriteila nasuta Gabb, and many of these in profusion." 6 ft. 6. Yellowish-brown and grayish-brown, often grayish-green, in- durated greensands containing most of the fossils found in No. 5 and an additional fauna of Pleurotoma (Drillia) nodocarinata Gabb, Yolutilithes petrosa var. indenta Con- rad, Cariceila sWbangulata var. cherokeensis Harris, Cas- sidaria hrevicostata Aid., Pholadomya claiiornensis Aid., Byssoarca cucuUoides Con., Martesia texana Harris, n. sp., Dentalium, minutistriatum var. dum'bjei, n. var., Natica newtonensis Aid., Natica limula var., Rimella texana, var. plana, new var., Cancellaria panones Harris, n. sp., Clavili- thes {Papillina) dumosa, var. trapaquara Harris, G. hume- rosa, var. texana Harris, Cassidaria irevicosta Aid., Turri- teila dutexta Harris, Scutella caput-sinensis Heilpr., and fish teeth ... > 20 ft. 7. Greensands with casts of fossils 6 ft. 8. Brown altered glauconitic sandstone with casts of fossils . . 30 ft. 9. Greensand with fish teeth and Conns saniridens Con., Anonfvia ephippioides Gabb, Byssoarca cucuUoides Con., Trigonarca pulchra Gabb, Tolutilithes petrosa Con., Vol- utilithes precursor Dall, and others belonging to Nos. 5 and 6 8 ft. These beds are at the surface until covered by the Nacogdoches some three miles north of Wells. The transition beds continue along this line to one mile south of Pollock, where the massive clays of the Yegua are found. TRINITY RIVER SECTION The exposures along Trinity river and its tributaries west of the International & Great Northern Eailway are very numerous and characteristic. The Wilcox-Marine contat't crosses the river in the vieinitv 'The lists of invertebrate fossils given in this and succeeding sections of the Claiborne are based on Harris' Mss. Catalogue of Tertiary Fos- sils made in 1893 and now at the University of Texas, and have not had the benefit cf his later revision. 7-ET. ■90 University of Texas Bulletin of tlie north line of Leon county. A series of bluffs on ther east bank of the river give the following sections : Wooier's Bluff: — This bluff is on the Thompson headright about four miles above the mouth of Elkhart creek, and is prob- ably ten to twelve miles below the Wilcox-Marine contact. The Mount Selman beds are here found to be unfossiliferous, al- though the higher grounds lying some distance away from the river show brown sandstones and altered greensands with a few fossils. The section at the bluff appears to be more of a lignitic nature toward the base. 1. Brown and yellowish-brown sand 10 to 15 ft. 2. Clay ironstone 1 to 3 in. 3. Dark gray micaceous clay, weathering brown on outside. .. .20 ft. 4. Clay ironstone 1 to 2 in. 5. Dark blue 'or bluish-black micaceous clayey sand 2 to 6 ft. Hall's Bluff: — On the Murehison headright just below mouth of Elkhart creek: 1. Gravel and sand 25 to 30 ft. 2. Fossiliferous sandstone containing Ostrea sellaeformis, var. divaricata Lea. CeritMum vinctum Whitf., and casts of others 4 ft. 3. Red sandstone 10 ft. 4. Yellowish-white sand 2 ft. 5. Brown clay with gypsum crystals 6 in. 6. Yellowish-white sand 5 ft. 7. Irregular stratum of clay ironstone boulders 8 in. 8. Dark greensand, weathering brown, containing fish teeth, but no invertebrates 6 ft. 9. Brown sand 4 ft. Brookfield's Bluff :— A bluff a little south of west from Crock- ett, on the Brookfield headright, three miles below the mouth of Hurricane bayou: 1. structureless greenish drab clays containing white calcareous nodules up to one inch in diameter. Contains 5 feet from base a 3-inch sandy layer that is packed with gasteropod and lamellibranch remains. Also near the top there is a layer of fossiliferous indurated greensand containing oysters, etc. This clay weathers out to brown and black soil and underlies the post-oak country encountered for TJie Geology of East Texas 91 some ways back from the bluff on the road to Porter Springs. 2. Concretionary limestone layer of yellow to buff color exhibit- ing the cone.in-cone structure very well 1 ft. 3. Structureless drab and yellowish brown clay 25 ft. 4. Laminated chocolate shaly clays with intercalated layers of yellowish brown sand; contains at the top a 3-inch layer of concretionary clay ironstone 20 ft. 5. Brown sandstone in heavy bed 10 ft. 6. Clay ironstone 1 ft. 7. Laminated dark blue sand and light gray clays with iron pyrites 8 ft. 8. Lignite 2 in. 9. Same as No. 7 5 ft. 10. Thin seam of ferruginous sandstone 6 in. 11. Same as No-. 7, getting darker in lower portion of the beds and covered with a yellowish efflorescence of sulphur. Water issuing from these beds is sulphurous and the springs show considerable quantities of hydrogen sulphide to level of river 15 ft. No. (1) is probably the lowest member of the Cook's Mountaiij and the fossiliferous beds beginning at this locality are mucli more prominent farther down the river. This would give the Mount Salman beds an outcrop on the river of at least twenty miles. The small amount of iron in these sections compared with those east is very noticeable. Alabama Bluff: — This bluff is about six miles below Brook- fields in an air-line. It was originally considered to mark the top of the Marine beds on the river, but we find overlying it a broad expanse of the Nacogdoches, so that it is now regarded as the top of the Cook's Mountain only: 1. Fossiliferous greenish-blue clay 4 ft. 2. Greensand altered to a brownish-yellow sand with thin strata of ferruginous material interstratified and contain- ing Tolvula conradiana Gabb, Conns sauridens Conrad, Pleurotoma (.Surcula) gabdi Con., PI. (Cochlespira) en- gonata Con., PI. {Swrcula) moorei Gabb, PI. (DrUHa) nodocarinata Gabb, PI. -sp., AnciUa {OUvula) staminea Con., Anomia epMppioides Gabb, PHcatula fllamentosa Con., Trigonaroa pulchra Gabb, T. coriuloides Con., Leda hous- tonio Harris PseudoUva vetusta Con. var., YolutiUthes pe- 92 University of Texas Bulletin trosa Oon., Caricella demissa, var. texana Gabb, Turricula (Conow.itra) texana Harris, T. polita Gabb, Latirus moorei Gabb, Cortula alabamensis Lea, Gadulus subcoarcuatus Gabb, Fusus mortoni, var. mortoriopsis Gabb, Glavilithes penrosei Heilprin, Phos texana Gabb, Distortrix septemden- tata Gabb, Gassidaria planotecta Aid., Solarium tellastria- tum Con., Natica arata Gabb, N. limula Con., Mesalia clai- iornensls Con., Turritella nasuta Con., Spirorhis leptostoma Swain, TuriinoUa pharetra Lea 5 to 6 3. Ferruginous sandstone with iron ore 1 to 2 4. Green sand and ferruginous material same as No. 2, and containing same fossils with addition of Pleurotoma heiU priniana Harris, Ostrea sellaeformis, var. divaricata Lea, Pinna sp., Byssoarca cuculloides Con., Lapparia pac- tilis, var. moorea»KS Gabb, yenericardia planioosta Lam., Grasatella texana Harris, Cytherea texacola Harris, Glav- ilithes (PapilUno) dumosa, var. trapagtiara Harris Natica sp., Turritella nasuta var. houstonia Harris, Belosepia ungula Gabb, Eriphyla trapaquara Harris 4 ft. cook's mountain section Cook 's Mountain, a hill about two miles west of Crockett, rises 460 feet above sea-level and shows a more or less precipitous face on every side. Its face, however, is marked by a series of benches, and Kennedy made the following section on the eastern side from Milam branch to top of mountain: 1. Brown ferruginous sandstone with occasional casts of a small bivalve 10 ft. 2. Yellow-colored cross-bedded altered glauconitic sand 40 ft. 3. Brown sand and sandstone with occasional seams of fer- 5. Iron ore 1 ft. 6. Brown sand containing BuUmella kellogii Gabb, Terelira texagyra var. Harris, T. houstonia HaiTis, n. sp., Conus sauridens, Con., Pleurotoma (Surcula) gaiM Con., PI. (GocUlespira) engonata Con., PI. (Drillia) nodocarinata Gabb., PI. {Drillia) texana var. pleboides Harris, PI. {Maiir {jelia) infans var., PI. sp., lAncilla (Olivula) staminea Con., Ostrea alabamensis Lea., 0. sellaeformis var.' divari- cata Lea, Anomda epMppioides Gabb., Plicatula fllamentosa Con., Avicula sp.. Pinna sp., Pseudoliva vetusta Con. var.. yolutilithes petrosa Con., V. petrosa, var. indenta Con., y. precursor Dall var., Garicella sWb-angulata var. cTierofceen- sis Harris, Lapparia pactilis var. mooreana Gabb., Latirus moorei Gabb., Gornulina armigera Con., Gorhula alatamen- The Geology of East Texas ' 93 sis Lea, Yenericwrdia planicosta, Lam., Gytherea texacola Harris, Glavilithes regexa Harris, n. sp., Phos texana Gabb. var., Distortrix septemdentata Gabb., Scala, Natica arata Gabb., N. limula var., Sigaretus decUvis Oon., Calyptrop- horus veiatus Con., Turritella nasuta var. houstonia, Harris, T. nasuta Gabb., Belosepia ungula Gabb., and the corals Occulina Heilpr., TurMnolia pharetra Lea., Trochos- milia mortoni Gabb and Horn, and Endopachys maclurii Lea. A number of fisb teeth also occur in this bed 15 ft. This description is amplified by Suman in his section along Navarro road from point in creek bottom, approximately one mile east of Cook's Mountain, to top of mountain, the creek bot- tom being about 160 feet below top of mountain : 1. Creek bottom. Red sandy alluvial clay 7 ft. 2. Light bluish gray or drab massive sticky clay containing aggregations of small gypsum crystals. Covered at sur- face by mottled dark red and light gray sandy clay until the upper 1 ft. containing gravel. Also contains one foot below the surface rounded concentric limonitic concretions up to 2 feet in diameter 8 ft. 3. Dark purplish brown finely laminated clayey shale. Is gyp- siferous and carbonaceous. Contains partings of yellowish brown sand, and one sand layer 3-inches thick was noted. In one place there is a sand dike about four feet deep in the clayey shale 15 ft. 6 in. 4. Mottled material. Maximum exposures of about 10 ft. along road. Is covered by ferruginous and quartzitic gravel along surface in places. Is mainly a mottled reddish brown and gray sandy clay 50 ft. 5. Pine sand, gray when unweathered, but stained reddish on surface. Is cross-bedded and gypsiterous and contains layers of laminated gray shaly clay and laminated iron ore. Shaly clay layers are from few inches to 1 foot thick. The bedding planes are for the most part wavy, and len- ticular sand layers are noticeable. The sands are locally laminated with limcnitic layers and chocolate colored clay layers are to be noted. Ferruginous seams are notice- able along joint planes. The gypsum occurs as small flakes of selenite 1-32" in diameter and less. Mottled towaird top 26 ft. 3 in. 6. Ferruginous dark red sandy clay. Contains some laminated gray and brown clayey layers 19 ft. 7. About one half of this member consists of a coarse-grained, dark red, very ferruginous, slightly gypsiferous, friable 94 University of Texas Bulletin sandstone. Concretionary and pisolitic ferruginous ma- terial in places witli warts up to 2 inches in diameter. These layers of sandstone are up to 1 foot in thickness, and are interbedded with a cross or wavy irregularly thin- bedded sandy clay which is alternately streaked gray and reddish brown in thin streaks. The sandstone which has a yellowish green or yellowish brown color when freshly broken forms the flat rocky surface of Coiok's Mountain. At the northwestern rim of the mountain a medium- grained, dark brown sandstone containing casts of lamellibranohs in abundance is found. It is massive but may, in all probability, be the equivalent of the member above described which occurs on the southern rim 35 ft. 8. Covering the flat top of Cook's Mountain is a thin veneer of gravel made up of quartzose and granitic well rounded pebbles of even grain and averaging 1% inch in diameter. To the south of Cook's Mountain and Alabama bluff the Cook's Mountain beds are succeeded by the Nacogdoches, which extends along the river to the vicinity of Robbing Ferry east of the Leon-Madison county line, where it is finally overlain by the Yegua. Prom beds of the Nacogdoches on Cane creek, five mUes south- west of Crockett, Berry identified the following species of plants: Cladasporites fasciculatus Berry Cuprusinoyglon dawsonl Penh. The last appearance of the fossiliferous Marine beds on the Trinity is near the mouth of Boggy creek in southeastern Leon and in northeastern Madison counties. WHEELOCK AND VICINITY Among the more noted fossil localities of the Cook's Moun- tain are those around Wheeloek in Robertson county. The fossils described by Gabb were obtained from Cedar creek near Wheeloek. In the list of species described by that writer we find Belosepia ungula Gabb, Mwex (Odontopolys) compsorhytis Gabb, Fusus mortonopsis Gabb, Neptunea entero- gramma Gabb, Pleurotoma, Turris kellogii Gabb, T. texana Gabb, T. retifera Gabb, T. nodocarinata Gabb, EucTieilodon reticulata Gabb, Scohinella, crassiplicata Gabb, S. leviplicata Gabb, Dis- TJie Geology of East Texas 95 tortrix septemdentata Gabb, Phos texana Gabb, Psendoliva fusi- formis Con. mss., P. linosa Con., mss., P. carineta Con. mss., P. perspectiva Con. mss., Gastridium vetustum Con., Agaronia punctulifera Gabb, Fasciolaria moorei Gabb, Cymiiola texana Gabb, M^ra mooreana Gabb, M. erctMs Gabb, JBrafo semenoides Gabb, Neverita arata Gabb, Monoptygma crassiplica Con. mss., Architect onica meekana Gabb, Spirorbis leptostoma Swain, Tur- ritella nasuta Gabb, Dentalium minutistriatum Gabb, Ditrupa subcoarcuata Gabb, Bulla kellogii Gabb, Volvula conradiama G&hh,Corbula texana Gabb, Cibota mississippiensis Con., Anomia epMppioides Gabb^. The whole, or nearly the whole, of these species were obtained by the Texas Survey during the course of the work in that region, and several others have been added to the above list. The section shown on Cedar creek and in the immediate vi- cinity is as follows: 1. Brown prairie sandy soil with occasional blocks or frag- . s ments of ferruginous sandstone containing great quantities of Plicatula filamentosa. Gabb, and SpirorMs leptostoma Swain • 5-15 ft. 2. Brown altered greensand and clay 4 ft. 3. Thin seam of ferruginous sandstone 1ft. Nos. 2 and 3 contain quite an extensive fauna comprising Actaeon punctatus Lea, Bulimella kellogii GaJbb, Terebra Jious- tonia n. sp., Harris, Conits suaridens Conrad, Pleurotoma {Sur- cula) gabbi Con., PI., PI — , PI. {Cochlespira) engonata Gabb, PI. bella Con., PI. (S'urcula) moorei var., Gabb, PI. {Drillia) nodocarinata Gabb, PI. terebriformis Mr., n. sp., Pi. {Drillia) texacona Harris, PI. (Borsonia) plenta Harris, Cancellaria tor- tiplica Con., Ancilla {Olivula) staminea Con., Pseudoliva ve- tusta, var. pica, P. vetusta Con., var. fusiformis Lea, Ostrea ala- bamensis Lea, 0. sellaeformis, var. divaricata Lea, Anomia eph- ippoides Gabb, Plicatula filamentosa Conrad-, Byssoarca cucul- loides Con., Trigonarca pulcJira Gabb, T. corbuloides Con., Nu- cula magnifica Con., Leda opulenta Con., Yoldia claibomensis Conrad, Marginella semen Lea, Volutilithes petrosa Con., V. pre- ' Journal Acad, of Nat. Sci. of Phlla., Second Series, Vol. 4, pp. 376-389 and plates 67 and 69. 96 University of Texas Bulletin cursor Dall, V. dalli Harris, n. sp., Turricula polita GaJbb, Lat- ins moorei Gabb, Gornulina armigera Gabb, Petropsis conradi Dana, Corbula aldricM, var. smithvillensis HarriS; C. texana Gabb, C. alabamensis Lea, Dentalium minutistriatum Gabb, Deru- talium minutistriatum Gabb, var. dumblei, n. var., Venericardia planicosta Lam. Ci/therea tomadonis Harris, G. bastropensis Harris, Fusus mortoni var. mortonopsis Gabb, PJios texana Gabb, var., Distortrix septemdentata Gabb, Tuba antiquata, var. texana n. var., Solarium, scrobiculatum Con., S. vespertinMm Gabb, Natica arata Gabb, N. limula Con., N. semilunata, var. janthinops n. vax. Sigaretm inconstans Aid., S. declivis Con., Pyrula {Fusofi- cula) penita Con. var., Mesalia daibornensis Con., Turritella nasuta Gabb, T. dumblei flarri^ n. sp., Aturia near zic-zac. Belosepia ungula Gabb, Flabellum sp., Twrbinolia pharetra Lea and LunuUtes sp. 4. Pale to purplish-pink clay found 200 yards farther down Cedar Creek than No. 3. Very few fossils found in this bed 4 to 6 ft. 5. Dark grayish-green sand containing, in addition t O' the greater number of the fossils found in No. 2, the following: Pleurotoma childreni, var. Mtota Harris, Cancellaria pan- ones, var. junipera Harris, Cancellaria gemmata Con., Yol- utiUthes petrosa, var. indenta Con., Gadulus sui-coarcuatus Gabb, Ghrysodomus enterogramma Gabb and Solarium acutum, var. meehanum Gabb 6. Green sand with laminae of clay containing nearly the same fauna as in Nos. 3 and o with Aotaeon punctatus Lea and PI. retifera Gabb\ additional 4 to 6 ft. 7. Dark brown and purplish-brown sand and clay, laminated with fossils in sand, to bed of creek 2 ft. The next section west of this is on Campbell's Creek, near Dunn's ranch and about six miles west of Wheelock. This shows : 1 1. Black soil 2 to 4 ft. 2. Brown sand with calcareous material 4 to 8 ft. 3. Ferruginous brown sandstone and sands, altered greensands with Conus sauridens Con., Pleurotoma iSurcula) gaWi Con., PI., (Drillia) nodocarinata Gabb, PI. (Borsonia) ' Harris Mss. Tlie Geology of East Texas 97 plenta Harris, Ancilla {OUvula) staminea Con., Ostrea sellaeformis, var. divaricata Lea, Anomia ephippioides Gabb, Nuoula magnifica Con., Pseudoliva vetusta Con., var., P. v&tusta, var. fusiformis Lea, Yolutilithes petrosa, var. indenta Oon., T. precursor Dall, Latirus moorei Gabb, Cor- iula texana Gabb, Venericardia planicosta Lam., Fusus mortoni, var. mortonopsis Gabb, Pftos iesawi Gabb, var. Distortrix septemdentata Gabb, Sigaretus decUvis Con., Mesalia claihomensis Con., Turritella nasuta Gabb, Twr- ritella, dum'blei Harris n. sp., Belosepia ungula Gabb 4 tt. 4. Black laminated clay, enclosing Conus samridens Con., Pleu- rotoma (Surcula). galiiii Con., PI. phildreni, var. Mtota Harris, PI. {Drillia) nodooarinata Gabb, PJ. (Borsonia) plenta Harris, Ostrea sellaeformis var. divaricata Lea, Pseudoliva vetusta Con. var., Yolutilithes petrosa Con., Latirus moorei Gabb, venericardia planicosta Lam., Cy- therea tornadonis Harris, Chrysodonvus entero gramma Gabb and Natioa arata Gabb 2 ft. 5. Indurated greensand with Occulina, Turhinolia pharetra and Endopacliys maclurei corals and in addition to the fossils found in No. 4 Ancilla ancillops Heilpr., Byssoarea cucul- loides Con., Pseudoliva vetusta var. fusiformis Lea, Volto- tilithes precursor Dall., Cornulina armigera Con., Goriula aldrichi, var. smithvillensis Harris, G. texana Gabb, Den- talium, minutistriatum Gabb, Fusus mortoni, var. morton- opsis Gabb, Phos texana Gabb, Distortrix septemdentata Nabb, Solarium scrotiiculatum Con., S. acutum, var. meck- anum Gabb, Pyrula (Fusoficula) texana Aid., Mesalia clai. tornensis Con., Turritella nasuita Gabbi 1ft. 6. Laminated fossiliferous blue clay 10 ft. 7. Alternate strata of yellowish sand and blue clay, clay 6-inches and sand from 4 to 8 inches thick 4 ft. 8. Brown sand 1 % ft- BRAZOS RIVEE SECTION. The Brazos river section of the Marine begins two miles south of Calvert blufif, but the lower beds are largely obscured by the river deposits. A section at the International Eailway bridge across the Brazos river shows: ' Harris Mss. 98 University of Texas Bulletin 1. Yellow sandy clay, with nodules of lime ,20 ft. 2. Brown sandstone, interstratified witli brown sand 4 to 6 ft. 3. Dark green, almost black, micaceous unfossiliferous sand.. 5ft. 4. Thinly laminated dark green sand 6 ft. 5. Irregular belt of ferruginous sandstone Vz to 1 ft. 6. Dark green, almost black, sand, to water 3 ft. From this point to CoUard's Ferry the exposures are unsatis- factory and no fossiliferous beds were found. The blujff at CoUard's ferry extends nearly a mile along the river and is twenty to twenty-five feet high. The section is : 1. Brown sand 10 ft. 2. Indurated brown altered greensand 8 in. 3. Brownish-green altered greensand 4 to 6 ft. 4. Grayish-green sand 10 to 15 ft. Nos. . 3 and 4 of the section contain Pleurotoma (Surcula) gabbi Con., PI. childreni Lea, var. bitota Harris, Cancellari'a minuta Harris, Oliuella bonibylis, var. burlesonia Harris n. var., Ostrea sellaeformis var. divaricata Lea, Plicatula filamentosa Conrad, Pecen desJiaye'sii Lea, Pinna sp., Byssoarca cucullovdes Conrad, Leda opulenta Con., Pseudoliva vetusta Con., variety Volutilithes petrosa, var. indenta Con., Lapparia pactilis, var. mooreana Gabb, Latins moorei Gabb, Corbula aldrichi, var. smithvillensis Harris, Dentalium minutistiratum Gabb, D. min- utistriatwm, var. dumblei Harris n. Ya.r.,V enericardia rotunda Lea V. alticosta, var. perantiqua Con., V. planicosta Lam., Cy- therea sp., C. texacola Harris, C. bastropensis Harris, Clavilithes {Papillina) dumosa, var., trapaquara Harris, Fusus mortoni, ver. mortonopsis Gabb, Clavilithes penrosei Heilprin, C. hume- rosa, var. texana Harris, Pleurotoma (ClathureUa) fannae Har- ris, n. sp.. Solarium scrobiculatum Con., S. alveatum Con., Natica ^emilunata, var. jantkinops Harris n. var., JV. newtonensis Aid., Sigaretus declivis Con., Pyrula {FusoflcuLa) penita Con. var. Bimella texana Harris, n. sp., R. texana, var. plana Harris n. var., CalyptropTiorus velatus Conrad, Turritella, sp., Belosepia ungula Gabb, TrocMta, sp. and coral Turbinolia pJiaretra Leo. 5. Dark blue laminated clay .- 6 to 8 ft. 6. Brown coal in river 4 ft_ The Geology of East Texas 99 At Niblett's shoals, two miles and a half below. Collard's we find twelve to fourteen feet of lignitie shales, sands and lignites lying beneath twenty feet of river loam. Moseley's Ferry is an historic place in the Texas Tertiaries. It was visited by Dr. Ferdinand Roemer in 1847 and described in his book on Texas. He speaks of it as "consisting of alter- nate strata of brown ferruginous sandstones and of dark colored plastic clays, both teeming with fossils". The bluff here extends along the river a distance of about 1,500 feet and is from 25 to 30 feet high. With the exception of the upper 15 feet of brown sand it is fossiliferous throughout. The fossils are very well preserved, exceedingly plentiful and easily obtained. The dip of the beds as shown in this bluff is between 50 and 55 feet per mile, but it may be said that throughout this region as well as other portions of the older Eocene reliable dips are very hard to oibtain. Section at Moseley's Ferry, Brazos River: 1. Brownish yellow surface loam 15 ft. 2. Thin stratum of fossiliferous iron ore in boulder form.... Bin. 3. Blue laminated fossiliferous clay 3 ft. 4. Fossiliferous iron ore, running under the river about 100 yards below the ferry 2 ft. Nos. 2, 3 and 4 contain an extensive fauna, comprising Levi- fusus trabeatoides Harris, n. sp., Conus sauridens Con., in great numbers, Pleurotoma (Surcula) gabbi Con., PI. {Gochlespira) engonata Con., PI., (DrUUa) nodocarinata Gabb, PI. terehri- formis Mr., PI. (Borsonia) plentaHarris, Ostrea sellaeformis Yax. divaricata Lea, Anomia ephippioides Gabb, Byssoarca cuculloides Lea, Pseudoliva vetusta var. Yolutilifhes petrosa Con., Volutili- thes precursor Dall., Turricula polita Gabb, Latirm moorei Gabb, Corbida texana Gabb, Dentalium minutisMattim Gabb, Denta- lium minutistratum var. dumblei new variety, Venericardia planicosta Lam., Cyt-lveria texacola Harris, Cyfheria tornadonis Harris, Chrysodomus enterogramma Gabb, Phos texana Gabb, var., Distortrix septemdentafa Gabb, Tuba antiqiiata var., tex- ana new var.. Solarium acutum var. Meekanum Gabb, Sigaretus declivis Con., Mesalia daibornensis Con., Tivrritella nasuta Con., 100 University of Texas Bulletin T. dumblei Harris, n. sp., Pyrula {Fusoficula) texana Aid., and several corals. 5. Laminated fossiliferous blue clay containing Conus sauridens Con., Pleurotoma (Swrcula) galMi Con., PI. (Cochlespira) engonata Con., PI. {Borsonia) plenta Harris, PI. (Hurcula) moorei var. Levifusus trabeatoides Harris n. ap., Ancilla (OUvula) staminea Con., PseudoUva vetusta var., Voluti- lithes petrosa Con., Dentalium minutistriatum Gabb, Ven- erioardia planioosta Lam., Leda opulenta Con., Cytherea texacola Harris, Distortrix septemdentata Gabb, Mesalia claiiomensis Con., Turritella nasuta Fabb and Belosepia ungula Gabb 6 ft. 6. Fossiliferous iron ore 2 ft. 7. Altered fossiliferous greensand found at north end of bluff. 10 ft. 8. Fossiliferous iron ore ^ ft. Nos. 6, 7 and 8 contain Conus sauridens Con., Pleuroioma iSurcula) gabbii Con., PZ. {Drillia) nodocarinata Gabb, PL {Bor- sonia) plenta Harris, Levifusns trabeatoides Harris n. sp., Ano- mia epiiippioides Gabb, PseudoUva vetusta Con. var., Latirus moorei Gabb, Venericardia planicosta Lam., Distortrix septem- dentata Gabb, Turritella dumblei Harris n. sp., Byssoarca cucul- loides Con., Solarium acutum, var., msekanum Gabb. y 9. Green sand, dark green near ferry, but altering to a brown near north end, and morging into No. 7, measuring at ferry 5 ft. This bed contains Conus sauridens Con., Pleurotoma {Sur- cida) gabbi Con., Ancilla (Olivida) staminea Con., Ostrea sellae- formis, var. divaricata Lea, Anomia epJiippioides Gabb, Pseudo- Uva vetusta, Con. var., P. vetusta, var. carinata Con., Peropsis conradi Dana, Corbula texana Gabb, Venericwrdia planicosta Lam., GytJierea texacola Harris, Fusus mortoni var. mortonopsis Gabb, Phos texana Gabb, var. Distortrix septemdentata Gabb, Turritella nasuta Gabb, and Tenuiscola trapaquara Harris n. sp.,^ Turbinolia pharHra Lea, Endopachys maclurei Lea and other corals. 10. Thinly laminated blue clay, changing into brown near top, and weathering to a light blue toward the bottom; the ' Harris Mss. The Geology of East Texas 101 upper brown portion contains fossils similar to tbose in No. 9, and the lower blue contains occasional crystals of selenite 15 ft. 11. Dark, almost black, fossiliferous sandy clay 10 ft. 12. Thin seam of black clayey sand, jointed and stained brown along joints and on outside, apparently unfossiliferous. . 1ft. 13. Same as No. 11, extending into river and forming a ledge in bottom of river 14 ft. Nos. 11 and 13 contain Pleurotoma childreni Lea, var. Mtota Harris, Yoldia claibomensis Aid., Pseudoliva vetustai Con., var. Tellina mooreana Gabb, Venericardia planicosta Lam., CytJierea Imtropensis Harris, Turritella nasuta Gabb. The contact of the Marine and Yegua is seen in a bluff on the Brazos river about 500 yards south of the mouth of the -Little Brazos, with the following section.^ 1. Black soil 2 ft. 2. Brown loam with limy concretions 25 ft. 3. Fine brownish-yellow sand with occasional streaks or pockets of gravel 15 ft. 4. Gravel, with rolled cretaceous shells 2 to 4 ft. Yegua Clays: 5. Pale blue clay, unfossiliferous 5 ft. Marine beds: 6. Dark greensand showing fossils in lower portion 2 to 5 ft. 7. Dark colored laminated sandy clay containingTere&ra hous- tonia Harris; Levifusus irabeatoides Harris n. sp.; Pseu- doliva vetusta var.; Pseudoliva vetusta var. pica; P. ve- tusta, var. clausa; Trigonarca corl}Uloides; Con.; Pleuro- toma {Pleurotomella) guasites, Harris; Nucula magniflca, Con.; Leda opulenta, Con.; Latirus moorei, Gabb; Gorhula alaiamensis, Lea; Venericardia planicosta. Lam; Phos tex- ana, Gabb., var.; Natica arata, Gabb.; Natica semilunata, var. janthinops new var.; Sigaretus inconstans. Aid.; Yoldia aldricMana 4 ft. 8. Ferruginous sandstones 8 in. 9. Same as No. 7. In this section the gypseous clays are not seen nor do they appear anyvs^here in the river banks. This, however, may be expected as their position is obscured by broad, deep deposits of river alluvium which cover wide areas and form the bottom lands of the Brazos. East of the little Brazos these clays are found occupying their proper position at several places. •Fourth Annual Report Geol. Sur. of Texas, 1892. CHAPTER V. claibobne, continued: Yegua NAME The lowest member of the Fayette beds o£ Penrose was a series of clays and lignites. Their inclusion in his Fayette was due to the fact that he found no marine fossils in them, and as he had made the final fossil-bearing beds of the Marine the top of his Timber Belt beds, these were excluded. When we found Claiborne fossils in this basal clay member it became necessary to separate it from the Fayette and the Tegua formation was institiited to include the series of gypseous and salif erous clays, sands and lignites overlying the Cook's Mountain greensands and underlying the Fayette white sands and clays. THE TYPE SECTIONS The original differentiation resulted from an examination made by the writer and party in 1892, starting from Giddings and going northeastward along Elm creek, a branch of the Yegua. This creek runs in a general northeasterly direction, which is about the strike of the formations in this vicinity, and thus the course of the creek very nearly coincides with the line of parting between the Cook's Mountain and overlying Yegua clays. Owing to the numerous twists and turns of the creek the two sets of beds are found first on one side of the stream and then on the other. In some localities nothing but Marine is seen, but within a few hundred feet the Yegua is the only series exposed. Under these conditions it is extremely difficult to give any idea of the thickness or dip of the beds. The general structure of the territory, however, appears to be : 1. Thin scattering gravel in places. 2. Thinly bedded and in places laminated sands and clays with 'lignitic sands and thin streaks of lignitic material. 3. Thinly stratified blue and brown clay weathering to a brownish The Geology of East Texas 103 yellow, the layers from % to 2 inches thick. These beds show also in places laminated dark blue and pinkish colored clays carrying large blocks of selenite enclos- ing small fossil forms. 4. Thin streaks of ferruginous material, probably originally carbonate of iron. This streak lies in the form of a pave- ment of kidney shaped or ellipsoidal flattened bowlders from one to three feet in length and from six inches to one foot In thickness. These bowlders are usually concentric in structure and break in thin layers, but in some portions toward the head of the creek into square blocks. A thin streak of ferruginous or altered glauconitic sand underlies this pavement and is generally associated with it. This sand is highly fossiliferous and the fossils are usually fairly well preserved. These appear to have a strong Claiborne facies. 6. Laminated dark almost black clay. This clay breaks up Into nodules or cuboidal blocks with rounded ends and carries a considerable fauna and also a small quantity of .selenite. The fauna is usually found in nests or a large number in one place, while a considerable portion of the clay is barren. The bed is jointed and broken in places appears to be faulted. The joints are usually within a few degrees of perpendicular and are filled with thin sheets or plates of selenite. These beds are broken by a thin streak of ferruginous material similar to No. 4. 6. Pale bluish gray clay carrying fossils and gradually changing to a slightly altered glauconitic sand. This appears to be the lowest bed visible in this section and is thought to be the top of the Marine beds. Beginning near the head of the .creek and going eastward, or down the creek, the details of the section are as follows : On the northeastern corner of the Thornton Kuykendall Sur- vey the surface of the country is covered with a heavy deposit of chocolate colored clay carrying a considerable quantity of selenite crystals, and in the stream there appears a small ex- posure of hardened brownish, somewhat green-shaded, sand or soft sandstone carrying Anomia epMppoides and other Cook's Mountain fossils. The next exposure is about half a mile down the creek, where the section seen is as follows : 1. Pale blue and brown clays weathering a brownish-yellow with nodules of iron ore at base 20 ft. 104 University of Texas Bulletin 2. Thin sheet of ferruginous sandstone with dark colored greenish to black sand carrying fossils (Loc. 206),. . 6 to 8 In. 3. Thinly laminated dark-blue, almost black, clays with streaks of sulphur between the laminae. These clays carry fossils in nests, 15 ft. Coming down the creek to about a quarter of a mile west of Orell's Crossing the only deposits seen consisted of pale blue to brown clays carrying selenite. These do not appear to be more than ten to fifteen feet in thickness at exposure, but no- where could the base be seen until the locality heue mentioned was reached. The section (Loc. 205) seen at this place was: 1. Surface soil, 1 % ft. 2. Laminated or thinly stratified sands of a yellowish gray and brownish yellow color with strata from a half to two inches in thickness 8 ft. 3. Laminated dark-blue and pinkish colored clays carrying large pieces of selenite. Occasional fossils, mostly UHstortrix septemdentata and Turritella are seen, but these are generally in a poor state of preservation, .... 6 ft. 4. Thin streaks of ferruginous material lying in flat kidney shaped concretions with a half to one inch of fossiliferous sand on lower side 6 to 10 in. 5. Laminated dark blue, almost black, clays, carrying fossils in nests. This clay breaks up into cuboidal blocks or nodules with rounded ends and the bed is joined with almost perpendicular joints filled with thin sheets of selenite. It also appears to be faulted in places 5 ft. 6. Thin streaks of ferruginous material similar to No. 4 of above section, 6 in. to 1 ft. 7.- Laminated clays similar to No. 5 to creek 4 ft. A peculiarity about the fauna found in this section is the smallness of the fossils and the dwarfed appearance of the Turriiella, Pleurotoma and VolutHitkes. A short distance below Orell's Crossing the blue clays carry- ing selenite, No. 3 of above section, appear and these form the only exposure seen until a short distance above Price's Crossing, where a small exposure of ferruginous sand was seen. At this locality (Loc. 84-K) a few small corals were ob- tained. Here and there the belt of ferruginous sandstone with fossiliferous sand occurs, but in most of the exposures the The Geology of East Texas 105 fossils were poorly preserved or existed only in the form of casts. The material overlying these beds is chiefly brown fer- ruginous sand of recent age intermixed with scattering pockets of gravel. A short distance below Price's Crossing a section (Loc. 204) shows : 1. Black soil, 1 to 2 ft. 2. Thinly stratified blue and brown clay weathering to a yellowish brown, carrying considerable quantities of selenite and casts of fossils. These beds also carry a few badly decayed specimens of Distortrix septemdentata, and Turritella 15 ft. 3. Ferruginous sandstone or kidney shaped bowlders of fer- ruginous material in a concentric form, 6 in. 4. Altered fossiliferous greensand carrying a considerable fauna of Uower Caliborne fossils 4 in. 5. Pale blue laminated clays carrying some fossils, to creek,. . 5 ft. The dip of these beds appears to be S. B. 6 degrees. A bend in the creek here brings the clays and ferruginous sands to the other side of the creek, but the general section remains the same. About 100 yards further down the creek the section is clearer and the greensand at base much thicker and carries a larger fauna with much better preserved fossils. The section (Loc. 203) at this place shows: 1. Drift material, brown sand with gravel and flint pebbles. . 5 ft. 2. Laminated blue clay with brown sandy streaks. This bed carries badly decomposed Distortrix septemdentata and Turritella 10 ft. 3. Ferruginous sandstone in thin pavement and streaks 1 ft. 4. Dark green slightly altered greensand carrying well pre- served fossils of Claiborne age, 2 ft. B. Heavy bed of ferruginous sandstbne bowlders, seen, 2 ft. The course of the creek at this place turns sharply towards the southeast and al)0ut five himdred yards, farther down the gypsum-bearing cla.ys are found overlying the fossiliferous blue clays unconformably. At Evergreen Crossing a bluff of about 30 feet shows lami- nated clays and sands with some show of sulphur near the base. 8-ET. 106 University of Texas Bulletin Near the mouth of Elm creek on the Yegua river at Bluff crossing a section is as follows : 1. Gray sand soil = 1 to 2 ft. 2. Orange sandy loam, gravel on top or mixed in through it, some platy iron 5 to 8 ft. 3. Chocolate clays interbedded and laminated 6 to 8 ft. 4. Brown sand, micaceous, 1 to 1 ^ f t. 5. Lignitic clays: chocolate brown to black, with sulphur, pyrites, mica and plant remains, Nucula magniftca, Phos and Gardita planicosta, etc 6 ft. The line between the Cook's Mountain and Yegua in this, the type locality, is drawn at the base of the massive selenite- bearing clays. The Yegua here, as shown by its fauna, is, be- yond question. Lower Caliborne in age, and apparently marks a shallowing of the Cook's Mountain seas and a much broader area of lignitic deposits than is seen during the Marine. From Elm creek the Yegua continues five or six miles south- eastward to the vicinity of Nail's creek, where it is overlain by the Fayette sands and joint clays. AGE. The original collections of fossils made from these beds were studied by Harris, who determined the following forms : Ostrea sellaeformis, Lea. Plicatula filamentosa, Con. Pinna sp. Pectunculus .idoneus, Con. Trigonarca pulchra. Nucula magnifica, Con. Leda opulenta. Leda houstonia, Har. Venericardia planicosta, Lam. Chama sp. Crassatella trapaquara, Har. 0. antlstriata, Gabb.« Cytherea bastropensis, Har. Corbula alabamiensis, Lea. Dentalium minutistriatum var. dumblei, Har. Terebra texagyra var., Har. T. houstonia, Har. Conus sauridens. Con. Ringicula trapaquara, Har. Volvula minutissima, Gabb. Pleurotoma gabbi. Con. P. nodooarinata, Gabb. P. bitota var. Harris. P. texacona, Gabb. P. plenta, Har. P. crassiplicata, Gabb. P. reticulata, Gabb. Pleurotoma sp. Cancellaria gemmata, Con. C. tortiplica. Con. C. panones var. smithvillensis, Har. G. minuta, Har. Ancilla stamlnea, Con. The Geology of East Texas 107 Pseudoliva vetusta, Con. S. scrobiculatum, Con. Volutillthes petrosa, Con. S. alveatum, Con. V. petrosa var. indenta, Con. S. acutum var. meekanum. Lapparia pactilis var mooreana, Natica arata, Gabb. Gabb. N. limula, Con. Turlcula polita, Gabb. N. semilunata var. janthinops, Har. Latirus moorei, Gabb. Natica sp. Fusus mortoni mortonopsis, Gabb. Pyrula texana, Aldrich. Pbos texana, Gabb. Triforis sp. Distortrix septemdentata, Gabb. Mesalia claibornensis. Con. Cassidaria planotecta, Aldrich. Turritella nasuta var. houstonia, Tuba antiqua var. texana, Har. Har. Solarium bellastriatum. Con. T. duxtexta var. Har. Vaughan lists the following corals from ciJllections made on this creek and the "West Yegua^ : Corals from Elm Creek. Plabellum cuneiforme var. pachypbyllum, Gabb & Horn. Turbinolia pharetra. Lea. Madracis sp. Endopacbys maclurii. Lea. From West Yegua. Balanophyllia irrorata var. mortoni, Gabb & Horn. In 1908 Kennedy and Garrett made further examinations along Elm Creek, from the report of which the foregoing de- scription was made. The collections furnish additional species, as follows : Flabellum cuneiforme Gabb and Anomia ephippioides. Horn Area sp. Turbinolia pharetra. Lea. Clavilithes penrosei, Har? Endopachys maclurii. Lea. Syrnola trapaquara, Har. Cadulus subcoarcuatus. Solarium huppertzi, Har. East of the Brazos few fossils are found in the Yegua*, but on the Rio Grande, where the series of beds referred to this formation are more sandy, fossils are very abundant. From the collections made at exposures of these beds in the banks of this •Vaughan, T. W. Eocene and Lower Oligocene Coral Faunas. U. S. G. S. Monograph 39, p. 28. 108 University of Texas Bulletin river by Penrose and Durable^ between a point 10 miles south of Laredo and one four miles north of Zapata (Carrizo), where these beds are overlain by the Fayette, Harris determined the following f orms^ : Ostrea alabamensls. Lea. Volutilithes petrosus var. indenta, O. alabamensis var. divaricata, Har. Lea. Levifusus trabeatus, Con. var. Amomia ephipioides, Gabb. Lacinia alveata. Con. Venericardia planicosta. Lam. Cornulina armigera. Con. Cythera texacola, Heilp. Certhium sp. Tellina mooreana, Gabb. C. webbi, Har. Corbula alabamensis, Lea, Natica recurva var dumblii, Heilp. Conus sauridens, Oon. Turritella nasuta var. boustonia, Pleurotoma nodocarinata, Gabb. Har. Volutilithes petrosus. Con. MAPPED AEEA The lignitie clays and sands of the Tegua are exposed over an extensive area between the Brazos and the Sabine. The belt has an average width of 12 miles. Its greatest width, 22 miles, is found along the Neches river, while on the Sabine it narrows to 5 miles. In dip it varies from 40 feet to the mile to more than 100, and has a thickness of 400 to 800 feet. GENERAL CHARACTER The clays are laminated, thinly stratified, and massive in structure, and chocolate, dark blue, brovra, and gray in color. The eone-in-cone structure first noted on Atascosa creek in the Nueces section, is also found in the basal beds of tftis area. The sands and sandy iclays, which are sometimes micaceous, are brownish drab, buff and gray. They range from laminated to massive and are often cross-bedded. Laminated clays and sandy clays, sometimes leaf-bearing, frequently occur as lenses, pockets, and nodules in the sands, even when the latter are cross-bedded. Similarly, lenses of sand are found in the laminated, jointed clays. ^Penrose, First Annual Report Geol. Snr. Tex. p. Dumble, E. T. Geology of Soutbwestern Texas. Trans. Am. Inst. Min. Eng., 102, p. The Geology of East Texas 109 In the lower portion of the beds the clays seem to predomi- nate. The middle portion seems to carry the most lignitic matter, and the sands prevail in the upper beds. Both clays and sands weather to light colors, mostly yellow or dirty white, and some of the sandy clays show typical bad- land weathering. The topographic expression is generally flat. In the upper beds, referred to this formation by Baker and Suman, some of the sands have a poreelaneous cement, others limonitic, and still others contain streaks and balls of white clay having the appearance of porcelain. Lignitic material is abundant, disseminated through the beds in fragmentary form, as carbonaceous coatings, and in len- ticular beds; but only a few deposits of workable lignite are known to occur in the Yegua east of the line of the Interna- tional & Great Northern Railwaj^ in Houston county. Gypsum is very abundant. In the lower portion of the beds, where it predominates, it occurs as large masses of selenite of irregular form. Elsewhere it occurs as crystals of selenite, sometimes of large size, or as fragments intermingled with the sands and clays. One of the most unusual and characteristic features of the Tegua in this area is the quantity of clastic selenite which oc- curs. At times the particles of this mineral equal or exceed in amount the quartz grains in the sandstones. Saliferous strata also occur. The cannon-ball concretions of the Rio Grande are found here in abundance. While some of these are of spherical shape, as on that stream, many of the clay-ironstone concretions are in the form of flattened masses, some of them 2 to 3 feet in diameter. They are usually altered to limonite, and these limonite concretions and impregnations are characteristic of the beds east of the Trinity. Occasionally the limonitic con- cretions have streaks of calc-spar through them, but true cal- careous concretions are apparently absent. Silicified wood is plentiful as logs of large size and as fragments scattered through the formation from bottom to top, but none of it is opalized. Marine invertebrate fossils occur occasionally as poorly pre- served casts in connection with pockets or concretions of 110 University of Texas Bulletin greensand marls. Fossil plants are found abundantly at many- places. The relation of the Yegua to the underlying Marine was dis- cussed in the description of the Nacogdoches beds which con- nect the two. SABINE RIVER SECTION On the Sabine river the outcrops of the Yegua are unim- portant: According to Veateh they are characterized by un- fossiliferous lignitic clays with large calcareous concretions and are the lithological counterparts of beds of the Lignite phase of the Wilcox. His only section is that of a bluff nearly four miles south- west of Columbus, which shows: 1. Fine white sand, 2 ft. 2. Dark gray to blue sandy clay with fine sand partings and occasional beds of yellow sand, in many places a foot thick. Contains many poor plant impressions and a few calcareous concretions, 28 ft. Dip S. 20° B. 1:20. A quarter of a mile south of the above outcrop, at Lawhorn's bluff, 26 feet of laminated sandy clay, containing many large calcareous concretions, is exposed. A bed of impure lignite, a foot thick^ occurs about three feet above low water-level. Dip S. E. 1:70. Three shelves of dark colored clay appear near water level between Lawhorn's bluff and Robinson's ferry. At one of these the bed is 6 feet thick and has the usual covering of light colored sands. Deussen, in his plat of section^ shows a series of clays or shales one-fourth mile below Robertson Ferry carrying such Yegua forms as Fleurotoma terebrifomiis, Marginella semen and Gorbulat oniscus. This is the uppermost bed of Yegua known on the river, as half a mile below it Veateh found the Jackson well exposed. ^Water-Supply Paper 335, Plate W- The Geology of East Texas 111 SANTA FE RAILWAY SECTION The exposures along the Santa Fe Railway are not very sat- isfactory. The last Cook's Mountaia was seen at Birdwell siding. A mile and a half south of Brunson there is an out- crop of lignite which is also found in wells drilled in the vicinity. Between Mile Posts 106 and 101 the interbedded clays and sands appear in the cuts. The contact with the Jackson is supposed to lie between Mile Posts 101 and 100. TEXAS & NEW ORLEANS RAILWAY SECTION. On the Texas & New Orleans Railroad the base of the Yegua is found in a cut about one mile south of Piatt. Near the base of this section there is exposed 5 feet of a chocolate-brown thinly laminated shale stained yellow with sul- phur. Next in upward succession comes 3 feet of light biiff or gray, cross-bedded, medium-coarse material, which has the tex- ture of sandstone, but is made up for the most part of angular fragments of platy selenite. It is much cross-bedded. In up- ward succession it is found that the selenite clastic is inter- bedded with light gray sandy shale containing many frag- ments of silicified wood. The materials of this formation weather mainly to a light creamy buff, although locally they are yellowish brown from limonite. The soils of the formation are either of a light buff color, or are grayish and brownish mottled, or rather uniformly reddish-brown. Strike N. 60° E. Dip 2° S. E. In the cuts to the south evidence of local folding was ob- tained, one small anticline being noted. The following section was noted south of Bridge 135-F: 1. Chocolate colored, laminated shale 4 ft. 2. Gray to brown gypsiferous sandstone, 2 ft. 3. Drab and reddish-brown mottled clay, 3 ft. 4. Drab colored, soft, clayey shale. Contains a layer of hard limonitic shale, 25 ft. South of Manton a thin-bedded sandy shale seemingly cal- careous and rather resistant to weathering is exposed in a few 112 University of Texas Bulletin small lOuttings. It is of a gray to drab color. This same mate- rial was noted near Dunagan and here it is covered by about 2 feet of a dark-gray sand, which carries much silicified wood in large fragments and a thin layer of gravel made up of rounded pebbles of quartz, jasper, and clay iron ore. Between Dunagan and Pluntington cuts expose thin-bedded gray gypsif erous clayey sandstone overlain by a gray sand which contains gravel lenses and many fragments of silicified wood. There is a brown limonite layer occurring in the thin-15edded material here that is fairly persistant. ST. LOUIS SOUTHWESTERN RAILWAY SECTION The upper portion of the Yegua section in this vicinity is shown along the St. Louis Southwestern Railway between Broad- dus and Monterey. Broaddus in San AugTistine county is located about the middle of, the Yegua section and the line runs southwestward to Monte- re^, where it strikes the contact of the Yegua and Jackson. Light brown laminated sands outcrop ^ mile southwest of Broaddus. These contain brownish carbonaceous fragments and thin plates of limonite-cemented sand. Silicified wood is abun- dant. These beds have a thickness of about 4 feet. They weather light greenish-gray and brown, and contain a variable percentage of clay. The brownish layers are in association with films of limonite. At the cut 200 yards south of Mile Post 668 and between that Mile Post and Broaddus station is the following section: 1. Very light gray-brown sandy clay with thin non-con- tinuous films of limonite varying from 1-32 tloi 1-8 inch in thickness, 4 ft. 2. Light chocolate-brown carbonaceous clay, sandy, 4 in. 3. Dark chocolate-brown carbonaceous clay 6 in. 4. Light brown sand, 2 - 3 ft. The same section in general is found at Bridge 310, one-fourth mile south of Broaddus, where the very dark brown carbona- ceous shaly clay II/2 feet thick, is underlain by 2 feet of very light brown clayey sand fracturing into compact rectangular The Geology of East Texas 113 blocks, and carrying plant fragments. A silicified log was found in place in the brown layer. In the lower sand thin plates of light gray indurated sandstone are found locally. Thin non- continuous layers of limonite are common and one long cylinder- shaped concretion made up of concentric layers of limonite- eemented sandstone was found in the lower clayey sand. A good section is found in a gully to the south of the north end of this bridge. Here the laminated, clayey sands are ex- posed for a thickness of 8 feet. The laminae are plainer and finer at the base, while above, the blocks fracture semi-conehoi- dally into irregular fragments. The color is light brown, and large, concentric limonitic concretions (2 or 3 feet in long dimension) are found. Under Bridge 309 there is about 5 feet of clay, light chocolate- brown at the base and light sulphur-yellow above. The clay con- tains in places thin, non-continuous, brown carbonaceous layers and little balls and lenses of sand. It is speckled and streaked with rusty limonite which also coats fracture pilanes. At Bridge 308 are streaks of yellow sulphur in the clays. Above are about 10 feet of light-brown case-hardened sands with streaks and blotches of yellow sulphur and brownish limo- nite. Thin, irregular and non-continuous contorted beds of more compact sand are scattered thz'ough the section. This passes into a partially "shelly" gypsiferous sandstone at the top. In the superficial layers overlying the clay in the next cut to the southward (Mile Post 666) are rough boulders of a ferru- ginous-cemented hard conglomerate made up of pebbles of quartz, chert, and silicified wood. This is the local representa- tive of a Lafayette ferruginous conglomerate which is wide- spread in southwestern San Augustine county, extending at least from north of the Marine outcrop as far south as the Cata- houla outcrop. The basal bed in this cut is shaly dark-drab sulphurous clay, 5-7 feet thick, and weathering a light yellow. The sulphur is in streaks, blotches, or small roundish concretions which are rough, sometimes mammillary, on the surface. The dip is 3° S. 15° W. (Mag.). The section is: 114 University of Texas Bulletin 1. Surficial Lafayette; light buflf to dark-brown, mottled, mainly sand, but with gravel and rough rounded bowlders ot ferruginous-cemented sand-matrixed con- glomerate, some of which are 6-8 inches in diameter, . . 4 ft. 2. Light brown, medium-grained sand, speckled brown and whitish, laminated. Whitish grains, perhaps decom- posed gypsum, 3 ft. 3. Fine light, gray-brown, clayey sand, impregnated with salt, making semi-badlands, imperfectly laminated through- out, but with better laminae at top. Top layers sulphurous 8 ft. 4. Light drab clay, weathering dark, dirty-green, with con- cretions and thin, non-continuous lenses of clay iron- stone S ft. 5. Brown medium-grained, gypsiferous sand with sulphur con- cretions, plant fragments, and limonite. Weathering into pinnacled semi-badlands, 10 ft. 6. Gray-drab clay, weathering dark dirty green, with whitish concretions, . 2 - 4 ft. 7. Layer with white rounded concretions, perhaps calcareous 2 in. 8. Black to dark brown clay ironstone, amorphous, compact, with dendritic markings, probably of manganese dioxide. Iron in form of limonite 1 ft. 1% in. 9. Clay like (6), but without concretions, 2 ft. 10. Clay ironstone like ( 8 ) 1 ft. 2 % in. 11. Clay like (9) 3% ft. 12. Thin-bedded, shaly limonite-stained clay...... 2 in. 13. Brown limonite-stained clayey sand; at top consisting of thin bands of dark-green clay, alternating with sand. Contains thin bands of dark-brown ferruginous sand- stone 2 ft 14. Shaly, dark-drab, sulphurous clay, weathering light yellow, 7 ft. The two top members of the Yegna section are approximately horizontal. The dip varies from 3° to 0° within 300 yards, go- ing southward. In the small cut just to the south of the one last described, there is 6 feet of Tegua which either belongs on top of No. 2 of the last section, or else grades into Nos. 2 and 3 horizontally. The lower 3 feet is rather massive, laminated sand, alternating layers of light-buff to brown, succeeded above by 6-inches of very dark-brown carbonaceous shale, overlain by 3-inches of whitish to brownish-yellow laminated clay, with 3 feet of dart- TJie Geology of East Texas 115 brown clay on top. There is a small anticline in the central portion of the outcrop of the carbonaceous layers and the entire length of the cut forms a low anticline which includes the email one. At the south end of the cut No. 2 of this section comes down below the track level for its entire thickness of 3 feet. It is here more indurated than in the last section, but the induration is irregular and produces a rather "shelly" appear- ance. The southern limb of the anticline probably brings these strata below Bridge 307, where there is 6 to 8 feet of brown and gray, laminated, soft sands under a 6-inch carbonaceous brown shale, overlain by 2 feet of brown, shaly clays, capped with 6 feet of light drab, laminated sand. Sulphur is found just above the carbonaceous layer. The cut at M^ile Post 665 shows 4 feet of light brown, sandy clay with limonitie concretions, weathering light buff. There is some sulphur, especially in juxtaposition with the concretions. At the cut 200 yards south of Bridge 304 and 400 yards south of Mile Post 665 there is at the base 3 feet of light brown sulphur and limonite-blotched sand passing upwards into 3 feet of car- bonaceous, brown clay, weathering dark reddish-brown. In the cut 200 yards south of Mile Post 664, at the north end, is 4 feet of the dirty green clay with white nodules. The un- weathered portion is lighter green, or light grayish-brown. As the dip is northward, this clay ovei'lies the beds farther south, which are light green, clayey sand, at least 10 feet thick. Small balls and lenses of light-gray sandstone are found. These clayey sands weather very gray and are approximately horizontal at the south end of the cut. In the cut at Mile Post 663 the dip is 11/2° S. 45° W., but somewhat variable. The section here is : 1. Light gray clay, weathering dirty green, with large, dark brown, lenticular ironstone concretions coated on fracture planes with black oxide of manganese, 5 ft. 2. Light, greenish and grayish, sandy clay with irregularly distributed brown plant fragments 10 in. 3. Dark brown carbonaceous clay 2 in. 4. Light green sticky clay, 4 in. 6. Light gray, medium-grained sand, with clastic gypsum 116 University of Texas Bulletin flakes. The lamination is imperfect, but is apparent from local, thin, indurated layers of sand. Weathers into semi-badlands, 6 ft. Some of the concretions in the upper member are 20 feet in diameter. Two hundred yards southeast of Mile Post 663, with its top 6 feet below the track level, is 6 feet of loose sand varying in color from light buff to light yellowish-brown, depending on amount of iron present. The sand weathers into semi-ibadlands with rain-erosion monuments from 1 to 2 inches in heaight. At this locality is a small prairie 4 or 5 acres in extent and having a small "saline" on its western border. The Lafayette has a thickness of 7 feet at Warsaw. The long trestle over the Attoyac and Angelina just above their junction is over % mile in length. No terraces are to be seen in this flood plain, although there are several flood-channels cut into the general bottom level. Both banks of the flood-plain are com- posed of red and gray Lafayette sands and both rise gradually to 25 or 30 feet above the general level of the flood-plain. A very flat country begins to the west of the Angelina river and continues westward across Angelina and Trinity counties, under- lain in part by the Yegua and in part by the Jackson clays. Light gray sands, succeeded above by 8 feet of brown, car- bonaceous sandy clay, varying in color, on account of the amount of carbon present, from light chocolate to nearly black, is found in the flrst cut west of Mile Post 659. The light sandy layers break with a semi-eonchoidal fracture and contain plant fragments. Unconformably overlying the brown clay, is 4 feet of light gray, friable, cross-bedded sandstone, hardening along joints. This sandstone is composed of coarse, subangular grains of quartz, grains of the same size and contour of a light colored mineral and some black chert. It contains streaks and balls of a white clay-like substance which gives the appearance of porce- lain. It contains pebbles or emulsion balls of white clay and its contact with the underlying clays forms a line of small springs. It is probably the base of the Jackson at this point. The maxi- mum thickness is 6 to 7 feet, 4 feet being an average. Its basal 2 inches, in the middle of the cut, is partially quartzitic. The Geology of East Texas 117 Although, in the east of the cut, its contact with the underlying Tegua runs as a plane surface for 300 yards, to the west, it occupies an erosion channel in the Yegua clays and is much more cross-bedded. Cross-bedding and contorted bedding is very common in the middle of the cut. Three hundred yards east of Monterey and 200 yards east of the west end of the cut, is a lens of light-brown clay coming in between two cross-bedded layers and dipping eastward. The general color of the cross-bedded material is very light gray. At one place it is overlain by shaly porcelaneous sandstone re- sembling the Jackson. HOUSTON, EAST & WEST TEXAS ET. SECTION. The Houston, East & "West Texas Railway is somewhat barren of good exposures but from the divide near Lufkin there are creeks running northward into the Angelina and southward into the Neches which parallel the line of road and these give better views of the formation. East of Lufkin, where the Angelina and Neches river railroad crosses Durasno creek, we find an exposure which has at the base a layer mainly composed of clay ironstone concretions from 2 to 5 feet in diameter and from 4-inches to a foot in thickness. The material of these gray concretions is very fine-grained and is well compacted into an amorphous mass of hard rock. In color it is a light greenish-gray in the interior, but the outside is covered with a 1,4 inch film of brown or reddish limonite stain. Some of the concretions have good cone-in-cone structure. This concretionary layer- is overlain by 6 feet of thinly laminated light gray sandy clay shale. This is near the base of the Yegua and lithologically is similar to the basal beds on Elm creek. The next exposure in upward succession shows 4 feet of choco- late-brown, carbonaceous shale, with medium-grained, limonite- stained sand at the base. Higher up, an exposure gives 6 feet of light gray sand, fine-grained and thinly laminated, with filmy partings of brown carbonaceous matter. The highest exposure on the creek exhibits 3 feet of dark chocolate-brown, thinly- laminated clay shale. 118 University of Texas Bulletin From the head of Durasno creek we cross the divide between the Angelina and the Neches and seven miles south of Lufkin find the headwaters of Bear creek, a tributary of the Neches river, which flows in a general southerly direction and gives other sections of the upper Yegua. The highest exposure on this creek shows 2% feet of brown friable sandstone containing flakes of selenite. The bedding is not very conspicuous and the beds are of medium thickness. The rock is irregularly stained with limonite and contains small cl ay balls. The next section below has, at the base, one foot of blue, fine- grained sand, streaked with yellowish-brown limonite stain, overlain by 3 feet of thinly-bedded, brown clayey sand carrying brown plant fragments. The limonite seams have sometimes the form of slender cylinders. Where these cross each other on the surface they weather out into figures resembling the fillings of the cracks in sun-cracked muds. The limonite-stained layers are locally hard enough, because of their iron-stained content, to be called sandstone. This 4-f t member outcrops in its full thick- ness for a considerable distance along the stream. It is a friable, thin, and irregular-bedded sandstone, predominantly brown in color, but mottled with little contrasting shades of brown. The color is due to carbonaceous material or limonite, or to local leaching. In texture it is fine to medium-grained angular sand. Flakes of selenite are found sparingly. Locally, a thin non- continuous lens of brown carbonaceous clay or sand is noted. Much of it is stained and seamed with yellowish irregular blotches, probably of sulphur or alum. All of it carries plant fragments of a dark chocolate-brown color: Farther down comes in 3 feet of thinly laminated chocolate brown clay with numerous leaf impressions. The clay is very soft and friable. It is underlain by 1 ft. 3 inches of thinly laminated, gray, carbonaceous, fine-grained sand, which has small non-continuous layers of brown carbonaceous matter and abundant plant fragments, sometimes carbonized, but generally dark-brown. The next exposure exhibits the following section : The Geology of East Texas ' 119 1. Light drab to chocolate clayey sand, carbonaceous and gypsiferous, 4 ft. 2. Very carbonaceous, fine, soft clay with streaks of sandy clay, and many leaf impressions 1 ft. 3. Chocolate-brown to greenish-gray, gypsifer.ous and car- bonaceous clayey sand and sandy clay, 1 ft. 6 in. Farther down is 7 feet of fine-grained sand, brownish-cream to light chocolate-brown in color, containing sparsely distributed selenite flakes. The lowest 3 feet is more massive than the upper portion, which is more leached than the lower beds and weathers a lighter cream color. This member outcrops for about a mile along the creek. In places 10 feet of it is exposed in nearly per- pendicular banks, weathering creamy-buff. Underneath the surface the sand is a light blue-gray. Next is 4 feet of thin-bedded, laminated, carbonaceous, brown and drab clayey sand with plant fragments, weathering light gray. The lowest beds downstream are soft, fine, light-gray sand, gypsiferous and carbonaceous, exhibiting more or less lamina- tion. These sections bring out plainly the sandy character of the upper beds of the Yegua. A short distance south the fossilif- erous clays of the Jackson appear. TEXAS SOUTHEASTERN AND GROVETON, LUFKIN & NORTHERN RAIL- ROAD SECTION The sections exposed along the Texas Southeastern and Groveton, Lufkin & Northern railroads between Lufkin and Apple Springs give a fair idea of this portion of the Tegua. In the first cut west of the junction of this road with the St. Louis Southwestern Eailroad at least one-half mile east of Mile Post 15 and near Lufkin, are the following beds : At the east end of the cut is 2 feet of chocolate clay weath- ering on the surface to light-gray. This disappears 100 feet farther west, where the overlying surficial sands come down to meet it in a line diagonal to the bedding. At the very base of this lower member is a light sulphur-yellow, compact clay very similar to that noted in exposures in the lower reaches of 120 University of Texas Bulletin Procella creek. "Westward in the same cut the section is made up entirely of Lafayette material, and, at the extreme west end, a maximum of 3 feet of T)lue-gray sandy clay is unconform- ably overlain by this Lafaj'ette. One-fourth mile west of Mile Post 1&, and 8 feet below the track-level, there is at the base 2 feet of light-gray, medium- grained sand, weathering buff. Immediately to the west is 2 feet of brown to drab clay, apparently "underlying the sand. Here are large fragments of silicified wood. Some of the. clay is compact, brittle, light-gray, and probably calcareous. There is 4 feet of this clay in the southwestern portion of the cut. ■ At cut one-fourth mile east of Mile Post 14 there is 4 feet of thin-bedded, compact sandstone, very light-gray in color. Most of it is a medium-coarse grit with a large proportion of eroded crystals of selenite. In some of the sand there are small clay balls less than one-third inch in diameter. The cut at Mile Post 14 shows 4 feet of cross-bedded and laminated sand with clastic selenite and sandy clay overlain by 7 feet of amorphous, mottled dark-blue-gray and red clayey sand of the Lafayette. There is much petrified wood here. At the second cut one-half mile southwest of Mile Post 14 there is at the base ten feet of typical light-gray, contorted and cross-bedded sands, overlain unconformably by 5 feet of mottled sandy clay of the Lafayette. The lowest beds, as usual, contain petrified wood. The sand, in places, is thin- bedded, in other places, massive. In induration, it varies from quite compact to very friable. Some of it has elastic selenite and quite a large proportion of clay. The long cut at Mile Post 12 exposes 10 feet of thin-bedded or shaly sand with thin-bedded lenses of clay ironstone, the largest of which are 5 to 6 feet in diameter. At the west end of the cut, near the base, two small layers of thin-bedded fer- ruginous sandstone are separated by 1 foot of cross-bedded laminated sand. Directly west of Mile Post 12 the following section is ex- posed, beginning 10 feet below the track level: 1. Gray surface sandy soil with humus, 4 ft. 2. Light sulphur-yellow laminated sandy clay 4 in. The Geology of East Texas 121 3. Thinly laminated, cross-tedded, medium.grained, light brownisli-gray, lenticular sands, 6 ft. 1 in. 4. Blue sandy clay , 6 in 5. Sand like (3), 6 in. 6. Shaly clay, 3 in. 7. Sand like (3), but containing ttiin seams of brown carbo- nous matter 2 ft. 8. Thinly laminated sandy, blue-gray clay 3 in. 9. Sand like (3), (5) and (7) 1 ft. All members weather buff. All the sands are cross-bedded and, locally, vary in thickness. The strata are apparently horizontal. In one place thin seams and lenses of brown limonite sandstone were noted. There is much petrified wood. In cut just west of Pery flag station and section house 2 feet of light-gray clayey sand with just a faint tinge of green is overlain by 2 feet of sticky, gray-blue clay with roundish clay ironstone concretions. Overlying is 18 inches of Lafa- yette mottled clay. One hundred feet west of Bridge 2.87 and 20 feet below the rail,, there is at the base 10 feet of laminated, light-blue clay with small spherical ironstone concretions up to a foot in dia- meter. These beds weather as typical liadlands, forming light buff colored, sharp gully and rounded knob exposures. Over- lying them .ire 10 feet of very thinly laminated light brown shales, limonite-stained and carrying seams of brown carbo- naceous matter, and becoming sandier toward the top. Then come, in upward succession, 2 feet of very dark-brown choco- late, carbonaceous, thinly laminated shales, followed above by 6-inches of compact, sulphur-yellow clay with carbonaceous matter, overlain by surficial rounded pebbles of granite, quartz, chert, and metamorphic rocks. Two hundred and fifty yards farther west the dip is 40° S. to 60° "W. and there is exposed about 20 feet of thin-bedded, carbonaceous sandy clay, weath- ering buff. In the long cut one mile east of Blix is exposed about i5 feet of thin-bedded, sandy shale carrying very thin seams of sulphur-yellow color and of limonite. On surface exposures the color is light buff. There is considerable cross-bedding and much silieified wood. 9-ET. 122 University of Texas Bulletin Just south of Vair the cut at Mile Post 21 exposes 5 feet of dark drab to chocolate-brown carbonaceous shale. At a cut 20-1-2 miles from Groveton there is at the base 3 feet of light-gr.ay, laminated clay with layers about 1-16 inch thick of linionite-stained hard clay. Above is a 6-inch layer of brown carbonaceous clay, overlain by 4 feet of clay similar to that at the liase. Fragments of silicified wood are found in thfi clay. Then, to the westward, begins a series of light gray sandy clays which weather into badland forms very light buff in color. In these clays are nodules and disc-like concretions of clay ironstone and fragments of silicified wood. Eighteen and three-quarter miles from Groveton, a cut ex- poses 3 feet of light brown, laminated clay, overlain by 2 1-2 feet of soft, medium-grained, gray sandstone. The clay is gypsiferous. The dip is 3° to the northeast. About 150 yards northeast the rock is mainly gray sand in- terbedded with very thin clay seams. The sand, which is mottled in many places, is more massive and predominant at the top. There is 6 feet of this probable Lafayette surfieial member. For 1% miles northeast of Apple Springs cream-colored clays containing fragments of silicified wood and weathering into semi-badlands form the surface exposures, but, not over 4 feet are found in any one section. There is in these beds a considerable amount of iron occurring as disc-shaped concre- tions and in thin layers. These are the top of the Tegua beds in this traverse. This section, beginning not far from the base of the last, runs southwest instead of south. Apparently the middle por- tion of the section is more sandy than was found east of the Attoyac, and the upper portion carries large quantities of silic- ified wood and flattened cannon ball concretions which were not observed there. INTERNATIONAL & GREAT NORTHERN RY. SECTION The Cook's Mountain-Tegua contact crosses the Interna- tional & Great Northern Railway about half way between Mile The Geology of East Texas 123 Posts 41 .and 42, or 3^^ miles south of Crockett. Here the light colored gypsif erous clay of the Tegua is seen for thei first time in this section. One-fourth mile north of Mile Post 42 is 4 feet of Yegua dark-gray sticky clay, weathering cream-colored and crack- ing on surface. Here are petrified logs, the largest of which is 1% feet in diameter. The cut one-fifth mile north of Mile Post 44 (just north of Cut siding) exposes 10 feet of Tegua coarse sand. The quartz grains are subangular and the sand contains grains of clastic selenite. There are also fragments of silicified wood. The whole exposure is lightly mottled. The original color of the sand is buff or cream. Now it is colored in blotches and patches with light brick-red. There are a few angular frag- ments of black material, perhaps chert. Some of the wood contains veinl'ets and botryoidal incrustations of hyalite. Prom these localities Prof. Berry had determined the follow- ing species of wood: I. & G. N. Ry. Cut. Between Crockett and Lovelady: Lower Yegua Other Gulf States. Phoenicites occidentalis Berry Dryophyllum n. sp. Claiborne Myristlca catahoulensis Berry Cedrela n. sp. Jackson Mespilodaphne n. sp. Jackson Nectandra n. sp. Jackson Nectandra n. var. Nyssa n. sp. Claiborne Carpolithus n. sp. Prom here to Wooters Station (one-fourth mile west of the coal mine and just south of Mile Post 48) the topography is typically flat Yegua. Some small exposures of Yegua clay weathering light yellow are seen. The cut at Mile Post 48 and south of there to Wooters Station shows 20 feet of Yegua drab sandy, partially laminated clay, weathering cream-colored and containing thin flakes and concretions of limonitic-cemented material. Petrified wood is found here in abundance. A specimen collected at "Wooters was sent Prof. Berry who identified it as Cupressinoxylon dawsoni Penh. 124 University of Texas Bulletin Tegua light drab clay with limonitie plates and concretions is found underlying the extensive flat at Lovelady and also between Mile Posts 53 and 54. Fragments of silicified wood are found in .all these exposures. The flat surfaces are cov- ered with a plentiful sprinkling of Lafayette-derived gravel . similar to that about Huntington and elsewhere in Angelina county. These gravels probably once occupied a higher eleva- tion than they do at present, but their position has been suc- cessively lowered by the erosion of the more easily transported materials under them, leaving them as a more or less permanent surface capping in a region of low relief and consequently of streams with low powers of transportation. Between Mile Posts 53 and 54 a large portion of the material exposed is medium-grained, gypseous sand stained yellow locally, perhaps with sulphur. Just north of Mile Post 54 the drab clay contains thin plates of very light gray opaline-ce- mented sandstone. Between Mile Post 54 and 55 coarse Bands, sometimes partially consolidated, contain flakes of clas- tic selenite. Overlying this the Jackson is first encountered to the south of Mile Post 55 as thin, irregular and shelly-bedded, friable, creamy and buff sandstone. Nevil's Prairie, which lies southwest of Lovelady, is under- lain by the beds of the upper Yegua which, in this vicinity, carry great quantities of silicified wood and numerous limoni- tie concretions. At the southeast margin of the prairie on Cedar creek is five feet of chocolate imperfectly laminated jointed clay with a few small lenses of sand, overlain by lami- nated grayish sand. Three-fourths mile downstream from the last mentioned exposure on Cedar creek is the following sec- tion: 1. Brown carbonaceous shaly clay, locally li^itlc 2 ft. 2. Greenish-drab sticky ball joint clay with leaves 1 ft. 3. Poor quality brown lignite 1ft. 4. Brown carbonaceous clay From these localities Berry identified the following forms : The Geology of East Texas 125 Near Antioch, 4 miles southwest of Lovelady. Upper Yegua. Other Gulf States. Anemia eocenica Berry Wilcox Mimosites georgianus Berry Claiborne Jackson Cupanites n. sp. Claiborne Sapindus georgiana Berry Claiborne Jackson Sapindus formosa Berry Wilcox Claiborne Laurlnoxylon n. sp. Claiborne N evil's Prairie, 5 to 1 miles sowfhwest of Lovelady. Upper Yegua. Arundo pseudogoepperti Berry Lygodium kaulfussi Heer Momisia americana Berry Ficus n. sp. Inga n. sp. Mimosites georgianus Berry Sophora wilcoxiana Berry Wilcox Citrophyllum n. sp. Sapindus georgiana Berry Sapindus formosa Berry Wilcox Sterculia n. sp. Persea n. sp Oreodaphne n. sp. Mespilodaphne n. sp. Nectandra n. sp. Apocynophyllum n. sp. Other Gulf States. Claiborne Jackson Claiborne Jackson Claiborne Jackson Claiborne Claiborne Claiborne Jackson Claiborne Claiborne Jackson Claiborne Claiborne Claiborne Claiborne Claiborne Jackson Claiborne Jackson Claiborne Jackson TRINITY RIVEK SECTION On the Trinity river the exposures referred to the Yegua extend from Robbins Ferry, northwest of the mouth of Kel- lison creek, to Calhoun's Ferry, just south of the line between Houston and Walker countie.s. The width of the beds at this point is about eleven miles and along the river there are bluffs that give excellent exposures of the formation. It will be seen from these sections that with the exception of the very top, the beds are much more argillaceous than in the Neehes basin and that they carry beds of lignite of work- able thickness and quality. This condition continues to the westward. Kennedy placed the contact at Alabama bluff, several miles up the river, where the first selenitic clays are seen, but Baker and Suman decided that this was part of the Nacogdoches or 126 • University of Texas Bulletin transition beds between the Cook's Mountain and the Yegua and placed the line at the base of the more massive clays which are unfossiliferous. No exposures were found below the final appearance of the Nacogdoches just above Robbins Ferry and the mouth of Kel- lison creek, where the following section occurs: 1. Blue gray, clayey sand with a few small calcium carbonate cemented sandstone concretions; structureless, change in color to lighter shades as top is approached. Top 5-10 feet is a reddish brown color 20 25 ft. 2. Dark blue-gray, very sandy, muscovitic joint clay, with small lignitic lenses and black carbonaceous plant fragments and clay ironstone concretions. Imperfectly laminated, 15 ft. 3. Cross-bedded sand, carrying lumps of clay and with erosion unconformity between it and underlying clay which is believed to be local. Sands, medium^-grained, light greenish-gray in color, containing a number of lignitized wood fragments and at top a thin layer of limonitic sandstone, 3 ft. 4. Clay like (2). Upper 2 feet sandier than lower portion, 8-10 ft. Spring creek, or Spring branch, enters the Trinity river be- tween Kellison creek and Westmoreland Bluff. It has steep, deep, and narrow, gully-like banks cut in the present river flood plain. The main creek and its branches have sent arms with cuspidate margins up into the second bottom terrace. The lowest exposure forms a falls. The section here is: 1. Grayish-brown, sandy, terrace alluvium, with the calcareous nodules characteristic of the terrace alluvium in this vicinity. 2. Br(Oiwnish-black to brown, carbonaceous, shaly clay. At least 1.5 ft. 3. Lignite, good quality, hard, firm, of dull lustre. (In all probability the same bed as that exposed in Westmoreland Bluff) 4.5 ft. 4. Gray drab sticky clay 1.5 ft. "Westmoreland Bluff is four miles west of the tovm of Weldon. The section is as follows : 1. Mottled; grayish and rusty, river alluvium with the usual ferruginous cemented gravel layer at the base. Very The Geology of East Texas 127 sandy and gravelly. Has calcareous concretions and _ represents the second bottom of tlie Trinity River 2. Carbonaceous, black, finely laminated shale, locally lignite, with petrified logs, one of which measured three feet in diameter, 3 ft. S. Blackish carbonaceous shale with small selenite crystals, thinly laminated. Much of it dark.brown in color. Greenish-drab, sticky, laminated clay. This member is represented at the east or upper end of the bluff by 25 feet of sandy clays, interbedded with dark, car- bonaceous shales. The clays are mainly light drab in color. At one place were found in situ the lignitized roots of a tree. Between the east and west ends of the bluff this horizon is occupied by a very much cross- bedded, laminated, iron-stained and concretionary, brown sand containing large trunks of trees and lenses of clay. The large petrified logs are black in color and silicifled, in places changed to finely fibrous brown calcite. The outer surfaces of the logs are rough and ribbed as if they had undergone partial decay .before being buried. The concretions are mostly flat disks or imperfect, sometimes tuberous, and "cannon balls". They are composed of fibrous calcite and iron carbonate 7 25 ft,. 4. Grayish-brown, interbedded sands and clays. One foot of bluish-black carbonaceous sandy clay in middle of lower sand member. Upper three feet yellowish-brown clay, 16 ft. 5. Black and brown, carbonaceous clayey sand with small black leaf fragments 9 in. 6. Laminated, dark-brown sand 1 ft, 7. Greenish-drab, compact, sticky clay, 6 In. 8. Chooolate-brown, thinly laminated, carbonaceous shale.... 1ft. 9. Lignite. Middle of bed compact, hard, of dull lustre, and good quality. Top and bottom badly checked and slaked by weathering. Covered with water at overflow stages 3 1-2 - 5 ft. 10. Dark drab, fine clay, fracturing into small fragments. Unctuous and polished on fracture surfaces, 2 ft. 11. Sand, more compact, laminated, brown in color, with small crystals of selenite. Lower one foot with greenish- blue cast. Stained rusty with limonite along lamination planes and, locally, yellowish with sulphur 5 ft. 12. Unconsolidated, fine-grained, dark gray, micaceous sand. .4.5 ft The two upper shoals at the bluff are made by the lignite bed, which lies at low water level. At the southern or lower end of the bluff the coal bed forms a low broad anticline with its 128 University of Texas Bulletin shorter axis in an east-west direction, in which direction it out- crops above low water level for about four or five hundred yards. On both limbs where it dips below the low water level it forms a shoal. Lying above (2) farther upstream is plastic slaty gray clay, above which is loose, coarse to medium-grained gray and brown loose porous sand in which are limonitic concretions. There are balls and lenses of blue clay in the lower portion of the sand with their longer axes arranged as various angles with the horizontal, indicating local unconformity and erosion of underlying clay before the deposition of the sand, similar to conditions at the lower plane of the cross-bedded sand layer in Westmoreland Bluff. The following section is shown at Hyde or Spanish Bluff on the Trinity river. The elevation of the second bottom terrace surface is here 30 feet above the first bottom surface. At the lower end of the bluff there is at the base 4 feet of greenish, micaceous, fine clayey sand, carrying lignitized logs, above this, seams of lignite interbedded with grayish sand, and at the top 1 foot of drab joint clay. The section at the main bluff is : 1. Reddish-brown, loose, loamy sand of the second bottom with fossil Vnios. Unconformity: 2. Dirty green, fine, micaceous sand, very imperfectly lami- nated, locally brown with carbonaceous matter, more laminated and jointed in the lower 6 feet, where it is brown, carbonaceous and more clayey 15 ft. 3. Impure lignite, 1.5 ft. 4. Lignite, very irregular In thickness 2 ft. A section at the lower end of Pine Bluff, Trinity river, one mile below the mouth of Negro creek, follows : 1. Alluvium with calcareous nodules, light gray at base, but brown above 15 20 ft. 2. Ferruginous-cemented Lafayette-derived conglomerate with casts of Unias 3 ft. Unconformity, involving and bevelling beds (8) to (3). 3. Greenish-gray sandy joint clay, 3 ft. The Geology of East Texas 129 4. Lignite, very irregular in thickness, 2. ft. 5. Lignite, very irregular in thickness 2 ft. 6. Gray, laminated, cross-bedded, fine sands with thin, inter- bedded layers of dark gray clay 3 ft. 7. Dark gray sandy Joint clay with fragments of lignitized logs 1 - 2 ft. 8. Compact, laminated, dark gray-brown, fine sand, lenticular, % - 1 ft. 9. Clay like (7) 1 1-3 ft. 10. Sand like (8) 1 1-3 ft. 11. Lignite, lenticular, soon pinching out 1 ft. 12. Lignitiferous shaly clay, brownish and black 1 ft. 1.3. Laminated, fine-grained, gray to brown sand, very car- bonaceous, with knife edge, thin, alternating, dark gray and black layers, 4 ft. _ The beds dip 2 degrees N. E. at the north end of the bluff. There is another bluff about three-quarters of a mile down- stream from Pine Bluff on the Madison county side. Here there is about 25 feet of Yegua, cross and wavy-bedded, laminated gray sand, with interbedded layers and pockets of drab joint clay. It is overlain by light brown, sandy alluviiim, with a surficial black sand layer. Three-fourths of a mile farther downstream, also on the Madison county side, is .a second bluff, having exposed at its base 10 feet of Yegua, gray, laminated, clayey sand, dipping about 30 to the east. Above is 20 feet of yellow, sandy, .alluvial clay: One mile farther downstream, on the Madison county side, is a third bluff with 10-15 feet of laminated, light-gray, Yegua, sandy clay in a series of very low folds. BRAZOS RIVER SECTION The base of the Yegua on the Brazos river is found in the bluff about 500 yards south of the mouth of the Little Brazos ■ river, where, overlying the fossiliferous Marine beds, there is 5 feet of unfossiliferous, pale blue clays. At Munson's Shoals the section shows : 1. Brown river loam of sand and fine gravel, 18 ft. 2. Black sandy loam and clay loam mixed with brown sand containing gravel and a few drift pebbles 2 ft. 3. Pale blue clay 8 ft. 4. Bluish-green lignitic clay, breaking into blocks and con- 130 Vmiversity of Texas Bulletin taining broken plant remains, extending- across the river and forming shoals 6 ft. At Jones ' bridge we have : 1. Yellowish gray sand, 32 ft. 2. Bluish-green, sandy clay, containing fragments of lignite and breaking into ovoid blocks, 46 ft. Penrose's section at Sulphur Bluff is as follows: 1. Light brown, hardened, sandy clay, 10 ft. 2. Lignite, 1 ft. 3. Gray sand 1 ft. 4. Lignite, % ft. •5. Interbedded gray sand and chocolate and greenish clay, turned white in places on the surface, 20 ft. The whole bluff is coated with sulphur. The contact between the overlying sands and these clays is seen on the south side of the James Hope Survey in a section showing : 1. Gray sand and gravel 1 ft. 2. Gray sand containing great quantities of silicified wood. The wood is usually in large pieces — four to six feet in length, and bleached white 5 ft. 3. Gray, indurated sand, with ledges of soft sandstone 10 ft. 4. Gray sandstone, joined and thinly bedded, forming base of Wellborn sand, 8 ft. 5. Dark brown lignitic clay, showing yellow bands from % to 1-2 inch in thickness and coated with an efflorescence of sulphur, to water, 20 ft. No. 5 corresponds to the upper brown clay of Penrose's sec- tion of Sulphur bluff. For the purpose of comparison and as showing the Marine fossils of this formation, the section as observed in the Rio Grande may be given : RIO GRANDE SECTION Ten miles south of Laredo, and about the same distance by river, above the Webb-Zapata county line, we find the first de- posits which, from their fossil-contents, we can, with certainty The Geology of East Tex'as 13] refer to the Tegua clays. This is a bluff, nearly a mile in length, on the Texas side of the river. Here are exposed a series of interbedded greensands, brown sand and chocolate clay, with lenticular masses of red sandstone. Near the top of the hill there is a bed of altered greensand containing quan- tities of fossils, among which Mr. Harris determined: Lacinia alveata, Con. Natica recur.va var. dumblei, Heilp. ■Cerithium sp., C. webbi, Har. Anomia ephippioides Gabb. Ostrea alabamiensis Lea. Cornellna armigera Con. The round concretionary masses, called cannon-balls, are abundant, both in the bed of greensand and in the red sand- stone. The chocolate, sandy clays are cross-bedded. A mile below this, a bluff on the Mexican side shows more clearly the characteristically clayey nature of the Tegua. This bluff is nearly 2 miles in length, and is composed of indurated blue or gray clay, interbedded with altered greensand and gray-hrown sands. It contains a thin bed and seams of lignite. Beyond this, a bluff', 75 feet high, shows the chocolate sands and clays, highly variegated in color — purple, red, pink, yellow and brown — and capped by a brown sandstone . which weathers black in places. A considerable amount of iron pyrites and gypsum are present. About the line of Webb and Zapata counties there is a bluff 60 to 100 feet high, which is a half mile or more in length. The beds are nearly horizontal, as seen from the river, which here flows east. The base of the hill shows a band of buff and green- ish sands, slightly calcareous, with large concretions — 8 to 10 feet in diameter. This is overlain by an extremely hard, limy band of grayish color, which shows on its upper surface a breccia of a very large gasteropod. Overlying this is a series of sand of varied colors and a second limestone layer, very rich in fossils, including such forms as Conus sa/uridens, Con.; Ostrea, alabamiensis, Lea; 0. Geol. S. "W. Texas, Trans-Am. Inst. Min. Bng., pp. 961-964. 132 University of Texas Bulletin divaricata, Lea ; Volutilithes petrosus, Con. ; V. petrosus vax. indenta, Con.; Tellina mooreana, Gabb; CorbuLa alabamiensis, Lea; Cytherea texacola, Heilp. ; Natica recurva var. dumllei, Heil. -jTwritella nasuta var. Tioustoma, Har. ; Yenericwrdia plam- costa, Lam. The next bluff, 2 miles below, on Texas side, showed only- brown sands, without fossils, for a height of 60 feet, but at the mouth of Dolores creek we again find the greensands in hill 20 to 35 feet high, with beds of oysters from bottom to top. • Four miles below this there is a low reef of hard, gray lime- stone, weathering to a greenish-gray color. It is concretionary in places. Four miles above San Ignacio there is a bluff 300 y.ards long and some 60 feet high. Below the alluvial deposits it is composed of buff sands and sandstones, with seams of lignitic clays, sands and greensands. At the top of the sandstone there is a fossil-stratum about 8 inches thick. This gave: Pleurotoma nodocarinata, Gabb (?), Levifusus trabeatus, Con., var. Tellina mooreana, Gabb. Corbula alabamiensis, Lea. Venericardia planicosta, Lam. Cytherea sp. Natica recurva var. dumblei, Heilp. (Volutilitbes petrosus. Con. Ostrea alabamiensis. Lea. ' Gypsum and cannon-balls occur, as well as numerous white calcareous concretions. The bombshells contain traces of lig- nitic materials. The dip here is normal — S. B. Two miles below, a bluff on the Mexican side of the river, composed of the gray sandstones with calcareous concretions, shows .a distinct north- east dip. The same sandstone, still dipping northeast, appears as a reef at San Ignacio. The exposures at the mouth of Sali- dita creek, about 2 miles below San Ignacio, show a bed of siliceous limestone, with beds of altered greensands. This is overlain by a buff sandstone which, in its next appearance, is seen to be cross-bedded and jointed. Four miles below San Ignacio the river bluff shows this same buff sandstone underlain by greensands. The buff sandstone The Geology of East Texas 133 is quite calcareous, carries gray nodules .and shows concentric weathering. A mile below this exposure the dip changes from northeast to northwest, and shows somewhat greater angles than is usual in these beds, amounting to .as much as 10°. The materials ex- posed are semi-indurated sands, with more compact boulders of the same material. This is overlain by blue and green fer- ruginous clays, which weather a deep-red and show concentric weathering. White, calcareous concretions abound in this bed. Yellow, sandy clay, becoming more compact toward the top, succeeds the heavy clays. No gypsum was seen, and but little sulphur. Two miles below, the dip again changes to southeast, and the buff sandstone shows beds of flagstone, which are somewhat calcareous and contain black, chert grains. These beds con- tinue to a point 4 miles north of Carrizo, where we find the contact of the clays of the Yegua with the Fayette sands. CHAPTER VI. CLAIBORNE CONTHNTUED Fayette NAME The name was originally used by Penrose^ for the entire series of deposits lying between the top of the Marine beds and the Orange Sand or Lafayette. As has been already shown, the basal member of these beds was separated under the name Yegua. Further investigation proved that the name still em- braced deposits of different ages, and it was finally restricted to the sands and light colored clays overlying the Yegua and, if the Frio belong in the Upper Eocene, the uppermost bed of the Middle Eocene of the Texas section. TYPE SECTION The type locality of this sub-stage is on the Colorado river, in the extreme western corner of Fayette county. "White Marl Bluif at Shipp's Ford, near the county line be- tween Fayette and Bastrop counties, forms the final fossilifer- ous exposure of the Cook's Mountain beds. The railroad bridge crossing the river two miles north of West Point rests upon an excellent exposure of the chocolate clays and sands of the Yegua with its characteristic sideritic concretions. The first high bluff down the river from this location was called by Penrose Chalk bluff from' its color. The base of this bluff is made up of beds belonging to the Yegua, but higher up a different formation comes in which is character- ized by light colored sands and joint clays which belong to the Fayette. Criswell creek just east of "West Point gives excellent expos- ures of the Yegua-Fayette contact. The uppermost Yegua in this locality is a chocolate sandy clay splotched with yel- low and containing plant remains. The basal Fayette is a '■ First Annual Report Geol. Sur. of Texas, p. 47. The Geology of East Texas 135 white sandstone, rather fine grained, with a few yellow ferru- ginous markings. Overlying this sandstone are white sandy shales with yellow ferruginous sand laminae. The difference between the two formations is striking. Not only are the colors distinct, but the lignitic or carbonaceous matter so prevalent in the Yegua is missing' entirely in the lower Fayette and the siderite or limonite concretions are re- placed by a few knobs of ferruginous sand. The Fayette beds are well shown, in Pine Bluff, which is at the sharp bend of the Colorado at west end of Old River, about four miles northeast of West Point. At this exposure there is at the top 70 feet of gray and white sand interbedded with white and watery green clay. This is underlain by beds of similar clay alternating with thin seams of lignite and with chocolate clays. Penrose's section is as follows : 1. Quaternary drift. 2. Interbedded gray and white sand, white and watery-green clay 70 ft. 3. Hard water-green clay, like in (2) 4 ft. 4. Lignite 2 It. 5. Similar strata to (2), light chocolate color on surface 3 ft. 6. Lignite 1 ft. 7. Similar strata to (5) 7 ft. 8. Chocolate clays, with black leaf and reed impressions % ft. 9. Hard watery-green clay 4 ft. 10. Lignite 1 ft. 11. Hard light green clay , 5 ft. 12. Similar strata to (8) V2 to 1 ft. 13. Hard, light green clay 6 ft. 14. Lignite 1 to 2 ft. 15. Hard, light green clay 10 ft. Gates ' Bluff, two and a half miles east of Pine bluff gives the top of the Fayette and its contact with the Jackson. At this place a bed of lignite is just at top of water level in river. It is overlain by ten feet of interbedded clayey sands, shaley to thin-bedded, with some carbonaceous streaks and is strongly jointed. Its top is an old land surface and the section shows a line of silicified stumps standing upright and evidently in place as they grew. Between them are pot-holes filled in with the 136 University of Texas Bulletin darker sands of the overlying impure lignitic band, which is here taken to be the base of the Jackson. No marine fossils were found in the Fayette beds, but leaf impressions were seen in abundance, and gypsum and sulphur were present in nearly all the beds. Nowhere in the Colorado section were any sands seen which appeared to- represent the Wellborn beds. All of the sediments apparently referable to the Jackson belong to its lignitic and fresh water phases, and are presumably later than the Welborn, which seems wanting in this section. EIO GRANDE SECTION As in the ease of the Yegua, the Rio Grande section gives a clearer idea of the charac1;pr and fossil contents of these beds. While the sediments are largely of marine deposition on the Rio Grande, the materials entering into them are similar to those of 'the Colorado section. The Rio Grande beds may be divided into two parts. The lower part extends from Zapata to the northern line of Starr county and is made up of greenish clays and sands interbedded .with buff sands with some calcareous matter and greensands. These beds are very fossiliferous. The upper part, extending from the Starr county line to Roma, while not differing so much lithologically from the lower, has a larger proportion of the buff sands and its only fossil seems to be the very large oyster called by Penrose Ostrea geor- giana, but identified by Harris as 0. alabamiensis var. contracta of Conrad. The fiirst exposure of the Fayette beds in the Rio Grande region is described by Dr. Penrose as follows : "Four miles above the Texas town of Carrizo, and on the Mexican side of the river, is seen a bed of woody lignite 1% to ft. thick, over- lain by 10 ft. lof buff sands and underlain to the water's edge by 4 ft. of greenish-gray clay. The Rio Salado flows into the Rio Grande from the Mexican side opposite Carrizo. The town of Guerreno is on this river 6 miles from the mouth, and in this distance are seen many outcrops of buff sandstone, often rising in abrupt ledges through the Geol. S. "W. Texas, pp. 37-8-9-40. The Geology of East Texas 137 river alluvium. Most of the houses, churches and fences of the town are built of it." At Carrizo the beds yielded the following fossils: Lacinia alveoata, Con. Ostrea alabamiensis var. oontracta, Con. Similar exposures are seen just below Carrizo, wliere the river runs more nearly in the strike of the beds. After it again turns southeast the blnff sands iorrn low bluffs for 2 or 3 miles, when we find, on the Mexican side of the river, in a long, low line of exposures, a .cireenish, sandy clay, partly indurated, but variable, with harder green concretions, which are more or less calcareous. Here we found : Lacinia alveata, Con. ; Voluiilithes petrosus, Con.; CornuUna armigera, Con.; CytJierea iastropensis, Har. ; Tellina mooreana, Gabb. A similar exposure, just below, on American side, was a mile or more in length, and showed many undulations. This was in turn succeeded by exposures of buff sandstones, which here seem to dip about 6 degrees to the SE. This condition continues to the mouth of a small creek just north of Rancho Ramireno, which ' ' cuts through a series of low bluffs, ledges of interstratified buff sandstones containing gray con- cretions and septaria, and chocolate, black and greenish-blue, semi-indurated clays, dipping 1 to 2 degrees southeast." The forms identified by Prof. Harris are: Ostrea contracta, Con. ; Conus sauridens, Con. ; Volutilithes, sp. ; Venerica/rdia *planicosta, Lam. ; Semele lienosa, Con. ; CytJierea bastropensis, Har.; Lacinia alveata, Con. var.; Pseudoliva vetusta, Con.; Natica recurva var. diimblei. Thei'e is a I'ossililerous l-iyer near the mouth of the creek and forming its bed. This shows a mass of shells much comminuted. The few specimens wheich we found entire had, doubtless, weathered from the softer buff sands, as we found them in place in that material. These clays and sands are highly colored, and as usual show considerable cross-bedding. In the drift we found many beautiful agates, chalcedony and petrified wood — which here made its first appearance on our trip. The buff sands and interbedded materials form a reef below the mouth of the creek and continued down the river several miles, when a bluff was lO-ET. 138 University of Texas Bulletin found on the Mexican side which showed "interbedded hard and soft, calcareous sandstones and clay seams," and containing Volutilithes petrosus, Con., Turritella nasuta, Gabb, ; Lacinia al- veata, Con.?; Anomia ephippioides, Gabb; Leda opulenta, Con.; Venericardia planicosta, Lam.; Tellina mooreana, Gabb; Cy- therea hastropensis, Ear. Numerous calcareous concretions are found, and the sand oc- casionally contains coarse, black and gray siliceous grains the size of mustard-seed and larger. Just below the mouth of Tigre creek there is another exposure of the buff sandstone and its interbedded clays and sands, with grayish, limestone concretions of all shapes and sizes. Some of these concretions seem to contain masses of decomposed iron- pyrites only, but the most of them are fossiliferous. In the buff sandstone we find only specimens of oysters, all other forms being confined to the concretionary beds or particular masses. Some of these contain all their fossils (except oysters, which remain as shells) simply as rusty casts, while in others all the forms are fairly preserved. Among these are: Venericardia planicosta, Lam.; Turritella nasuta, Gabb; VolutUitJies petrosus, Con.; Crassatella rotexta, Con. var. ; Cytlierea hastropensis, Har. ; Pseudoliva vetusta, Con. ; Conus saiiridens, Con. ; Cornulina armigera. Con. var. A very short distance above the Zapata-Starr county line there is a long exposure, on the Mexican side, of bluish-gray clays, capped by a bed of fossiliferous greensand. The next exposure, however, is again of the buff sandstone, with very large concre- tions, and showing a distinct synclinal structure. In appearance,^ it closely resembles the materials of the Fayette beds on the Col- orado river, north of LaGrange. Then follows the bluff, of which Dr. Penrose gives the following section: 1. Indurated, light-brown sand 3-6 ft. 2. Loose, light-brown sand 10 ft. 3. Gray clay 5 ft. 4. Oyster-bed. Ostrea alalximiensis var. contracta 1 ft. 5. Gray clay 1 ft. 6. Oyster-bed 1 ft. 7. Detritus to water's edge 4 ft. In this section the oysters, some of which are a foot or more The Geology of East Texas 139 in length, occur not only in the oyster-beds, but scattered through the buff sands also. Two miles below, the beds are still more clayey in their nature, as is shown by the following section made at Las Guerras bluff, the point at which the river makes its sharp turn to the northeast, 5 miles or more west of Roma: 1. Greenish-yellow clays, indurated, thin-lDedded, and carrying gypsum and sulphur ' ... 20 ft. 2. Oyster-reef. 0. alaiamiensis, var. contracta, 1-2 ft. 3. Calcareous bed 1-2 ft. 4. Buffl clays, partly indurated. Oysters 8-10 ft. 5. Bright-colored, sandy clays,, with gypsum, sulphur and lig- nitic' matter '• 8 ft. 6. Very hard sandstone, bedded and banded in brown, yellow and red colors 12 ft. The gypsum in No. 1, of above section, was of yellow color, and occurred in seams %-inch thick, .and in crystalline masses of considerable size. I suspect that this bed will be found to be the base of the Frio clays, since my notes state that its dip is only 4 degrees, while that of the calcareous and underlying beds is about 7 degrees. The lower beds are referred to the Fayette on the strength of the persistence in them of the large oyster, which has been used as one of the characteristic fossils of this sub-stage. The buff sands continued toward Roma, and the oyster-reef, with the same large oyster, was seen in the river-jbank at that town. One mile below, however, where the final exposure of the buff sands was observed, no oysters were found. Between the Colorado and the Brazos, the Fayette was found along Nails creek north of Ijedhetter overlying the Yegua and underlying the fossiliferous "Wellborn sandstone of the Jackson. MAPPED AREA Bast of the Brazos river the Fayette has been found only in detached bodies overlying the Yegua north of the Jackson border. These are simply remnantal portions left by an erosion interval which separated the Middle froln the Upper Eocene. The Fayette does not appear along the Sabine river. The most easterly area recognized was a mile southwest of 140 University of Texas Bulletin Huntington, Angelina county, on the Texas & New Orleans Railroad. A hill on the Renfroe place which rises twenty-five feet above the surrounding Yegua clays is made up of a light- gray quartzose sandstone ranging in consolidation from a hard sandstone to a well indurated quartzite. Some four miles west of this locality there is a larger area surrounding the town of Homer. This town is underlain by a light bluish-gray, cross-bedded sandstone. North of the town, it changes to a white sandstone of medium grain, evenly bedded, and is moderately hard. It is quarried for local use. To the southward the sandstone is overlain by light cream- colored clay, thin-bedded to massive and showing cross-bedding in places. About one-fourth mile north of Homer, at the head of a small creek, is the first exposure noted. Here there is about 2^^ feet of black surface loam, containing much carbonaceous ma- terial and very much resembling a poor grade of peat. At the base of this loamy material there is a thin layer of gravel, made up of fragments of silieified wood, ferruginous clay-stone, quartz, and quartzitic material, all of the fragments being sub- angular to rounded. Below this is a brown limonitic layer about six inches thick and made up of hard, concretionary limonitic clay. This member of the section was found to occur only in a few places. Underlying and forming the base of the section is a white to cream colored clay, sometimes, when damp, dull gray, hard, compact, fine-grained, which breaks with a semi-conchoidal fracture. This clay is jointed and in the joints a black carbonaceous material resembling lignite occurs. It evidently has washed in 'from the overlying loam. Little could be seen of the bedding of the clay, but in some places it seemed to be thin-bedded, while in others it was more massive- with cross-bedding showing in a freshly broken piece. Going down the creek, the clay outcrops along the banks and makes up the creek bottom. In one little gully the clay is ex posed to a thickness of five feet and several four foot sections were noted. In no place, except at the east .and west ends of the deposit, could the bottom of the clay be seen. Here it was seen to rest unconformably upon a gray, thin-bedded sandstone which tilted locally at an angle of about 2& degrees. The clay TKe Geology of East Texas 141 was unconformable on this sandstone in all respects as regards dip, and the plane of contact was found to be much warped. The clay thinned out to the east and west, which showed that the deposit was of a lenticular nature. In an east-west direction this deposit extends for about 2000 feet. To the north and south its extension is not very well known. Two similar areas occur along the line of the Houston, East & West Texas Railway. One of these is north of Burke, the other southeast, extending almost to the Jackson contact. The hill north of Burke is about three miles long north and south. The northern end is made up of a gray to white sand or sand- stone, and a measured thickness of 20 feet was observed. The sandstone is thin-bedded in places, and varies locally from soft to hard. Pieces of silicified wood are found in the sand- stone, which is fine-grained throughout. Lamination planes can be seen in the apparently massive, well indurated material. Some of the beds are up to one foot thick. The topography here is gently rolling. On top of the hill a log of silicified wood was found, which was about 25 feet in length and 2^4 feet in diameter. On this low hill near Burke, is an exposure of grayish-white, soft sandstone with blotches of black material. The quartz grains are rounded and the black blotches seem to be due to some kind of stain on the quartz grains. About one-fourth mile farther north on side of hill is found a thin-bedded, green- ish-gray, shaly clay with partings of grayish sand. In the sand small shining crystals resembling selenite were found. On the west side of Jacks Bayou, just east of Blix, in Ange- lina county, there is a ridge of sandstone of light gray color. The ridge is 20 feet in height, and a well 50 feet deep found only the same sand. The rock is a fine grade of very light gray sandstone, with medium-sized quartz grains and grains of magnetite. It is medium hard and lies in layers of about one foot in thickness. Suman found an isolated outcrop of similar rock at Huston Park, one and a half miles southeast of Alto, in a hill rising about 75 feet above surrounding country, which contains about 60 feet of a hard, indurated, massive, white to gray, or cream- 142 University of Texas Bulletin colored sandstone. This material does not resemble any other encountered in this vicinity, and is hard to account for. Litho- logically, it seems to resemble the Payette sandstone as ob- served near Burke, but no fossils were seen. There is a ridge running for about three miles through the country that is capped by this rock. Baker considers this a remnant of the Fayette, ' which indi- cates that in this region the Fayette originally not only over- lay the Yegua, but overlapped upon the Cook's Mountain beds. To the west of the localities described, there are other areas of the Fayette which are similarly related to the Tegua and the Jackson. Three of these are found along the Houston- Trinity county line northwest of Groveton, and in the vicinity of Pennington. The description of one will serve for all. On the north side of Bast Prairie on the farm of Mrs. BlufE- ington on the D. Ashworth Survey, two miles north of Penning- ton, there outcrops a fine-grained gray to whitish colored sand- stone varying in hardness from soft to almost that of a quartz- ite. It contains an abundance of .a black mineral resembling magnetite in small specks. It varies from massive to cross- bedded and very locally may be thin-bedded. Near the top of the hill there is 8 feet of the harder rock outcropping over about five acres. The rock varies rapidly in this area from hard to soft. It is underlain down the hill by ten or twelve feet of cross-bedded, fine-grained, soft, white sandstone. In the creek bed below this there outcrops some lignite. The sand- stone is used locally for building chimneys. West of the Trinity similar exposures are found along Bedias creek north of the Yegua-Jackson contact as far west as the northeast corner of Grimes county. The Fayette has not yet been certainly identified on the Brazos, owing to the presence in that vicinity of the Wellborn sandstone of the Jackson, which has been confused with it. Whether both are present here, or whether the Fayette was entirely eroded before the deposition of the Wellborn, has not been determined. That the two are separate and distinct sands is fully proven by their general character and fossils. The Fayette in East Texas consists. of very light colored sands and clays with some lignite, and only plant remains as fossils. The Geology of East Texas 143 The Wellborn is predominatingly a brown sand with remains of marine invertebrates. There are no materials in any of the Jackson beds east of the Brazos corresponding to those of the Fayette inliers in the Yegna which have been described. The stratigraphic relations are such that the two could not belong to the same horizon. CLOSE OF THE CliAIBORNE At the close of Claiborne deposition, the sea again receded, thereby adding a broad belt of land to the growing terrane of the Coastal Plain. How far this recession may have reached is unknown, but the indications are that the period of the reces- sion was not as great as that between the Lower and Middle Eocene. In ^ast Texas this recession was accompanied by an eleva- tion of the beds which, while extending from the Sabine to the Brazos, attained its maximum east of the Neches. This is indicated clearly by the fact that the Fayette beds, which are normal on the Colorado, begin to show erosion west of the Brazos, on which stream they are doubtfully present, and east- ward are only known by remnantal areas to the Neches drainage, beyond which they are entirely unknown. In this area not only has the Fayette been entirely removed, but the underlying Yegua has also been scored. While a large portion of this erosion must have taken place during the interval between the recession of the Claiborne sea and the transgression of the Jackson, it is possible that a part of it belongs to that period of the early Jackson in which 'the Wellborn beds were laid down between the Brazos and the Trinity-Neehes divide. The greater erosion eastward, however, was in all probability due to greater elevation above sea-level. Veatch finds evidence of a post-Claiborne movement in con- nection with the salt dome at Winfield and there are indications of similar movement around the Palestine dome. These movements evidently had their beginning in the Sabine region during the Marine, as is shown by the conditions at the base of the Nacogdoches in the type locality. It was the move- 144 University of Texas Bulletin ment beginning then which changed the shore line of the Clai- borne sea from the northeasterly trend which it had had in common with the Midway sea and with the waters of the Wilcox to the east-west line which has prevailed east of the Neclies river from that time to the present. University of Texas Bulletin No. 1869 Plate VII. Fig 1. FAYETTE FORMATION. Near Homer, Angelina County. w» s'i^-i^'"-ii Fig. 2. JACKSON FORMATION. Cross bedded sandstones on H. E. & W. T. R. R. Mile Post 100. Chapter VII JACKSON Name Conrad found at Jackson, Mississpippi, a series of deposits which carried a large and well preserved fossil fauna which was intermediate in age between the Claiborne and Vicksburg, and which he described and called the Jackson. The beds are described as calcareous marls and lignitiferous clays, but later descriptions add a bed of siliceous sands at the top. In the bluff at Yazoo City, 180 feet of the calcareous clay is exposed. It carries crystals of gypsum and many marine fossils in addition to bones of the Zeuglodon which characterize the Jackson of the embayment area. The entire thickness in Mississipppi is estimated at 350 to 450 feet. The marine fauna of the Jackson has been found to contain nearly as many species as that of the Claiborne, and, although the number common to both is comparatively small, they are of Eocene types and the formation is considered to be. the upper- most division of that series. The discovery of the Jackson in Texas was due to Harris and Veatch'', who found and recognized Jackson fossils in the vi- cinity of Corrigan, on the Sabine, and in material gotten from an oil well at Sour Lake. Later, Vaughan, on the basis of a restudy of the fossils found near Wellborn, referred the "Wellborn sands to the basal Jackson, but it was left for Baker and Suman to work out the extent and character of the beds referable to this horizon lying between the Sabine and the Brazos. General Character A>fD Thickness. The Jackson, like other divisions of the Eocene in Texas, while made up largely of marine deposits, has also its share of those Crider, Bui. U. S. Geol. Sur. 283, p. 35. ' Louisiana Geol. Sur. 1902, p. 25. 146 University of Texas Bulletin laid down in lagoons and swamp areas. In some regions, in fact, it is the principal lignite-bearing formation. In addition to these deposits, which it has. in common with the underlying Claiborne, it is especially characterized by terrestrial deposits and by ma- terials derived front volcanic flows and eruptions. The lowest beds are fossiliferous sands and clays. These are followed by calcareous clays and sands, also fossiliferous, lignitic sands and clays, beds of volcanic ash and other materials of igneous origin, and some limestones and sandstones. , Of the sandstones, some are quartzitic in character and some have a porcellaneous cement. The fossils of the sandstones are largely casts, but in the clays they are well preserved. Zeuglodon bones were found at one or two localities. The Jackson is distinguished by the fact that in it the clay ironstone and limouitic concretions of the underlying Yegua are replaced by calcareous concretions and by a greater propor- tion of sands and sandstones. Some of the Jackson sands are very hard, even quartzitic, but are always light gray in color and are fossiliferous in places. Volcanic ash beds are also character- istic. The top of the Jackson is placed where the chocolate lam- inated clays and carbonaceous sands give place to coarse "rice" sands or sandstones and yellowish green, structureless clays and claystones. These beds, have a thickness in Angelina county of between 400 and 600 feet and are probably thicker on the Trinity, and to the west of that stream. Distribution The outcrop of the Jackson on the Sabine has a width of about four miles. As it strikes westward, it gradually becomes wider until it reaches the divide between the Neches and the Trinity in the vicinity of Groveton. In this region it attains its maximum surficial width, which is about eighteen miles. The belt then strikes soiithwestward, crossing the Trinity west of the town of Trinity. The outcrop on the river along the line of dip narrows to five miles. Between the Trinity and the Brazos it has an aver- age width of eight to nine miles and crosses the latter stream southwest of Wellborn. TJie Geology of East Texas _ 147 Disposition and Relation to Underlying Formations So far as can be determined from the contacts we have seen between the Claiborne and the Jackson, the newly emerged Mid- dle Eocene sediments which formed the surface of the coastal fringe at the beginning o£ the Upper Eocene showed little change in condition in the vicinity of the Colorado. The Jackson sea, coming in from the southward, in the vicinity of the Brazos, transgressed the Claiborne land to the northeastward rather slowly at first, but more rapidly later. The basal or Wellborn sands and their overlying lignitic deposits are well developed on the Brazos and eastward to the Trinity river. These basal de- posits, however, do not extend beyond the divide between the Trinity and the Neches rivers. From the Neches eastward these sands are replaced by the medial or Caddell clays, which form the basal beds" between the Neches and the Sabine. Between the emergence of the Claiborne and the deposition of these basal beds the greater part of the Payette east of the Brazos was removed by erosion arid in consequence the Wellborn sands are in immediate contact with the Yegua between the Brazos and Trinity, while east of the Neches the contact is between the Tegua and the Caddell clays. The Yegua shows an eroded sur- face at the contact at some localities, as at Mile Post 659 on the Missouri, Kansas & Texas Eailway. In this area, therefore, the Jackson began with the. marine con- ditions on the Brazos and land in the east. The marine condi- tions gradually extended to the Sabine and were succeeded to the. westward by those which permitted the deposition of lig- nitic beds. Finally, littorat conditions prevailed along the en- tire front. During the period there were volcanoes in active eruption. Some of these were probably located to the seaward of our area, while others were within the region now occupied by its sedi- ments, and furnished volcanic tuff and ash for its beds. To this source is also due tlie large amount of opaline matter now occur- ring as opalized wood and as the porcellaneous cement of the many sand beds. 148 University of Texas Bulletin Subdivisions At the base of the Jackson we find sandstones of rather fine grain, gray and brown in color, interstratified with lignitie clays and sands and overlain by sandy carbonaceous shales carrying silicified logs. These are the "Welborn beds, and are followed by greenish clays and sandy clays with calcareous concretions and greensand, and other clays with gypsum and sulphur. They have been called the Caddell beds. West of the Groveton divide these clays are also lignitie and not fossiliferous. The upper member consists of a series of lignitie clays and sands with which are interbedded brown sandstones, some of which have a por- cellaneous cement while other are quartzitie, the uppermost portion being carbonaceous sandy clays with gypsum and sul- phur. These are called the Manning beds. In connection with the Caddell beds and continuing up into the Manning we have extensive beds of volcanic ash and some volcanic tuff. COERBLATION WlTH OtHEE ArEAS Kennedy found a number of fossils in the sandstones of Wil- liams Quarry on the Stephenson League three miles east of Well- born, which Harris identified as follows, classing them as Lower Claiborne. These were found near the base of the sands : Yoldia claibornensis Venericardia planicosta Cy.therea bastropeasis Siliqua sinrondsi Mactra sp. a Corbula alabamlensis Turritella sp. Cancellaria penrosei Pleurotoma Quassalla Cylinchna kellogii Deussen made f uther collections in this vicinity and says^ : "Vaughan is of the opinion that the horizon represented by the hard fosiliferous sandstone of the section on the Robert ' Water-Supply Paper 335, p. 72. TJie Geology of East Texas 149 Stephenson League is probably very low in the Jackson. ' ' He does not enumerate the fossils, but as he probably had a fuller collection than that which Harris examined and as the Wellborn is apparently the continuation of the sands forming the base of the Jackson to the east, the Wellborn sands are re- moved from equivalency to the Fayette, as was formerly held, and placed at the base of the Jackson. The fossils of the Caddell clays which occur on Tar Kiln creek four miles northwest of DiboU are well preserved and represent an horizon considerably higher than the Wellborn. The only Zeuglodon bones found were in connection with the Caddell. The Manning sands which overlie these contain many imprints of fossils, mostly lamellibranchs, but they are somewhat poorly preserved. It is probable that when the present collections are properly studied it will be found that practically all of the Jackson time is represented in our section. Details of Section brazos and grimes counties Wellborn: — Kennedy^ describes these beds as follows: These sandstones, with their accompanying gray sands, al- though here tentatively denominated the Wellborn beds, belong to and help to form a part of, the series of gray sands and sand- stones extending across the State from the Neches river in Polk county as far west as Sunnyside church, in Lee county^. In Grimes county these beds have been narrowed down to a belt occupying an irregular area lying between the calcareous sands and sandstones of the Navasota beds and the underlying dark gray sands and lignites of the Yegua group, and appear only as isolated patches. In Brazos county the gray sands and sandstones form an ir- regularly defined belt of varying width extending across the county from the edge of the Navasota bottom lands on the east to the Brazos river on the west. They are hard, close-grained. fourth Annual Report, Geol. Sur. Tex. p. 45. ' Probably not Wellborn, but Fayette. 150 University of Texas Bulletin and compact, occasionally showing a tendency to become quartz- itie. The country occupied by them is generally flat and prairie- like, covered by gray sand, and few outcrops of continuous ledges of the sandstone can be seen anywhere. Small outcrops occur at several places on the Sam Davidson and James Hope leagues, on the western side of the county, where the belt has an apparent width of nearly three miles. These outcrops are irregular in areal extent and thickness, and appear usually as isolated patches or "knobs" surmounting the small rounded hills forming the uplands of this region. The sandstones here rest upon the upper beds of the lignitic sands and clays found farther north. A section on a small creek on the south side of the James Hope headright shows: 1. Gray sand and gravel 1 ft. 2. Gray sand, with great quantities of silicified wood 5 ft. 3. Gray indurated sand, witli ledges of soft sandstone 10 ft. 4. Gray sandstone, jointed and thinly bedded : . . . . 8 ft. .5. Dark brown lignitic clay, showing yellow streaks and sulphur efflorescence 20 ^t. Near the mouth of White 's creek the gray sandstones are seen capping the higher grounds. Here these rocks are arranged in three ledges, showing an aggregate thickness of 20 feet, and rest upon the dark brown clays of the lignitic deposits. No fossils have been obtained from them, except a few small dicotyledenous leaves, but their direct continuity with the fossil-bearing sand- stones has been traced along a series of small outcrops across the county by way of Minter Springs and Wellborn to the junction of the two on the E. Stephenson league. Going east from Wellborn, light gray laminated sandy clays and thin beds of sandstones appear in the cuttings and washouts along the south side of the R. Stephenson league for a distance of several miles. About three miles to the southeast of the sta- tion, at Dr. Williams' quarry^, on the same league, an exposure of regularly bedded gray sandstones appears along the north bank ' Thia is locality from which fossils were collected, the list of which was given in connection with the correlation of these beds. The Geology of East Texas 151 of a small stream. The general section at this place appears to be: 1. Gray sands, showing some distance down the cre^....2 to 8 ft. 2. Thinly laminated, light gray (almost white) sandy clays 2 to 8 ft. 3. Broken deposit of sandstone, containing fossils 2 ft. 4. Regular and even bedded gray fossiliferous sandstone 6 ft. On the Brazos river Kelly found what he considers the hase of the "Wellborn in a bluff just north of Koppe's bridge west of Wellborn. His section shows: 1. Dirty brown clay with a layer of dark brown limonitic con- cretions five feet from base. Fossils at base 1& tO' 20 ft. 2. Brownish-gray, fossiliferous clay, showing limonitic layers 1-16 to 1-4 inch thick. Toward top it contains beds of sand 1-inch thick 6 ft. 3. bignitic clay interbedded with yellow clay. Some limonite concretions. Balls and lenses of lignite showing manga- nese in cracks. A few light to dark gray concretions of siderite 4 ft. 4. Interbedded sands and clays. Beds of clayey sandstone mark the base of this section. The layers are one to' three inches thick, well bedded, poorly indurated, coarse to medium greensand, color dirty white to greenish white. The middle is more argillaceous, whiter, thin-bedded, with layers of lignite an Inch thick. The upper 3 feet more sandy, thin- bedded and showing stains of limonite. Silicifled wood Is plentiful In these beds 10 ft. Members one and two are probably "Wellborn. A mile and a half south of Batte's ferry, he found the fol- lowing : 1. Thinly bedded sand and sandstone, some beds colored deep yellow by iron. Bedding very thin, but persistent. Nodules of pyrite are present 3 ft. 2. Very soft sandstone with fine laminations, yellow to reddish brown in color 1 ft. 3. Interbedded white sands and dirty gray shales. Sands in beds less than 1-inch thick, breaks In flags and rings when struck • • • • ' 2 ft. 4. Blue, fine-grained sandstone, poorly indurated 1 ft. Below this some two miles, Penrose found : 152 University of Texas Bulletin 1. Cross-bedded, gray sand, hardened in places 10 ft. 2. Hard greenish clay, -with seams of chocolate clay.. 12ft. 3. Lignite »•..-■ 1 *'*■ 4. Hard greenish clay •. 6 ft. 5. Lignite • • ^ ft. 6. Calcareous, gray sand, with indurations 6 ft. Dip of the strata 1 to 5 degrees soiath. Many imperfect leaf impressions and considerable amounts of iron pyrites are found in the elay^ These beds probably belong to the Caddell clays, which are also shown in a section on the river five miles west of Millican and one mile above the mouth of Boggy creek, as follows : 1. Thin-bedded, fine-grained sandstone, dirty -white in color and locally stained with limonite. Silicified tree trunks 6 in. 2. Massive yellow sandy clay, weathering bluish white 3 ft. 3. Sandy clay with small flakes of sandstone 10 ft. 4. Interbedded sandstones and lenticular sand beds 3 ft. 5. Loose, cross-bedded, coarse to medium grained sandstone with clay band at top and bottotn • • . . 1 ft. 6. Medium grained, massive sands 3 ft. 7. Light yellow sandy clay, white siliceous scale partings.... 7ft. 8. Lignite 9 in. 9. Light green clay, weathers to powder 1 ft. 10. Lignitic clay 6 in. 11. Light green <:lay like (9) 9 ft. 12. Fine and coarse grained, gritty clay, weathing into Irregular fragments 5 ft. 6 in. 13. Volcanic ash bed. In places pure ash, cross-bedded, in others mixed with clay; has lenses and one small bed of lignite; pyrites 15 to 20 ft. The Manning beds were not identified in the river section, but the contact between the Jackson and Corrigan occurs about one mile above the Santa Fe bridge. The base of the Jackson crosses the Houston & Texas Central Railroad at lola. In the barrow pit, extending south from Bridge No. 143.04 of the Trinity & Brazos Valley Railroad, the following section is exposed : 1. Laminated, gray-brown and greenish-gray to light brown sandy shaly clays 10 ft. 2. Gray brown, soft, shelly sandstone stained with iron and in places taking on a reddish-brown color 4 ft. The Geology of East Texas 153 This section is very probably of Jackson age and represents the northern limit of that formation in this Ticinity. From this point south all of the cuttings are in the Jackson, until we get about 23 miles south of Singleton. The cutting one-half to three-fourths of a mile south of lola exposes 10 feet to 15 feet of a yellowish-gray to light greenish- brown structureless, somewhat sandy, ball clay. -It weathers out a dirty, gray-brown, and has calcareous nodules in places near the surface. These nodules are, however, very scarce. The ma- terial is more sandy, locally, and a soft, fine-grained, gray sand- stone may be noted in places. This sandstone shows up better just south of the cut. About one mile north of Grimes Station the following section is exposed, dipping 1° S. 60° E.: 1. Gray-brown, lamjnated and shelly sandstone, fine-grained, and varying from soft to hard, the whole being much stained with iron 8 ft. 2. Laminated, gray and gray-brown, fine-grained sands 3% ft. The dip flattens out towards the middle of the cut. The sec- tion is covered by a dark, reddish-brown clayey soil. The section is typical Wellborn. In the barrow pit 10 to 25 feet below Bridge No. 136.82 these shelly and laminated to thin- bedded gray sandstones still continue. Immediately north of Grimes a cutting exposes the following section : 1. Yellowish-brown clay, containing gravel and petrified wood. .2-3 ft. 2. Cross-bedded, medium grained, gray sandstone, for the most part soft and stained brown on the surface 4 ft. 3. Brick red clayey layer, probably formed by water acting on No. 4 3 In. 4. Laminated, sandy, chocolate brown shaly clay 8 in.-l ft. In the gray sandstone, large pieces of petrified wood are to be found. These beds all belong to the "Wellborn. MADISONVILLE BRANCH SECTION The Tegua-Jackson contact on the Madisonville branch of the International & Great Northern Railway comes in the bot- ll-ET. 154 University of Texas Bulletin torn of Big Bedias creek. Loose, fine-grained, brown Wellborn sands 3 feet thick occur in a cut half way between Mile Posts 35 and 36. A section in a cut one-third mile north of Mile Post 36 exhibits the following: 1. Shelly bedded, light brown, very friable, clayey sandstone . . 6 ft. (Contact between (1) and (21 not seen.) ■ 2. Very light gray, coarse grained sand with angular fragments of flint. The lower 1 inch to 1 foot is irregularly indu- rated and contains small masses of white clay 1 ft. 3. Light brown sandy ball clay ^ 5 ft. 4. Light brown, shelly bedded sandstone. Passes into loose creamy laminated sand to the north along the strike.... 2ft. At Mile Post 35 is 4 feet of light brownish cream clay carry- ing volcanic ash and very similar to the clay exposed on the Missouri, Kansas & Texas Eailway between Willard and Grove- ton, in Trinity county. Locally, there are thin white shelly layers of claystone. When at all consolidated it is thinly laminated. Underlying it in downward succession .are, (1) very light gray, loose, thinly laminated, medium grained sand 3^^ feet thick; (2) compact, light gray-drab ball clay stained with sulphur and limonite, much jointed and broken into small frag- ments, 2 feet thick. One-half mile north of Mile Post 34 is 6 feet of white im- perfectly bedded volcanic ash mixed with coarse angular trans- parent quartz sand. Between Mile Post 34 and Bedias thin, shelly-bedded, light- brown sandstone outcrops. In a cut one-fifth mile north of the 34th mile post is the following section. 1. Thin, shelly-bedded, light brown sandstone. 2. Medium grained, light gray-brown, very friable sandstone with leaves 2 ft. 5. Thinly and irregularly laminated nodular light brown sandy clay 8 tt. 4. Laminated brown and gray sand 3 ft. 5. Chocolate-brown carbonaceous shale with thin interbedded layers of gray sand In middle 1 tt. The two basal layers have a dip of 6° south, or a little east of south. Silicified logs with veins and incrustations of hyalite are found in the section. The Geology of East Texas 155 About 2-3 miles some south of west of Bedias along a high ridge, overlooking South Bedias creek bottom to the south, there outcrops a sandstone of medium to fine grain and of vary- ing degrees of hardness. In places the sandstone is white in color and tends to be soft. In others it is bluish gray in color and indurated to a c^uarzite. The matrix of the sand grains is in places of an opaline nature, in others it is fine granular, and the color is for the most part white or gray, but local discolora- tions to yellowish-brown and reddish-brown occur. This sand- stone has been prospected extensively along the ridge and pits are to be found in it everywhere. The greatest thickness that could be measured from' these was 5 to 6 feet. The rock mass is probably from 25% to 30% quartzite. On this same ridge about 2% miles south of west of Bedias on the lola road the sandstone is found locally to be packed with fossil casts. The fauna includes gasteropods, as well as lamellibranchs. Venericardia planicosta is very prominent, to- gether with a Cyfheria, Turritella and a fusiform east. While this material is apparently identical with that found along the Houston, Bast & West Texas Eailway two miles north of Cor- rigan, Polk county, it belongs to the basal or Wellborn beds and corresponds to the Stephenson League locality. From the 32nd to the 27th mile posts there are shallow ex- posures of the characteristic brown shelly-bedded Jackson sandstone, quite friable, with more massive friable sandstone 1 foot thick. At the 27th mile post are light, greenish-yellow, clayey, fine-grained', unconsolidated sands about 3 feet in thickness. The topography is a very gently rolling, dissected peneplain. One-third mile south is brown, irregularly lami- nated clay 1 foot thick, underlain by 2 feet of greenish-brown drab, waxy-lustred clay, much fractured and plastic. The following section is at Mile Post 26: 1. Dark brown, sandy loam with Lafayette-derived pebbles and silicified wood fragments '. 4 ft. Unconformity: 2. Brown sandy shale, locally partially indurated 1 ft. 3. Greenish-brown drab, much fractured, plastic clay 4 ft. 4. Brown shale 3 in. 156 University of Texas Bulletin 5. Dark brown carbonaceous shale 6 in. 6. Brown shale 3 ft. The characteristic weathering color of the Jackson is dark, reddish-brown. Southward in the alDove section a bed of dark- brown, carbonaceous shale 1 foot thick is found in No. 3, arched in the shape of a low anticline 100 feet across and 4 feet high, which to the southward dips beneath the surface. This carbonaceous layer lies between two layers of No. 3 and is equivalent to No. 5. Below No. 6 is a layer 3 feet in thick- ness similar to No. 3. Still farther south, 100 yards north of Mile Post 26, .No. 5 again appears at the surface in a low anticline. These clays are apparently a part of the Caddell beds. One-half mile to the west is an old pottery works. Here 4 feet of shelly-bedded, brown, sandy shale is overlain by the same thickness of cream-colored, cross-bedded, contorted bedded and thinly laminated, volcanic ash. The section is un- eonformably overlain by dark gray sandy loam 1-2 foot thick with Lafayette-derived pebbles and fragments of silieified wood. One hundred yards upstream the volcanic ash is over- lain by 2 feet of brown carbonaceous shale. The Manning beds in this section are first found at Mile Post 25 as a brown, cross-bedded sand 5 feet thick, locally ease-hardened and with a much fretted surface, which is over- lain by four inches of dark gray, sandy loam, with Lafayette- derived pebbles and fragments of silieified wood. At Lorimer siding the above mentioned bedrock section is overlain by light- brown, poorly laminated clay 2 feet in thickness. One-third mile south of Mile Post 25 is the following section. 1. Dark brown soil, residual and alluvial with Lafayette-derived pebbles and wood fragments 2 ft. Unconformity: 2. Light gray, clayey sand with white calcareous nodules 3 ft. 3. Gray, cross-bedded fine sand 3 ft. Light gray, medium well indurated sandstone, weathering brownish, 3 feet thick, is exposed one-fourth mile north of Singleton. Wells at Singleton penetrated 10 feet of lignite at The Geology of East Texas 157 depths approximating 50 feet. There is a parting of brown carbonaceous clay at a depth of 8 feet below the top of the bed. The lignite has a roof of rather hard sandstone about 13-16 feet thick. The water af Singleton is very poor. One-fifth mile south of the Singleton station, exposed in cuts on both the International & Great Northern and Trinity & Brazos Val- ley railroads, is light gray, cross-bedded, medium-grained sand 2 feet thick. Associated with this, is very light gray, or cream colored, volcanic ash cemented on fracture planes by light gray opaline silica, giving the rock a breeciated appearance, the fragments of white powdery ash, being 1-8 inch or less in diameter. At Mile Post 23 the ash, which is here thin- bedded and gritty, while the ash 200 yards north is not appre- ciably gritty and is finer, is underlain by brown, shelly-bedded sand and sandstone 2 feet thick. The contact between the Jackson and Corrigan is found be- tween the 23rd and 22nd mile posts. From the Madjsonville branch to the Trinity river the Yegua- Jackson contact follows the course of Bedias creek, which fiows about one mile south of the line between the two forma- tions. TRINITY RIVER SECTION The Trinity river affords one of our best sections of the Jackson. Its most northern exposure on this stream is found about one-fourth mile north of Calhoun's Ferry, at the corner of Madison, Houston and Walker counties. Here indurated Wellborn sandstone forms two large rapids, with an estimated combined fall of at least 6 feet. The rapids are formed by massive medium-grained, opaline-cemented, light gray sand- stone. Interbedded with this is the usual "shelly," brown, clayey sandstone. The sandstone contains many carbonaceous leaf imprints. The lower fall has a 4 ft. drop over a ledge of sandstone at least 6 feet thick. Overlying the sandstone is a foot of lignite, overlain unconformably by blue-gray and brown mottled, sandy, alluvial clay. Just above the upper shoals, second bottom terraces are present on opposite banks of the river. Natural levees, sometimes 10 feet in height and form- 158 University of Texas Bulletin ing very perfect embankments, are found along the Trinity. Alluvial deposits extend from Calhoun's Ferry almost to Kit- trell on the Calhoun's Ferry-Trinity road. The Jackson is found on this road just south of Dillard's creek. The section at Calhoun's ferry follows. The dip at this ex- posure is from 21/2 to 4% degrees to the southward. This ex- posure is on the "Walker county side, or the north bank: 1. Light brown, clayey, alluvial sand. Gravel at base, whicli forms terrace at the north end of the blufC 10 ft. Unconformity : i. Shelly-bedded, dark, grayish-brown clay, sandy and yellow- stained In middle, with plant fragments. Poorly consoli- dated 15 ft 3. Lignite, impure, with carbonaceous clay. Lignite of poor quality. Upper seam of greenish, waxy clay. Forms shoal in river 5 ft. 4. Dark brown, shelly clay at north; farther south changes to plastic, slickensided, greenish-brown clay . . ■ ■ 1 1-4 ft. 5. Lignite, good quality, dull lustre, forming shoal in the river 4.5 ft. 6. Light greenish and yellowish-green joint clay, waxy and non- plastic, with black oxide of manganese. Laminated, sandy, cross-bedded, and with carbonaceous fragments in middle. Weathers light gray to cream colored. Upper 3 feet darker when un weathered than the lower portion 7 ft. 7. Sandy, gray clay, poorly laminated, with plant fragments . . 2 ft. 8. Poor lignite and blackish, carbonaceous shale 1.5 ft. 9. Hard, firm lignite, locally burned 2.5 ft. 10. IJght brown sand, with carbonaceous fragments % ft. 11. Light greenish, fine-grained sand, pyritlferous and sulphur- ous, thinly and irregularly laminated 6 ft. 12. Light gray sand, fine-grained, micaceous, irregularly and shelly-bedded, much jointed, with small black fragments of Salix and other leaves 2.5 ft. 13. Dark gray-drab clay, jointed and imperfectly laminated 5 ft. 14. Chocolate-bPown, carbonaceous, sandy clay 1 ft. 15. Pine-grained sand, thin and irregularly laminated, yellow- ish-stained light gray, with thin plates of dark brown carbonaceous matter and small lignitic fragments 7 ft. 16. Dark greenish-gray, laminated, joint clay with lignitized fragments, and with irregular lenses of fine light gray sand. Sand locally in irregular pockets with cross-bedded The Geology of East Texas 159 ■structure. Weathers grayish and light brown and oontains lignitized fragments. Sand in upper half 15 ft. 17. Dark greenish-gray, sandy, sticky, joint clay, mainly sand in upper half Y f t. 18. Dark brown, carbonaceous clay with lignitized fragments. . 1 ft. 19. Lignite 1 ft. 20. Dark gray, fine-grained sand, clayey, thinly laminated 2 ft. Total of Jackson in this section is 86 feet. One-fourth to one-half mile below the end of the above bluff is the following section: 1. Irregularly laminated sandy clay, yellow-stained brown 7 ft. 2. Hard, firm, dull-lustred lignite with thin lenses of brown carboneaceous . clay. Lignite makes shoals 2 % ft. 3. Dark brown, carbonaceous shaly clay 1 ft. 4. Laminated, gray, fine-grained, yellow stained sand 3 ft. 1. Grayish-brown, carbonaceous, shelly sandstone 5 ft. 2. Laminated, sulphurous, chocolate clay B ft. 3. Like (1) and sulphurous 4 ft. 4. CpoBs-bedded, loose, gray sand, fine-grained. Laminated and more indurated at the base. Locally indurated to a fine- grained, thin-bedded sandstone 25 ft. 5. Poorly laminated and shelly sands, somewhat clayey, highly sulphurous and carbonaceous. Gray brown in color 12 ft. 6. Sandy clays and sands, dark brown to black, highly carbo- naceous and sulphurous, poorly laminated. Lignitiferous. Locally contains sandy pipe concretions 8 ft. The bluff here is 63 feet high, measured with hand-level. The sandstone carries fairly good plant fragments and casts of marine lamellibranchs were noted on one piece of sandstone on top of the bluff. The sandstone also shows selenite flakes. In almost all of these bluffs streams with exceedingly steep sides are to be found. These are canyon or gully like in form. At Weiser's Bluff, springs highly charged with sulphur issued from the bottoms of the gullies. Just below Weiser's Bluff, in a stretch where the river flows N. 30° W., there is a bluff on the Walker county side which exposes some 60 feet of Jackson. Here there is no perceptible dip. At the base is JO feet of bluish-gray, laminated, shaly clay, overlain by grayish-brown, shelly sands, 40 feet in thick- ness, and this is covered by 10 feet of gray sandstone. 160 University of Texas Bulletin Cincinnati Bluff, about one mile downstream from Weiser's Bluff, is also on the Walker county side, .and is slightly higher than Weiser's Bluff. The section at Cincinnati Bluff is very similar to that of Weiser's Bluff, except that the upper 15 feet is composed of light reddish terrace material. About 4 feet of lignite is exposed in a shaal on the south bank of the river just above" the mouth of Wright's creek. Just below the mouth the following section is exposed on the north bank: 1. Alluvium with calcareous nodules, light brown in color, but blackish towards top 20 ft. 2. Lafayette-derived gravel 2 ft. Unconformity: 3. Light brown, shelly, sulphur-stained, clayey sand l%,ft. 4. Impure lignite 2/3 ft. 5. Light brown, gray, laminated and cross-bedded carbonaceous sand 10 ft. One-half mile below the mouth of Nelson creek there is a rock shelf on the south bank which juts out into the water and rock shoal extending across the river with a 4 ft. fall. The follow- ing is the section : 1. Brownish, irregularly laminated and "shelly" clayey sand.. 10 ft. 2. Lignite . . • • .• ; 3 ft. 3. Indurated gray sEuidstone layer forming rapids 1 ft. 4. Irregularly, cross-bedded and laminated sands 6 ft. No perceptible dip was noted in this section. The bed of lignite and other strata of the above section outcrop upstream continuously to slightly above the mouth of Nelson creek. The next shoal downstream is made by lignite. At the base of this exposure is thinly laminated, gray, carbonaceous sand 3 feet in thickness, locally partially indurated into irregular surfaced shelly sandstone. Above is dense black lignite 2 feet in thickness, with top ol the bed not seen. One-fourth mile farther downstream, the next shoals exposed 3 feet of thin, shelly-bedded, brown, carbonaceous sandstone. The next ex- posure one-half mile downstream is situated on the south bank like the last two. The section is: TJie Geology of East Texas 161 1. Light brown, sandy clay with, whitish calcareous nodules, dark gray on the surface — alluvium 20_25ft. Unconformity : 2. Light grayish-brown, clayey sand, poorly laminated, carbo- naceous 6 ft. 3. Dark brown, carbonaceous shale, forming a fairly good roof for the lignite 6 ft. 4. Lignite, non-lustrous, not waxy, much weathered, varying in thickness, light in weight 5 ft 5. Sandy, dark brown, carbonaceous shaly clay with many black plant fragments ■ • 3 ft. Below the above section, at the east end of the bluff, is the following section. The dip here is 2° S. 70° W. 1. Laminated sand, like basal member of section last given. 2. Poor grade lignite 1 ft. 3. Brown carbonaceous sand 1 ft. 4. Gray, thinly laminated violcanic ash, sandy and carbonaceous 3 ft. 5. Volcanic ash, very fine-grained, cream-colored, laminated. .2-5 ft. 6. Brown clayey sand, highly sulphurous and carbonaceous. shelly ... I 3 ft. 7. Shelly brown sandstone 3 ft. 8. Brown clayey sand 3 ft. At the east end of the bluff the lignite is overlain conform- ably by a layer of Lafayette-derived gravel. One-half mile downstream, on the south bank, is another bed of lignite. The section here is : 1. Light brown, sandy, alluvial clay with calcareous nodules. 2. Limonite-cemented layer of Lafayette-derived gravel. 3. Brown carbonaceous, imperfectly laminated sand 7 ft. 4. Dark brown, shaly clay, sandy, firm, carbonaceous and highly sulphurous 2 % ft. 5. Dense, dull black lignite 5 % ft. 6. Shelly, compact, sticky dark brown carbonaceous clay, with lignitized fragments • % ft. 7. Laminated blue sand, cross and contorted bedded, and with layers and lenses of blue clay, pyritiferaus 5 ft. The dip here is 2° West. This exposure is opposite the mouth of Dillard's creek. The partially indurated sand be- neath the lignite forms shoals. 162 University of Texas Bulletin At the bluff 2 miles south of the town of Trinity the Thomp- son Brothers Lumber Company have a pumping plant. This bluff is about one-half mile long and affords quite the finest exposure of Jackson yet seen. The dip is 2l^° to the south- east. The section is: 1. Alluvial sandy clay with, calcareous nodules, mainly light brown in color, but is greenish-gray near the surface at a short distance from the river 25 ft. 2. Lafayette-derived gravel layer. Unconformity: 3. Thin and shelly-bedded, brown and gray sand 15 ft 4. Massive, fine-grained gray or brown sand, loose, imperfectly laminated or cross-bedded locally 11 ft. 5. Chiocolate-brown, sandy clay banded towards top and of drab color. Thin-bedded and laminated. Contains one 5 ft. drab, clayey sand layer about 8 feet above base. The upper portion is very sandy and well stratified 16 ft. 6. Clayey, brownish, sulphur-stained, shelly-bedded sands Clayey layers, dark gray in color. Some of the sands are also cross-bedded and of gray color. Contains lignitized stumps with marks of borers 31 ft. 7. Lignite l'2"-2 % ' 8. Dirty-green, sticky clay, locally oopp eras-stained 4 ft. 9. Lignite 2 % ft. 10. Dirty-green clay, unctuous, much fractured 2 ft. 11. Dark blue-gray, medium-grained sand, laminated 3 ft. 12. Dark greenish-gray, compact clay with plant fragments weathering light gray 2 ft. 13. Dark brown, sandy, carbonaceous shale 11 ft. Total Jackson exposed in above section 100 feet. A bed of lignite outcrops in a low bluff on the west bank, one-half mile below Clegg's shoals. This bluff trends east and west along the strike of the beds. The same bed of lignite outcrops on the east bank about one-half mile farther down- stream, where the dip is one degree or less in a southward or southeastward direction. The section is: 1. Yellowish, sandy alluvium, generally with Lafayette-derived pebbles at base. Unconformity : 2. Laminated, medium-grained brownish sands. TJie Geology of East Texas 163 3. Lignite, hard, firm, dull lustre, semi-conchoidal fracture.... 4ft. 4. Brown sand, carbonaceous, locally clayey 4 in. 5. Lignite 6 in. 6. Dark gray, carbonaceous clay 4 i:t. 7. Laminated gray, medium-grained sands, contorted and cross- bedded 6 ft. The next two exposures farther downstream are about 2 miles distant from each other. They consist of 15 feet of thinly lami- nated light gray, fine sand. The upper exposure has 2 thin seams of carbonaceous matter within 4 or 5 feet of the top. It is folded in broad, very low waves with one abrupt vertical downfold of 2 ft. in the same horizontal distance. The lower exposure is lo- cally stained with yellow, has slightly contorted bedding and is overlain unconformably by 2 feet of ferruginous cemented La- fayette-derived conglomerate. A bluff two miles north of Riverside and about 200 yards west of the International & Great Northern Railway may present in its basal member, the upper part of the Jackson formation and the contact between it and the overlying Corrigan. INTERNATIONAL & GREAT NORTHERN RT. SECTION There are few exposures of the Jackson on the International & Great Northern Railway. On the line between Trinity and Houston counties the base of Jackson shows thin, irregular and shelly-bedded, friable, creamy to buff sandstones. There is 8 feet of volcanic tuff exposed just north of Mile Post 16, with its base not seen. When pure this tuff is of a light yellowish-cream color, but when mixed with sand it is grayer. The whole is much cross-bedded, with sharp planes of demarka- tion between beds dipping at different angles. Another pecu- liarity is small ellipsoidal bodies of very fine clay or tuff in- cluded within the main deposit. The plane between beds dipping in different directions are flat or irregular surfaced. Another peculiarity is the cross-laminae in which coarser grains form lighter-colored laminae, interbedded with laminae of darker Francisco. The purity of these ash beds would naturally lead gray, finer materials. This deposit is almost certainly of eolian origin. It duplicates almost exactly sections of sand dunes to be seen south of the Presidio and near the Cliff House at San 164 University of Texas Bulletin one to the conjecture that they must be wind-blown deposits, and the cross-bedded stj-ucture of this exposure renders the view rather certain. The volcanic ash is overlain a short distance to the south by poorly indurated, medium-grained, gray sandstone, locally mottled. Tyler and East Prairies, northwest of Groveton, are in reality one large prairie with a narrow neck of timber reaching across near the middle. Together they approximate six miles in an east-west direction by 2% to 3 miles in a north-south direction. The surface of the ground on these prairies is very rolling and they do not present the smooth surface noted in other prairies to the east. For the most part the prairies are well drained by shallow, broad gullies emptying into Little White Rock and Louisville creeks. The town of Pennington is situated about the middle of the prairie, near the south line of the Prado League, Trinity county. Near the central northern end of the prairie a deep gully cuts into the underlying formations and the following section is ex- posed : 1. Surface sand and soil of the prairie, a gray sand for the most jjart containing abundant gravel of red color and large size, together with large l)lo«ks of petrified wood 2 to 3 ft. 2. Cross-bedded clayey sands of varying thickness and often missing from section. Petrified wood 2 ft. 3. Limoriitic concretionary layer 2 in. 4. Drab clay, somewhat sandy, weathers out whitish about the same as No. 6 except that No. 6 is somewhat stained with iron 3 ft. 6 in. 5. Yellowish-brown, limonitic, concretionary layer, for the most party very continuous 2 to 3 in. 6. Yellowish-brown to drab sandy clay, with layers of gray sand, sometimes 1-16 of an Inch thick. The clay is gypsiferous and tastes of alum. Weathers out whitish 2 ft. The materials of the section above given weather along the gully in badlands form. No dip was noticed.' These beds are near the base of the Jackson. The wood found in No. 2 of this section was identified by Berry as Cladas'porites fasciculatus Berry, which is found in both Claiborne and Jackson beds in the Coastal area. While it is certain that the sections as given between the The Geology of East Texas 165 Brazos and central Trinity county contain deposits which are the equivalents in time of the Caddell clays, the mottled gray and brown fossiliferous clay with fossiliferous limestone nodules which constitute these beds eastward from the divide between the Trinity and Neches rivers are entirely absent, being replaced by lignitic clays and sands. GROVETON SECTION The relationship of the three stages of the Jackson are found in the Groveton section which was made along the Groveton, Luf- kin & Northern Railroad between Apple Springs, where we found the top of the Yegua, and Groveton, and on Caney creek south of Groveton. The first section south of Apple Springs shows: 1. Sticky,, bluish gray clay co-ntaining sandy ferruginous con- cretions In places 1 % t't. 2. Clayey sand, massive, grayish tO' light brown, fine-grained, gypsiferous 2 It. Cutting 2200 feet north of Mile Post 15 exposes the following : 1. Thin bedded, gray to white and light brown sandy clay and shaly clay, similar to No. 4 5 ft. 2. Highly carbonaceous clay, or poor grade lignite chocolate -, brown in outcrop 6 ft. 3. Gray, thin-bedded to miasslve, slightly gypsiferous sand 10 ft. 4. Dark chocolate brown shaly clay with noi visible structure, except near the top, where thin bedding is seen. Con- tains sulphur along joint planes 8 ft. The third member is made up of even-grained small rounded clear quartz pebbles stained slightly with iron. Dip of beds in direction S. 25° E. is from 1° 20' to 2°, being higher in northern end of cutting. Between 800 and 2000 feet north of Mile Post No. 14 the fol- lowing section is exposed: 1. Light brown clayey sand 5 ft. 2. Thin bedded, fine-grained, gray sandstone alternating with a laminated mauve sandy shale, slightly gypsiferous 7 ft. 3. Massive, fine-grained, sandstone, gray in color 2 ft. 166 Univet'sHy of Texas Bulletin i. Thin-bedded, light brown, slightly carbonaceous, sandy shale, containing local incrustations of a gypsiferous nature 25 ft. The fourth member contains large fragments of silicified wood having a dull earthly lustre. Dip on the second member measured at S. 25° W. was 1° 20'. This member in the north end of cut grades into a slightly carbonaceous sandy clay, dark brown in color. Covering all is a thin veneer of quartzitie gravel. At Mile Post No. 15 the fourth member is seen to carry a hard ferruginous layer about three inches thick. Near Mile Post No. 12, a section of 4% feet shows alternating bluish-gray, laminated, shaly clay and dark red ferruginous sandstone about equally developed in layers averaging 9-inches thick. Cutting 800 feet north of Mile Post No. 11 (Alabama creek) exposes about 8 feet of a light brown and bluish-gray, sticky sandy clay containing numerous rounded limestone concretions which are up to 2 feet in diameter. These concretions are fos- siliferous and a collection, mostly casts, was made. Among the genera might be mentioned : Cardita, Leda, Dentalium, Natica, Turrit ella and numerous other gasteropods and lamellibranchs, in addition to a species of coral, which belong to the Caddell clays. Cutting 1750 feet south of Mile Post 9 exposes the following section : 1. Brown surface sand up to 1 ft. 2. Dark gray toi black sandy clay, mottled reddish brown in places 1 ft. 3. Yellowish brown to brown clayey sand containing gravel, but pebbles are of noticeably smaller size, although of same material as (4) 3 ft. 4. Yelowish brown clayey sand containing quartzitie pebbles and fragments lof silicified-wood. Pebbles are rounded and of all sizes from 1-8" to 2" in diameter 3 in. 6. Light brown to chocolate brown, carbonaceous shaly clay containing leaf impressions 5 ft. At Mile Post 8 and immediately to the south there is a cutting exposing about 10 feet of a chocolate brown, carbonaceous shaly clay, thin bedded, and containing leaf impressions. Near the middle of the section is 3 inches of a grayish to yellowish brown cross-bedded sandstone. Some few tiny flakes of selenite show The Geology of East Texas 167 upon the surface of sand partings in the clay. At Mile Post 8 the clay seems to butt up against 3 feet of gray, highly cross- bedded sandstone. Limonitic concretions, oval in shape, and with a concentric structure, were observed scattered through the section. Immediately north of the bridge over Piney creek (Bridge 7.32) there is a bank about 20 feet high which exposes a very good section as follows. 1. Brown carbonaceous, thin-bedded shale 4 ft. 2. Medium grained sandstone, much cross-bedded. Irregularly interbedded with a thin-bedded sandstone and a. sandstone bedded in layers up to 4 inches thick 7 ft. S. Alternating beds of medium grained, rather soft, yellowish brown to gray sandstone and a grayish brown, carbo- naceous, fine-grained rather hard sandstone, successive lay- ers being about 2 inches thick 4 ft. To the south of Caney creek (Bridge 4.75) about 100 yards and on the eastern side of the track, there is a low ridge running down to the track. It is made up of a very resistant, fine and even grained, gray sandstone. The sandstone is made up of small rounded quartz grains with a matrix of a quartzitic nature. The sandstone is very hard, breaks with a splintery fracture, and contains large fragments of silicified wood. The silicified wood has a dull earthy lustre and the grain shows up very well. This ridge does not rise more than 5 feet above the surrounding country and the rock is only seen exposed over a limited area. Near the section house about three quarters of a mile north- east of Mile Post No. 3 the following section was observed : 1. Yellowish brown sand containing quartzitic pebbles, rounded and up to 2-inches in diameter 1 ft. 2. Mottled dark bluish gray and reddish brown clayey sand . . 3 ft. 3. Gray, rather hard, even grained and rather fine-grained, cross-bedded sandstone 2 ft. In the creek bottom the gray sandstone is seen to be thin- bedded and cross-bedded and to contain thin layers of choco- late brown clay containing fragmentary plant impressions. Just north of junction of the Groveton, Lufkin & Northern Railroad with the Missouri, Kansas & Texas Railway, one mile 168 University of Texas Bulletin northwest of Groveton, is a cutting exposing 5 feet of .a highly cross-bedded, even grained, gray sandstone overlain by about 4 feet of brown sand carrying many quartz pebbles up to 1% inches in diameter. Cutting one-eighth mile north of the above section exposes at the bottom 5 feet of the gray, even grained sandstone which is locally cross-bedded, thin-bedded, or massive, and contains in some places limonitic concretions, while in others a slight yel- lowish brown mottling is noticed. At one point the sandstone contains angular fragments of volcanic tuff up to 2-inches in diameter. Clay nodules are contained in the sandstone and also in the overlying sand which covers the sandstone to a depth of 5 feet. The sand here is yellowish brown to gray in color and carries quartz pebbles. Three miles east of Trinity, on the Missouri, Kansas & Texas Eailway at the crossing over White Rock creek, there is an exposure in the creek bottom of about 1 foot of a white, soft, volcanic tuff, underlain by at least 3 feet of a calcareous soft, stiff clay, which is irregularly bedded and mottled chocolate brown and gray. This material is carbonaceous and fragments of wood were found in it. Immediately overlying the tuff is a layer of gravel about 6 inches thick, and the whole is covered by about six feet of gray sand. Up the creek, and oh its eastern side, about one-fourth mile from bridge there is a bluff rising about 80 feet above the creek made up mostly of a gray, rather resistant, even and fine- grained sandstone, containing a few casts of fossils. This rock stratigraphieally overlies the tuff. The top of the hill is covered by a quarzitic gravel made up of rather coarse pebbles of quartzose and chalcedonie material. In one place, about one-fourth mile east of the bluff, gravel was seen to a thickness of 7 feet and was being excavated for local use. This high bluff extends up the river for two miles. Carrying the section southward along creeks south of the Mis- souri, Kansas & Texas Railway, some two miles southwest of Westville on "White Oak creek, the following section was ob- served : Thin-bedded, laminated and wavy, cross-bedded, clayey sands and sandy clays grading in places into only slightly are- The Geology of East Texas 169 naeeous clays. The colors are for the most part grayish and brownish, but all graduations from yellowish to buish or drab were seen. This material weathers honey yellow locally, but in most places weathers yellowish-brown. Contains abundant organic matter in shape of leaves, stems, etc. The dip here was in one place 2 degress to the south. This dip is believed to be local. A hill 70 feet in height with a summit area of 2i/2 to 3 acres is found in the bottoms of Dean creek. The creek flows along the northern and northeastern base of this hill. In the bed and banks of the creek is found the following section : 1. (a) At the south, directly under the northeast base of the hill, there is 12 feet of thinly laminated brownish to buff sand carrying thin streaks of brown carbonaceous material, but becoming sandier and thicker bedded toward the top. The bedding here is also slightly irregular. 1. (b) At the north, along the creek banks is exposed 10 feet of thinly laminated, light brown to drab 'sandy clay carrying plant fragments. The bedding is not very regu- lar and the individual beds aje not of uniform thickness. At the eastemm'ost locality examined the beds dipping 3-1-2° to the southward, 50 yards south the dip is 8° to the southward, while 100 yards south of the latter locality, the dip Is apparently 4 or 5 degrees to the westward, but this apparent dip may have been caused by slumping. 2. Dark brown, carbonaceous clay, gradually becoming lighter with a lessening in the amount of carbonaceous matter towards the top 1 ft. 3. Lignite, poor in quality 1 ft. 4. Base, dark brown carbonaceous clay, total thickness unknown. Above the bed 1 (a) the surface of the hillside is strewn with blocks of sandstone. A rim of sandstone in place surrounding the top of the hill is in places a massive bed 3 to 4 feet thick. Locally, these sandstone blocks are quartzitic; in places they exhibit imperfect lamination and break in blocks thick enough to be suitable for dimension stone. The sandstone contains thin flakes of selenite and much of it case-hardens on the sur- face on exposure to .air. About one-half mile above the A. Wicker Survey there is ex- posed 5 feet of medium to fine-grained gray sands poorly lami- nated and cross-bedded, the same being clayey in places. These 12-ET. 170 University of Texas Bulletin sands dip 2° S. 20° W. and they are underlain in the creek bed by chocolate shaly clays. On the A. Wicker Survey there outcrops a fine-grained, gray sandstone containing casts of lamellibranchs and also showing ripple-marks. The fossils are probably brackish-water forms. The sandstone is underlain by 2 feet of lignite coal and this in turn is underlain by black, carbonaceous clay. One-half mile belowthis place there is exposed 6 feet of choc- olate colored, shaly, sandy clay with layers up to 2^^ inches thick of gray sandstone. Much fossil wood was collected along this creek. For the first half mile upstream from the Beaumont & Great Northern Railroad bridge, on the east bank of White Rock creek and below mouth of Caney creek is the following section: 1. Grayish brown, fine-grained, fairly compact sandstone, In some places in one large layer and in other places in sev- eral layers, full of plant remains, mainly Palmetto 4 ft. 3. Yellowish and brown laminated sandy clay stained with sulphur and limonite 12 ft. Above ths was found opaline-cemented sandstone resembling that of the Catahoula, and the beds are practically the top of the Jackson in this region. The plant remains from these beds identified by Berry are as follows : Caney and White Rock creeks, 6 to 10 miles east of Trinity : Uppermost Jackson at Corrigan Contact Other Gulf States. HiygiO'dium mississippiensis Berry Catahoula Sabalites vicksburgensis Berry Vicksburg Catahoula Dryophyllum n. sp. Claiborne Anona texana Berry Myrcia catahoulensis Berry Catahoula Apocynophyllum n. sp. Claiborne Jackson HOUSTON, EAST & WEST TEXAS RAILWAY SECTION Tarkiln creek flows into the Neches about four miles north- west of the Houston, Bast & West Texas Railway crossing of that river. Suman found on the Hobbs Survey exposures of a mottled-brown and bluish-gray, sandy and highly gypsiferoua The Geology of East Texas 171 clay containing Eocene fossils in a fair state of preservation. Locally, the clay contained limestone concretions with concen- tric structure and these contained an abundant fauna of lamel- libranchs, gasteropods and corals. A good collection was made. This material resembles very much that found on the Groveton, Lufkin & Northern Railroad 800 feet north of Mile Post No. 11 at an elevation of 300 feet. The following forms were iden- tified : Ostrea c. f. contracta Telllna sp. Area sp.? Turricula sp. Venericardia planicosta Lam. Bulinella kellogii Gabb Venerioardia rotunda Lea Turritella nasuta Gabb Peetunculus idoneus Con. Turritella houstonia Har. Pectunculus sp.? Solarium alveatum Con. Crassatella texana Hellp.? Solarium huppertzi Har. Crassatella flexura Volutilithes petrosus Corbula alabamiensis Lea Cassidaria sp. Oorbula oniscus? Calyptrea sp. Cytherea tOTnadonIs Har.? Dentalium dumblei Har. Tellina mooreana Plabellum wailesii Oon. In the yellow, sandy concretions are many large Pinna, PJiol- odomya, EcMnoderms, small Haminea grandis, etc. The exposure on rail line in south bank of Neches river shows the lignitic clays and sands of the Caddell. There is a succession of clays and sands, brown to grayish-brown in color, apparently massive in places, but for the most part laminated or shaly. The clay breaks into nodular pieces. It grades into more or less sandy clay and is interbedded with laminated lignitic sands. A band of lignitic material is overlain by cal- careous sandy beds which carry numerous impressions of lamel- libranchs. The clays are overlain in the vicinity of Fant by massive, cross-bedded sands which are apparently unconformable with them. Just south of Mile Post 100 these sands are in turn succeeded by sandy shales which also seem unconformable on the Fant sand. In these shales there are bands of volcanic ash, and by the side of the road there are several opalized stumps standing upright in the ash with their roots spread into the shales underlying as though in situ. The trunk of one of these has a diameter of twelve inches and is solid. Another is 172 University of Texas Bulletin twenty inches in diameter with .a hollow center. It was partly rotted before being buried and the opalization filled the joints and hollows. The Fant sands carry some siliceous gravel and the shale has a few ferugiaous concretions. Baker's section here is as follows: 1. Much cross-bedded, light cream colored sand containing irregular, non-continuous lenses and layers of light drab clay. The lenses and layers of clay have curved, irregular outlines and lie in the sands often at attitudes a.t vari- ance with the horizontal. The sand is medium-coarse in grain and sub-angular to ro-unded in contour. Some of the seams and lenses of clay are dark brown from the included carbonaceous matter. The sand shows imperfect lamina- tion, which lamination effect is aided by thin layers stained with sulphur and llmonite. At the south end of the cut there is at the top about 2% feet of thin-bedded, light cream sandy clay alternating with thin layers of light brown, much like the clay at Potomac (Mile Post 99). Maximum thickness 15 ft. Unconformity with irregular contact, suggesting the erosion of a channel before the deposition of the overlying beds. 2. Nodular, sandy clay, light brown in color, weathering to a light buff ior a light drab, sulphurous. Locally carbo- naceous about 1 foot above base. Upper 10 feet of light buff color. Thickness varies, up to 20 ft. 3. Thin-bedded, unconsolidated, light 'brown sandstone with small dark, drab clay nodules and thin irregular lenticular layers of clay with thickness up to 1-4". Irregularly stained with sulphur and limonite. Carries also brown plant frag- ments and locally exhibits case.hardening with a light pur- plish-blue tinge 12 ft. In the gully immediately to the south of this cut is exposed a maximum of 27 feet of the light drab, sulphurous, sandy clays unconformably overlain by light gray to cream colored, cross- bedded sands similar to those described under (1) above. At the north end of the cut at Mile Post 100 small grains of tuff (?) were mingled with the quartz grains. These sands are locally indurated and then are light bluish or purple-gray in color. The induration is irregular and gives a nodular aspect to the rock. The spaces between jointed blocks are seamed The Geology of East Texas 173 with the cementing material and these seams standing out as ridges give a cavernous or honeycombed appearance to weath- ered surfaces. It is only the top layers from 1 to 2 feet in thickness which are so indurated and locally some of the over- lying gravel of the surfieial member has also been cemented. The surfieial indurated layer projects over the underlying less resistant sands. The induration follows the contour of the present surface and the indurated zone is a broad low dome in shape. In the vicinity of Mile Post 100 cross-bedding is very greatly developed. At the extreme south end of this cut, near the road crossing, there is exposed at the track level 1 foot of very fine white ash with base not seen. This ash is locally indurated on the surface exposures. Some of the cross-bedding, especially at the south end of the cut, with planes meeting each other at abrupt angles, suggest either a sand dune, a bar or spit, or the downstream side of a river "towhead." Between Mile Post 100 and Mile Post 99 sands similar to those at Mile Post 100, and locally case-hardened, are exposed. In the cutting about one-fourth mile north of Potomac, on the Houston, East & "West Texas Eailway, the following sec- tion was noted : 1. Case-hardened, Indurated, perhaps calcareous-cemented, light gray to light cream colored sandstone weathering in cavern- ous or large honeycomb form and dontaining in the sur- fieial layer, in situ, rounded pebbles of Quartzitic and gra- nitic rocks. Massive. Thickness 1 ft. 4 in. 2. Friable, fine-grained, somewhat cross-bedded sand with sel- enite flakes. Color is light cream to light brown 3 ft. In both members were noted small clay balls and fragments of what resembled volcanic tuff. The matrix here may be tuff. The general dip of the lower member was southward at low angle. This surfieial member (No. 1) may represent re-ce- mented, both residual and transported material, .and may be- long to the Lafayette. The cementation of this member is ir- regular and it shows a tendency, locally, to be more indurated, along joints, which gives it the cavernous .appearance. Locally it is compact and is a medium hard sandstone. In the creek bed immediately west of Houston, Bast & "West 174 University of Texas Bulletin . Texas Railway, about 200 yards north of signal board "Poto- mac," there outcrops a stratum of lignite 3.5 feet thick, which burned in the camp fire. On exposure to the air' it slacks. The stratum is covered by about 4 feet of chocolate colored, shaly clay and two feet of surficial material. It is black in color, of light weight, and breaks with an irregular fracture. This ma- terial outcrops along the creek for a distance of about 60 feet. Cutting in creek bed immediately northeast of signal board "Potomac" shows 8 feet of a light cream colored sandy clay, case-hardened and standing with vertical walls. It is gypsifer- ous and slightly carbonaceous, often containing leaf imprints. The material shows imperfect lamination and locally it may be stained yelowish brown by limonite. The sand in this clay is very fine-grained. Section exposed 1000 feet south of Potomac shows 3 feet of medium grained sand, gray and yellowish brown to cream col- ored, thick bedded at bottom of exposure, but grading into- thin-bedding and lamination at top. Covered by 3 feet of a chocolate brown, highly carbonaceous clay, sandy locally. This^ is in turn covered by about 1 foot of gravel. The sand member is clayey locally and contains mud balls. About 300 feet farther south the sand member is exposed up to 3 feet and is- finely laminated and cross-bedded. Contains plant remains. At Bridge 99-C, 7 feet of the sand member is exposed in the- creek bank. Locally, it contains sandy clay layers and layera of chocolate brown, carbonaceous, shaly clay up to 1-8 inch thick. The dip here is 3° S. Three hundred and fifty feet north of Mile Post No. 97 the- following section is exposed: 1. Lafayette. Light mottled reddish brown and gray, locally, and dark brown elsewhere, sandy clay. Contains much gravel made up of quartz, chalcedonic and metamorphic pebbles and small angular blocks of a hard sandstone, probably derived from a local source. Large siliceous wood fragments up to 2 feet in length are found' here too. Case- hardening on surface g ft.- 2. Fine, dark brown clay 2 ft 3. Laminated, fine sand, light gray to light brown and contain- ing plant fragments and tiny flakes of selenite 3 ft.. TTie Geology, of East Texas 175 An excellent collection of marine invertebrate fossils in a fine state of preservation was made from well dug about 200 feet west of Bridge 96-C along the Benford tram. These shells came from a, blue clay at a depth of 28 feet. A very interesting locality is that on the northwest corner of the J. M. Deane League, Trinity county, about 5 miles due west of Potomac. On the northwest corner of this League, near the Trinity county line, in the bed of Rocky creek, the following section is exposed : 1. Chocolate colored, laminated shaly clay 2 It. 2. Thin-bedded, soft, gray to yellowish brown sandstone con- taining casts of fossils, both lamellibranchs and gasteropods I'ft. 3. Alternating thin-bedded chocolate to drab shaly clay and yelloiwish brown sand 1 ^/i ft. 4. Gray to white clayey sand standing with perpendicular walls. Contains abundant poorly preserved lamellibranch shells for the most part of only about three species 8 ft. 5. Cross-bedded!, coarse, dark gray and bluish gray angular grained sand. Some few green giuins resembling glau- conite were seen in this sand. Locally almost a shell marl and locally contains lignitized wood. Shells of Ostrea abundant in places 3 ft. 6. Greenish blue, shaly clay, thin-bedded and massive and grad- ing locally into chocolate brown colored clay. Contains many fairly well preserved lamellibranch remains 3 % ft. Approximately one-half mile below the above locality there is a hill rising about 50 feet above the creek, on the eastern bank. It is capped by a white sandstone containing a few easts of fossils. Locally, the sandstone is indurated to a quartzite, but for the most part it is of medium hardness. Some few leaf impressions were noted. The material underlying this sandstone, found outcropping in the creek bed, is a buff clayey carbonaceous sand underlain by laminated drab to chocolate colored shaly clay with parting of yellowish brown sand. In the creek bed were picked up teeth and spines of sharks and rays Synecodus, Odontaspis, etc., scutes of a marine turtle and fragmentary limb bones of small mammals. From this locality there was also collected a jaw fragment of what 176 University of Texas Bulletin was possibly a creodont carnivore. A good collection of marine invertebrates was secured here. MANNING SECTION The section in eastern Angelina county is similar. The Caddell clays with fossils are found at Donovan. Between Donovan and Manning chocolate clays with gypsum and sal- phur-buff compact, unctuous clays and dark clays with limo- nite are found. Shawnee prairie is three miles north of Manning. The prairie is covered with a good growth of grass and is said to be good farming land. The clay underlying the prarie is very gypsif- erous. The following is the section of the clays underlying Shawnee prairie: 1. Light chocolate brown, plastic clays containing sulphur and fibrous gypsum, stained with reddish and brownish limo- nite on joint planes. Contains numerous casts of Bocene fossils, among them a, large Pinna, also yolutilithes, Venericardia, Gorhula texana, and several other lamel- libranchs and gastenopods. These casts are found in the clays and in thin sandy layers, in some places well lami- nated and medium well indurated. 10 ft. 2. Light bufE, compact unctuous clay often breaking with a conchoidal fracture. Stained yellowish brown on joint planes with limonite. Weathers cream colioired 6 ft. The upper member is the base of the Manning beds. The rocks exposed in the gullies in the lower portion of Man- ning are gypsiferous sands and chocolate clays with plant frag- ments. These two rocks frequently alternate in thin beds. In some of the sands are small fragments of fibrous pumice and a light greenish clay directly overlying this tuffaeeous sandstone under the bridge west of the church contains some fine ash. In cutting about 100 yards southeast of the depot at Manning there is exposed about 3 feet of a dark gray to brown, irregularly thin-bedded sandstone containing casts of fossils. The casts occur in a layer near the bottom of the section and quite a few of the same forms found in the cutting at Mile Post 101-G on the Hous- ton, East & West Texas Railway were recognized. In these "shelly" bedded sands are often found clay inclusions in the University of Texas Bulletin No. 1869 Plate VIII. "^•^i^&g Fig. 1. JACKSON FORMATION. Volcanic ash on White Rook Creels, Trinity County. v^ •• t,- \ Fig. 2. JACKSON FORMATION. Volcanic Ash 2 miles east of Corrigan. TJie Geology of East Texas 177 form of thin small lenses or lumps, in color generally dark gray or brown. The country north of Manning is one of very low relief, but to the south and east the topography becomes gently rolling and a series of low hills is to be seen. On the sides and top of the low hill east of Manning a coarse- grained, medium hard, light gray sandstone is found in massive beds. This stone has a whitish granular cement which resembles some phases of the Catahoula. Some three miles south of Manning, along the tram and to east and west of it, there outcrops a sandstone of various degrees of induration, gray to brown in color, fine-grained, and for the most part massive, but in places thin-bedded. This sandstone contains numerous easts of fossils, for the most part lamellibranchs, but some gasteropods were found. This sandstone resembles in every way that found in the vicinity of Potomac on the Houston, East & West Texas Railway. The creek beds here expose soft sandstones and arenaceous clays of a prevailing light brown color and massive to thin- bedded. A section down a creek flowing south and emptying into the Neches some 3 miles above the place where the Manning train crosses the river exposes, along the banks, brown carbonaceous sands and clays, massive to thin and irregularly bedded, which continue to within 2 miles of the river. These materials un- doubtedly belong to the Jackson as exposed near Potomac. On the tops and edges of hills are sandstones of various degrees of induration, from soft to hard and quartzitic and usually con- taining casts of fossils. This sandstone varies from thin-bedded to massive, but it is for the most part fine-grained with a cement- ing material of a more or less porcelaneous nature. These sand- stones are for the most part of white to grayish-brown color, the brown shales being irregular and caused by iron stain. Locally, there is a prevalence of "pipe concretions" in this material. Lignitiferous sandy clays were to be found along the creek in some places. CADDEIiL SECTION The type locality of the Caddell clays is in the vicinity of the 178 University of Texas Bulletin town of that name in western San Augustine county near the Angelina river. It was at this place that Veatch found some of his Jackson fossils, including the specimen of Zeugledon. In the immediate vicinity the ordinary Jackson non-fossiliferous clays, weathering brownish and containing calcareous fossilifer- ous nodules, outcrop for an estimated thickness of 30 feet. The larger nodules are dark brown in color and are calcareous sand- stones in composition. These calcareous rocks in places form a thin continuous bed, and near the top of the bluff rising above the Angelina bottom a solid thickness of at least five feet was noted. Near the foot of the hill on which James Mott's house is built are dark chocolate clays, succeeded above by greenish, coarse sands and greenish clays weathering purplish. Ten feet higher in the section are clays with calcareous nodules. Bridge creek, which flows southward from White City, six miles east of Caddell, shows the following: In the first exposure on this creek is about 4 feet of Yegua, interbedded light greenish-gray, loose, medium grained sands and light chocolate, sandy clays containing sulphur. The clay is also in balls and small lenses in the sand. These beds continue until opposite "White City station, where basal Jackson clay with large calcareous nodules is found. Far- ther down the Jackson brown friable sand and sandstone come in with local hardenings, probably with calcareous cement. The hardest sandstone seen was almost quartzitic and light green in color. Farther down still are fossiliferous green clays, weather- ing brown, and resembling greensand. In these are fossils and a great amount of selenite. In places the Jackson contains limo- nitie concentric concretions 1 foot in diameter. Lower down on the creek the clay becomes unctuous, in color gray-drab, and breaks with a semi-concentric fracture. Separat- ing the clay layers are thin films of fine, light brownish gray sand, while towards the top of one 12 foot section is a light buff, finely-laminated, fine, clayey, brittle, but not well consolidated sandstone. In the continuation of this same section a hundred yards downstream the clay is chocolate-brown and sulphurous, with apparently a slight northward dip. The Jackson basal clays are found along Clear Creek for at The Geology of East Texas 179 least two miles. Very dark green grains, probably greensand, are irregularly distributed through the clays, some portions of which are entirely free from them, wHle others in immediate juxtaposition will have many. There is a great deal of sand in much of this clay, but still a large percentage of it is quite free from sand. In the creek just below the last section described are some fragments of a 3-ineh light gray sandstone layer containing casts like those noted on the old tram southeast of White City and on Shawnee Prairie. The thin sandstone comes from above the clay. Above the thin sandstone layer in the same section comes in a very light buff, compact clay. In less than one-fourth mile downstream we run into the Jackson sandy clay with green- sand, outcropping in the bed of the creek. Two thin sandstone dikes, of 1-inch and 2i/^ inches in width, were noted in the first deep cut in the brown clays. These cut the clays in a nearly perpendicular position almost at right angles to the bedding planes. Two other dikes were noted. Just east of the east line of the Lucas headright is a hard sand- stone, fine-grained, light gray, and well cemented, which is prob- ably a lo'oal lens, similar to exposure near Huntington and Burke and on Stovall creek. , The exposure at McGilbery Bluff on Bug creek near the east line of the John Lucas headright and 1 mile from the Angelina river at the edge of the Angelina bluff, carries a rich fauna of the Caddell, mainly of large Pinna and small gasteropods. A lens of grahamite measuring about 2 inches across was found in the dark purplish, ferruginous, fossiliferous sandstone. The section follows: 1. Chocolate clay 35 ft. 2. Greenish-brown, sticky clay with thin films of sand of green color", greensand, and ferruginous concretions, blackish or brownish on surface and dark purplish red inside, contain- ing an abundant fauna. Much of the clay resembles that of the basal Jackson near the head of Clear creek 7 ft. 3. Dark green sandy clay, very sulphurous. Sand layers often brownish-yelloiw. Contains much gypsum. Fossils found in the clay. Characterized by large rounded ellipsoidal clay ironstone concretions of a length of 3 feet and over. . 3 ft. All members contain abundant selenite. The concretions of 180 University of Texas Bulletin number 2 are in thin layers 3 to 6 inches thick and run in definite planes, but are not continuous. The chocolate clay (1) is of the same bed as is seen higher up on this creek. As usual, it is sul- phurous. It also contains ferruginous concretions, both of the concentric and flat-layered types. SANTA FE RAILROAD SECTION On the line of the Santa Fe railroad the Tegua- Jackson con- tact was not determined closely, but is probably between Mile Posts 100 and 101. There is 8 feet of thinly laminated clay, mainly dark chocolate- brown in color, but the more sandy layers grayish, with some thin limonite-stained layers. There is about 8 feet of light brown sand in cut just north of Mile Post 100. Between Mile Posts 99 and 100 the friable thin, shelly-bedded light brown sandstones resemble those on the Houston, East & "West Texas Eailway between Potomac and Hammock, in northern Polk county, and in the vicinity of Manning, southern Angelina county. Light, yellowish-green, sticky clay 2 feet thick and containing small masses of limonite is exposed one-fourth mile south of Mile Post 99. The top of the section at Mile Post 99 consists of 5 feet of thin-bedded, light brown, very friable sandstone stained with sulphur, underlain by about 15 feet of light brown, carbonaceous, laminated clay, weathering reddish-brown and interbedded with thin friable sandstones, some of which are cross-bedded. At the south end of the cut at Mile Post 97 a layer one foot thick of soft sandstone outcrops, made up of medium sized sub- angular quartz grains and carrying clastic flakes of selenite. The sandstone shows a very imperfect lamination, mainly brought out by thin films of iron oxide. It contains also small fragments of a black mineral, which is perhaps magnetite. This sandstone is lenticular, passing along its bedding into unconsolidated clayey sand. It is underlain by sandy, light bluish-gray clay, weathering on the surface to cream-color, forming semi-badlands, and about 6 feet thick. There is considerable cross-bedding, es- pecially in the more sandy portions. The sandy clays and clayey sands are thinly laminated. The section here much resembles TJie Geology of East Texas 181 that at Mile Post 100 on the Houston, East & West Texas Rail- way in northern Polk county, in structure, composition and materials. The two exposures belong to the Jackson and lie at nearly the same horizon. Close to the north end of the cut there is a marked concentric structure in the clayey sands. The core is a massive sand, 3-5 feet in diameter, and is surrounded by a concentric shell 1-2 feet thick, made up of alternate, irregular and wavy rings of sand layers stained with limbnite separated by layers not so stained. Three such core structures are seen. They may very likely have been formed since the deposition of the beds and may be of the nature of concretions. Th same general characteristics are seen in the several Jackson exposures south to half way between Mile Posts 96 and 97. One-half mile north of Mile Post 94 there is 5 feet of Jackson sulphurous, light chocolate-brown clay, underlain by 1% feet of light gray laminated sands. The clay is rather coarsely lam- inated and when unmixed with sand is plastic. Often, however, they are intermixed with sand and are stained with limonlte along the platy layers. The base of the section is about 10 feet below track level. The soil of the Jackson is dark brown, tinged with red, the color being characteristic of the foundation. This color is only a thin surface veneer seen in recent cuts. The Jackson topog- raphy is very gently rolling. The last Jackson clay is seen at Mile Post 94. It is thinly laminated and a light yellowish-green to greenish-gray in color with thin irregular and small plates of harder limonite-cemented clays. The maximum thickness of the exposure is 4 feet. It is overlain by the same thickness of Lafayette. The Jackson clay here is plastic and when damp has a bluish-drab color. SABINE RIVER SECTION Our knowledge of the Sajbine river section of the Jackson is limited to Veatch's sections, which are as follows^: About three-fourths of a mile below Robin's Ferry, at 30, there is an outcrop of 5 feet of blue fossiliferous clay on the Texas side of the river. It shows at this stage of the river two > Geol. Sur. La., 1902, pp. 131-2. 182 University of Texas Bulletin large concretions of hard white fossiliferous limestone. The out- crop yielded a rather extensive Jackson fauna, including Um- brella planulata and many large Gapulus americanus. At 31, a shelf of the same fossiliferous clay shows on the Louisiana side. The fossils here are not so well preserved. Dip S. 20 degrees E. Between this outcrop and' the outcrop of the Grand Gulf near Anthony's Ferry, ledges of Tertiary clays show at 32, 33, 34, and 35. At 34 a few fossils are exposed. Section , at 33 1. Dark gray and brown mottled sandy clay ("buckshot clay") .18ft. 2. White and yellow pebbly sand 5 ft. 3. Blue-clay, weathering brown 10 ft. 4. Irregularly bedded, laminated, slate colored clay and yellow sand 3 It. 5. Laminated chocolate-colored clay with occasional thin seams of yellow sand and small calcareous concretions 8 ft. The layers 3, 4, and 5, show a southward dip of 1:25. Near the northern en,d of the exposure is a small fault with a throw of about 6 feet. North of Anthony's Ferry, according to Veatch, these clays are succeeded by the Catahoula sandstone, giving the Jackson outcrop on the Sabine a width of between three and four miles. VOLCANICS Beds of volcanic ash in this area have been known and utilized commercially for many years. More recently the fuller's earth derived from the alteration of the ash has also come into use. The ash occurs in several ways. Principally it forms beds two feet or more in thickness, some of which are traceable for many miles and form excellent working horizons in the forma- tion. These beds are usually pure ash without admixture of other sediments and must, therefore, have been laid down very quickly or in very quiet waters. In some localities, as near Corrigan, the ash is mixed with diatomaceous material as though laid down in ponds or lakes, and at others it shows The Geology of East Texas 183 the dune like structure of deposits by aeolian agencies on land surfaces. The fuller's earth is met with also under various comiitions. Sometimes it occurs as a part of the same stratum as the ash, in which case the ash is usually found at the base and the fuller 's earth at the top, but this is occasionally reversed. Most frequently, however, the fuller's earth occurs in separate beds and in lenses and balls in the sands." Owing to the flayey nature of the fuller's earth its true character has not been recognized as fully as it should have been, and many occur- rences have been regarded as clay. Our more recent investi- gations indicate that these showers or floods of volcanic ash and tuff have furnished a much greater proportion of the ma- terials constituting the beds of our Coastal area than has ever been suspected. This is true not onlj' of the Jackson, but of the succeeding formations as well. CLOSE OF THE EOCENE In the uppermost beds of the Jackson we see the last forma- tion of strictly marine deposition which is now found exposed within the Texas Coastal Plain. The close of the Eocene, therefore, marks the final withdrawal of the sea from this area as the major medium of sedimentation and the substitution of flixvial and aeolian agencies and deposits upon low coastal lands and their continuations in deltas and lagoons. In this particular region the story of the emergence is not so well told as it is further south. Our investigations below the Eio Grande prove that the Gulf Coast Eocene extends south- ward in Mexico to the Conchos river, which flows along the northeastern face of the Tamaulipas range, reaching the Gulf east of San Fernando in Tamaulipas. The beds of the Tegua are characteristically exposed on the Conchos near Angeles as lignitie shales capped by yellow clays with shaly sandstones and clays with cannon-ball concretions. Down the river at Sonada there are blue and yellow gypsifer- ous clays interbedded with sandstones. The top of the Yegua is found in a hill one mile west of Mendez, where it is capped by the Fayette. Directly east of San Lorenzo creek, which 184 University of Texas Bulleiin flows into' the Conchos near Mendez, rises the Sierra de Pomer- anes, a range of high hills trending northwest and southeast. The western slope of these hills is composed of sandstone of Fayette and possibly of Jackson age and the top and eastern face is formed of the Frio clays overlain on the coastal margin by beds of marine Oligocene. The upper portion of the Frio in the Pomeranes hills, as well as in exposures on the river west of Tepetate, is made up of greenish clays and soft sands inter- stratified with heavy beds of gypsum. In the hills the deposits of gypsum include beds of alabaster and selenite, as well as massive gypsum. These extensive deposits of gypsum inter- bedded with the greenish clays and soft sands prove that the end of the Eocene was marked in this region by slow emergence and by dessication. That this emergence was pre-Oligo- cene is clearly shown by the relations of the beds of the two formations. Similar conditions are believed to have existed in eastern Texas and to have resulted in the deposition of a large part of the beds of salt and gypsum which are now found in such abundance in connection with the Coastal Domes of the region. CHAPTER VIII. INTRODUCTION Practically all of the deposits of post-Eocene age of the Coastal Plain of Texas, so far as their outcrops show, are non- marine. They consist of fluviatile and aeolian deposits and of sediments laid down in lagoons, estuaries or deltas, marked only by very scant remains of plants, land animals, fishes and brackish water invertebrates. The only vestiges of possible sea-shore conditions found are a few occurrences of a coquina in which the fragmentary shells are too comminuted to permit identification. In certain localities the conditions of sedimen- tation apparently remained the same .through successive epochs, so that there is no lithologic break to mark the parting, and in others the formations are connected by transitional beds. Such fossils as have been gathered from various localities in these beds show that they include deposits of Oligocene, Mio- cene, Pliocene and Pleistocene age, but in many places it is dif- ficult, if not impossible, to fix a line between the beds of. one of these series and those- of the others, or to separate the deposits into satisfactory groups, such as will serve as dis- tinctive in different areas- Until some basis can be found on which to make such division, it will be necessary to use group names, each of which will, where possible, include a mappable unit, and refer it to its nearest series. OLIGOCENE In Mississippi, the Jackson is followed by a series of lime- stones alternating with beds of sandy fossiliferous marl, which is called the Vicksburg. In the fossils of these beds, which are abundant and well preserved, we find very few of the forms occuring in the Claiborne or Jackson Eocene, and encounter many that are new. This formation is considered to be of Lower Oligocene age. Overlying the fossiliferous clays and limestones of the Vicksburg there is a series of sandstones and greenish clays 13-ET. 186 University of Texas Bulletin of different lithological aspect from any of the beds of the Mississippi Eocene. The only fossils found in them are re- mains of land plants and fresh water shells. These were first observed by Wailes at Grand Gulf, Mississippi, and were given that name. Owing to the confusion that has arisen in the use of this name through its application to beds of somewhat sim- ilar lithological character, which occur at other localities and have been found to be of different ages, and, in order to furnish a name not likely to be misunderstood, Veateh proposed the name "Catahoula" as a synonym for the "typical Grand Gulf" from Catahoula Parish in Louisiana where the beds are counterparts of those at the original locality. These are also considered to lielong to the Oligocene. Further eastward the Catahoula, or Upper Oligocene, is replaced by marine deposits and is represented by several sub- divisions which are based on fossil contents. Southward in Mexico the Lower Oligocene is present as beds of yellow sandy clays with quantities of the large foraminifer Orbitoides papyracea Bou. which is characteristic of the Vicks- burg. The upper Oligocene with similar yellow sandy clays includes heavy beds of nummulitic limestone and a consider- able fauna of eehinoderms, corals and other marine inverte- brates, proving its position in the Oligocene column. Deposition and Chaeacteb At the beginning of the Oligocene, that part of Bast Texas which was later covered by its deposits was a land surface, on the higher portions of which were exposed not only sands and clays, but probably very consideraltle bodies of volcanic ag- glomerates, tuffs and ash which had accumulated during Jack- son time. Along the coastal belt, occupying large basins or de- pressions, there were probably great deposits of salt and gyp- sum. So far as present surface conditions indicate this land condition continued through the entire period of Lower Oligo- cene, and not until its close did the lagunal and estuariiie waters take possession of this territory. Therefore, no trace of any marine deposits referable to the Vicksburg have been found in Bast Texas, nor is there any in- The Geology of East Texas 187 dication that the sandstones overlying the Jackson and referred to the Oligocene are, in any part, representative of Vicksburg time. Such deposits, however, may exist to the seaward and be overlapped by thfe later beds. "With the beginning of the Upper Oligocene, erosion seem- ingly became more .active, especially in the area occupied by the tufE and ash, and these furnished the principal part of the large quartz grains which make up the present rice sands and of the clays and fuller's earth which are interbedded with them. Apparently volcanic action had not entirely ceased, for there are beds of ash interbedded in the Corrigan which are original deposits and not derived from earlier ones. OORBIGAN In the Texas region Veatch applied the name Catahoula to the sands and clays which overlie his Jackson and underlie his Fleming. According to his map, the base of his Catahoula on the Houston, East & West Texas Railway is over four miles north of Corrigan. This would include the beds which fur- nished the Jackson fossils mentioned by Harris^ as coming from Kennedy's original locality, "a cutting on the Houston, Bast & West Texas Railroad 4 miles north of Corrigan, Polk County," earlier referred to the Claiborne, and whieJi now forms the base of our Manning beds. Veatch 's Catahoula, therefore, as mapped included the sandy formations lying be'- tween the Caddell clays and the Fleming clays, a part of which are Jackson and a part later. Matson^ calls attention to this and correlates the Jackson member (Manning sands) with the Fayette, with which it has really nothing in common, being a marine formation while the Fayette of East Texas is a fresh or brackish water deposit, underlying instead of overlying the Caddell clays. Veatch expressly limited the use of the term Catahoula to such beds as were of true Grand Gulf age and his name is therefoj-e retained for such beds as can be clearly referred to the Grand Gulf. Overlying the beds to which the name Cata- ^ Geol. Sur. La. 1902, p. 25. = U. S. G. S. Prof. Paper 98, p. 224. 188 University of Texas Bulletin houla can thus apply, we find a series of transitional beds con- necting the Catahoula and the Fleming, which cannot well be separated from it, and we will use Kennedy's older name of Corrigan for the entire group of non-marine deposits which lie between the Jackson and the Fleming and together consti^ tute our only mappable unit. They are supposedly, for the most part, of Upper Oligocene age. General Character and Relations The Corrigan comprises coarse "rice"^ sands and sand- stones with some clays at the base, overlain by finer sands and by yellowish green clay and claystones. The clays and claystones carry pyritic nodules and streaks of lignite and weather yellow to cream color. The sands are coarse to fine- grained and may be friable, cemented with opaline or por- cellaneous matter, or hardened to a dense gray-blue quartzite. There are local unconformities between the sands and clays and the sands often carry clay balls and are occasionally cross-bedded. Volcanic ash occurs abundantly, both unaltered and in altered forms as fuller 's earth and clays. The Corrigan is noted for the abundance of fossil palms, and the fossil wood which occurs in it is often opalized. Remains of animal life, are almost unknown. These are the beds to which Vaughan's name of Catahoula properly applies. In the exposures of the Trinity river region, while the basal beds or Catahoula are the same as those to the eastward, there appears to be at the top a transitional zone, in which sands of the Corrigan type are interbedded with calcareous clays similar to those of the overlying Fleming. On this account the limit is not as well defined as further east, and the upper line is drawn where the sands with porcelaneous cement cease and the clays weather entirely dark brown or black, instead of show- ing the characteristic yellow weathering of the Corrigan clays. These also carry plant remains and an occasional fragment of bone. ^ So called because of the resemblance of the grains to. those of rice. The Geology of East Texas 189 These upper beds maintain their character and thickness some distance west of the Trinity river. While they appear to be later than the Catahoula proper, they are definitely con- nected with it by the character of the sands and clays of which they are composed. For this portion of the Corrigan the name Onalaska has been proposed, from the name of a town in Polk county which is located on them. Excellent exposures may be found on Eocky and Kickapoo creeks east of Onalaska and on Harmon creek northeast of Huntsville. Stratigraphically, this group lies unconformably upon the Jackson; Lithologically, the base corresponds closely with the typical Grand Gulf, while the top is very similar to some of the Oakville beds of the Nueces section, but is older. It seems probable that the Corrigan represents some portion or all of the Oligoeene above the Vicksburg, and that while the base may be Grand Gulf, the upper portion is possibly Miocene. Area and Thickness As mapped, the Corrigan is broadest on the Sabine river, where its outcrop has a width of over twelve miles. It ex- tends westward as a belt of irregular width, narrowing to three miles in the northeast corner of Polk county. It widens again on the Trinity where the outcrop swings to the south- west. At the crossing of the Navasota river north of Nelleva Junction it is less than three miles in width and is but little more on the Brazos. Tht thickness of these beds is estimated at 450 feet. SABINE EIVEE SECTION The only details we have of the Corrigan on the Sabine are those given by Veateh^ : The Grand Gulf sandstones extend along the Sabine from Anthony's ferry to near Burr's ferry. The southeastward dip observed in the Coeksfield ferry beds and the Jackson continues to a point below Hattan's ferry with a tendency to show an ' Geol. Sur. of La. 1902, p. 133. 190 University of Texas Bulletin increased dip. Near Burr's ferry the dip becomes much less, being 1 :300. ^ A shelf of soft, fine, gray sandstone with a slight amount of calcareous matter is exposed on the Louisiana side a little more than one mile above Anthony's ferry. Half a mile below, a much larger shelf occurs near low water level. It extends well across the river, producing a decided acceleration of the current. The section is: 1. Yellow and trown silty sand to top of bank 8 ft. 2. White to grey sand with, faint traces of stratificatiion. Con- tains pebbles at base 10 ft. 3. Hard, flne-grained quartzitic sandstone 2 ft. 4. Greyish-blue, jointed sandy clay becoming lighter and more sandy above 15 ft. 5. Soft, white, fine-grained sandstone 8 ft. 6. Coarse-grained quartzitic sandstone 3 ft. 7. Grey to drab, jointed sandy clay 3 ft. Dip S. B. 1 :50. At Anthony's ferry a small flat-topped bluff on the Texas side shows no rock. On the Louisiana side, a little below, 4 feet of fine-grained Grand Gulf sandstone shows near water- level. Just above Snell's landing, a flat-topped bluff 35 feet high shows at its base 8 feet of .blue sandy clay. At Snell's landing high bluffs appear on the Texas side and extend for two miles down the river. Section at Snell's Landing: 1. Fine white sand with pebbles at base 25 ft. 2. Covered • • 12 ft. 3. Coarse, indurated white sand, capped with a layer of sand- stone about a foot thick 8 ft. Water level. Dip S. E. 1 :25. A mile below this exposure there is a good exposure : 1. Unexposed to top of bluff 40 ft. 2. Yellow sand, containing boulders of bufE colored, laminated, leaf-bearing clay 35 ft. 3. Coarse, white, cross-bedded, rather quartzitic sandstone. The Geology of East Texas 191 mottled with yellow " ft- 4. Greenish-yellow sandy clay 20 It. 5. Unexposed 10 ft. Water level. Bed 2 shows a phenomena almost Identical with that shown in the K. C. P. & G. R. R. cut near Shreveporc, where the beds are presumably of lower Eocene age. Five hundred yards be- low this section, this bed is much more f ally developed. Here the bed is covered with a regularly bedded, laminated, brown to slate-colored clay, three feet ihiek, with abundant plant impressions. This line of bluffs extends along the river half way to the mouth of Bayou Toro. The quartzitic sandstone increases in thickness, reaching a maximum of 10 feet near the lower end. This sandstone layer indicates that the line of bluffs are about on the line of strike and hence the dip is S. E. Near Hattan's ferry on the Louisiana side the following sec- tion is shown : 1. Drab, iron-stained clay, crumbling into small irregular pieces ("Buckshot clay") 17 ft. 2. Fine white sand with many small pebbles 3 ft. 3. Blue clay weathering yellow (Grand Gulf) 5 ft. A flat topped bluff on the west side of the river 2 miles below Hattan's ferry, shows a ledge of green jointed clay about five feet thick. The great southward dip, 1:25, exposes about 20 •feet of this bed. Sandstone ledges cause several shoals in the river below this outcrop but afford no good exposures. Four miles below, a ledge of fine-grained, porous sandstone shows a slight southward dip 1 :300. About half way between this and Burr's ferry, a range of high hills, rising over a hundred feet above the river, approach the river on the Texas side. One hill-point just reaches the river and exposes a ledge of sandstone near the water line. Foi-ty feet above water level a ledge of sandstone 25. feet thick outcrops in the hillside, in many places forming a protruding ledge and giv- ing rise to a number of small waterfalls where little streams from the hills flow over it. 192 University of Texas Bulletin About a mile above Burr's ferry, there is a small outcrop of soft white sandstone. This is covered with the usual pebble- bearing sands and pinnacled clays. SANTA FE EAILWAY SECTION On the line of the Santa Fe Railway in Jasper county, the base of the Corrigan is found just south of Brookland and it passes under the Fleming about 5 miles north of Jasper. Between Mile Post 94, where the last exposure of Jackson was noted, and Brookland the railroad runs in a flat swampy country showing only Lafayette sediments in one small cut. The Catahoula light green sandy clays outcrop in the long shallow cut which begins one fourth mile north of the 89th mile post, where there is a Ihin layer of porcellaneous sandstone over- lying them. There are thin lenticular layers of hardened clay within the looser clay and an irregular lens of sand overlies it. The sand is cross-ibedded and carries thin streaks of sulphur- yeUow clay. Southward, porcellaneous-cemented sandstone is encountered, but only as relatively thin layers interbedded with clay, and the first exposure north of the 86th mile post is of light drab, con- solidated clay. In the next cut to the south and beyond it the Catahoula greenish-drab clay contains calcareous nodules similar to those of the Fleming. Similar clay with similar concretions is found within the Catahoula outcrop on the road between Bevilport and Aldridge in western Jasper county. The north end of a cut south of Mile Post 86 is in Catahoula drab, or grayish-green, clay, and in the next cut just north of Mile Post 85 the unconformity between the Catahoula and La- fayette is well shoMii. At the base 7 feet of light gray, sandy Catahoula clay. Above lies 10 feet of cross-bedded Lafayette. The contact between the two is irregular, and small lenses and ridges of the Catahoula project up into the Lafayette, which is light brick-red in color. The last Catahoula outcrop is three-fourths of a mile north of the 79th mile post, where thin, irregularly-bedded, coarse, por- cellaneous sandstone at the base is overlain by 5 feet of yellow- University of Texas Bulletin No. 1869 Plate IX. CONTACT OF JACKSON AND CORRIGAN FORMATIONS. View on Trinity River near Trinity. TJie Geology of East Texas 193 ish-green clays with sulphur. On surface exposures these clays are bluish or grayish-green. The fossil plant Palmoxylon texense, which was described by Berry, was collected from the Corrigan at this locality.. In northern Jasper county, between the Angelina river and the line of the Gulf, Colorado & Santa Fe Railway, the area of the outcrop of the Catahoula forms the usual high sandy ridge of much dissected, mature topography, overlooking the lowlands of the Tegua and Jackson to the north and of the Fleming to the south. In this region the differential relief is 200 feet at a maximum and the surface is practically all reduced to slopes, forming hills and ridges dissected by deep valleys, which are narrow and steep in their upper courses. Recent rejuvenation, also noted farther westward on the Catahoula ridge, is very apparent at the headwaters of Beef creek, which lie in Sec- tions 146 and 151 of the land of the Houston Oil Company. The heads of the valleys have the broad, shallow and gently convex profiles characteristic of early to middle old-age erosion stages. Lower down the stream courses, the valleys abruptly break away into narrow, deep, box gorges, characterized by recent and still effective gully erosion. Some of the inner gorges are 50 feet, or more, deep. Above the recent trenches the gently sloping profiles of the old valleys are easily distinguished. The amount and thickness of Lafayette on the summits of some of the hills and ridges is surprisingly large. Locally, it is not less than 100 feet thick. It contains a large amount of ferruginous- cemented, coarse grit and conglomerate, more of which was noted here than anywhere else where the Lafayette has been examined. Mossy Hill, northeast of the old Truitt Place, near the head of Beef creek, is a ridge several hundred yards long, made up of ferruginous conglomerate at least 20 feet in thick- ness, and probably thicker. The hill-sides throughout the region of Catahoula outcrop are covered with fine gravel, which averages about one inch in diameter. The hydrated iron oxide locally cementing the pebbles into conglomerate was most likely deposited as bog-ore in springs and ponds. In many localities the upper slopes of the hillsides are thickly strewn with large fragments of silicified tree trunks. No- 194 Vnivei'sUy of Texas Bulletin where else has the writer^ noted silicified wood in as great abundance and in as large pieces as on the hillsides at the head of Beef creek. It is found in the Lafayette deposits and may have been indigenous to that formation, although that is by no means certain. Fragments two feet or more in diameter and ten or twelve feet long exhibit no signs of round- ing by rolling or water wear, but it must be remembered that all this silicified wood is very brittle and is easily broken with a sharp fracture along annual growth rings, .and at right angles to these rings. Large fragments in the beds of the present creeks, where they are subjected to attrition are nearly as angular and sharp on fractured edges as the silicified wood of the upper hillsides. The more resistant beds of sandstone or hardened clay in the Catahoula, when underlain and overlain by loose clays, often form terrace-like benches on the sides of hills. Numbers of small mounds were seen on the Barney Land and Robert Stone grants south and southeast of the wagon bridge over Beef creek and between Beef and Alligator creeks. Soft, greenish clays, partially indurated clays, mixed sands and clays are present in large amounts; sandstones, in all de- grees of consolidation from those easily broken with the fingers to hard quartzites; of all textures, from very fine to coarse grits; in structure, massive, thin-bedded or cross-bedded; and in color, from brownish or yellowish limonite-stained to white porcellaneous and silicified, are all found in the Cata- houla of this vicinity. ANGELINA KIVER SECTION Immediately below Bell's ferry on the Angelina river near its intersection with the Ayish bayou, the distinct shoals and rapids commence. The first outcropping noted was of a clay, blyish-green in color and usually somewhat arenaceous. This clay is .always yellow to yellowish-green on the outcrop. It forms shoals and also outcrops in the banks of the river to 15 feet above the water level. At the top of the clay a series of springs issue forth. ' Baker. The Geology of East Texas 195 Between the B. C. Lowe and the J. Conn surveys a series of bluffs begin which . determine the course of the river and cause the deflection noted on the map. The first bluff rises some 50 feet above the water and the strata dip some 3-4 degrees S. 50 "W. The section here is as follows: 1. Lafayette, clayey sand, lightly mottled for the most part. A film Immediately overlying the clay 1-3 inch in thickness is a contorted limonitic iron ore cementing the sand grains and gravel. This layer is probably caused by springs. Overlain by gravel which passes upward into mottled clayey sand 15 to 20 fti Unconformity: 2. Dark dirty green, gypsiferous clay, fractured with llmionite stains on fracture planes, which vary from yellowish brown to brick red in color. Selenite is in small fibres and Is common. Member becomes more indurated toward the top and here it passes into a sandstone much like No. 4 12 ft. 3. Ferruginous layer, botryoidal, mammillary 4 ft. 4. Sandstones, well indurated, light buff bo yellowish brown in color, depending on the percentage of iron. Occasion- ally shows psuedolamlnation caused by seams of limonlte. Medium-grained in texture. Matrix fine granular to por- cellaneous. Mainly massive, locally cross-bedded. Is in- durated sufficiently to form a perpendicular cliff and the top is a bench 6 ft. 5. Sandstone, cross.bedded, varying in Induration from me- dium-hard to loose sand, containing ferruginous concre- tidns, local layers having porcellaneous cement. Harder layers form benches between softer. Medium ,to coarse- grained. Color light brown when wet and light buff when dry. Stained by limonite 6. Yellowish green and greenish brown clay, compact and much fractured and where wet often dark copperas blue. Weath- ers dirty white 4 ft. TEXAS & NEW OEUIANS EAILROAD SECTION The outcrop of the Corrigan on the Texas & New Orleans Railroad does not exceed six miles in width, with Rockland nearly in its center. It has about the same width here as on the Houston, East & West Texas Railway. 196 University of Texas Bulletin It would appear that the outcrop of this formation is wider both to the east and west of these railway lines, where an upper member composed almost entirely of greenish clay is exposed on Rocky creek and on the Angelina river between Bell's and Bohler's ferries, which does not seem to be repre- sented in the sections along the railroads. The Jackson-Corrigan contact is south of Mile Post 107. In the first cut north of Mile Post 106 clays are interbedded with the porcellaneous sandstone. The section is: 1. Massive, medium indurated, porcellaneous cemented sand- stone ■ ■ 2 It, 2. Dark sulphur-yellow shaly clay, tasting of sulphur 4 ft. 3. Very shaly and "shelly" friable porcellaneous cemented sand- stone 1 ft. 4. Dark green sandy clay, irregularly stained dark-brown. Up- per 4-inches almost entirely dark-brown 2 ft. 5. Whitish, poorly indurated, porcellaneous cemented sandstone 6 ft. Dip 21/2° S. 10° E. Strike S. 80° SW. At the cut just south of Mile Post 106 the porcellaneous sandstone comes down to the track level and overlies the green clay. This sandstone is very shaly and thin-bedded. The top layer of the sandstone is more massive and typical. At the south side of the cut there were noted two small lenses of green clay interbedded with the porcellaneous sandstone. The maxi- mum thickness of the underlying compact, dark yellowish- green clay is 4% feet. The sandstone contains fragments of the underlying clay. The last bedrock exposed north of the Neehes river is at 106-B, where about 3 feet of green, compact, sticky Catahoula clay is associated with local indurations of light brown, fine- grained sandstone, small blocks of which are found on the sur- face. Light green, sticky, Catahoula clay, 7 feet in thickness, locally sandy, and with thin sandy layers, and small limonitic concretions and layers is found in the first cut north of the Angelina-Jasper county line. It is overlain by 18-inches of case-hardened, light gray, alluvial sandstone with pebbles. The bluffs at Rockland are capped by massive, light gray The Geology of East Texas 197 porcellaneous cemented sandstone breaking into large blocks. Under the Texas & New Orleans Railroad bridge over the Neehes is a rapids formed by a layer of light brown, hardened, sandy clay. Between these two rocks is greenish clay with local sandstones which sometimes, but not always, shov.^ porce- laneous cement. ' At Eockland, the section between the track and the oil load- ing rack is as follows: 1. Porcellaneous cemented sandstone capping the Hill 2. Light green clay, sticky, compact, fractured into very small blocks. More than 10 ft. 3. Compact, horizontal massive layer of coarse sandstone with large grains of quartz and metamorphic rocks, rounded to subangular, with a fine whitish granular matrix 4 ft. 4. Clayey sand, partially indurated, yellowish green, coarse... 8ft. The first cut south of the water tank at Rockland gives : 1. Porcelaneous cemented sandstone. 2. Clay, green, sandy, loose, weathering light gray 10 ft. 3. Compact sandstone layer, otherwise same as No. 4 . . . . 5-18 in. 4. Thin-bedded clayey sand, friable, light brown, locally limonite stained, with whitish granular matrix. Very poorly and irregularly laminated 3 ft. At the base of the next cut, porcellaneous cemented sand- stone lies on greenish Catahoula clays. The lower beds here are light greenish-gray sands and clays, very poorly consoli- dated, and Aveathering into semi-badland forms. There is a thickness of about 15 feet of these in the cut 1 1-8 mile south of Rockland. These clays are overlain by porcellaneous sand- stone in the first cut within the mile limit south of Rockland. The Catahoula formation is last seen at Mile Post 101, where the porcellaneous cemented sandstone is found. NECHES EIVER SECTION The Neehes river fiowing southeastwardly through the Cor- rigan furnished the following sections: To the west of the point where the Carter-Kelley Lumber Company tram crosses the Neehes and along the southern 198 University of Texas Bulletin bank, a series of high bluffs rise above the river. They expose at the top and well down the sides a medium to coarse-grained sandstone having a porcellaneous matrix. Underlying this is a white elaystone, somewhat arenaceous and of various degrees of induration. The sandstone is in places indurated to a quartzite and would make a good rock for concrete work. Approximately one-fourth mile down the Neehes from the point where the Manning tram crosses there is an outcrop of Corrigan sandstone in the bed of the river. This rock causes a shoaling of the Neehes at this point and rapids are produced. There is exposed here 15 feet of a medium to coarse grained, rather soft, sandstone with a distinctly porcellaneous matrix. The sandstone is much cross-bedded. Near the mouth of Shawnee creek, in southern Angelina county, two isolated hills of porcellaneous cross-bedded sand- stone are entirely surrounded by the bottom lands of the creek. The locality is within one-half mile of the confluence of the creek with the Neehes. One of the hills is about 50 feet high and covers some 4 or 5 acres, the other" being smaller. The sandstone is medium-grained, medium hard, locally quartzitic, and breaks with a splintery fracture. About one-fourth mile east of this there is a big bend in the Neehes, known locally as the Devil's Bend. A bluff rising some 35 feet exposes the following section: 1. Soft sandstone, fine to coarse-grained, and constaining plant fragments and clay balls. Porcellaneous matrix. . 8 It. 2. Yellowish green to greenish-brown clay, weathering yellow to cream colored, and, when indurated, breaking out in cuboidal blocks. Shows thin bedding on weathering. In an east-west direction these beds lie horizontally 15 ft. 3. Greenish brown to chocolate brown clay, weathering dirty brown, the upper 6-inches indurated to elaystone so that it stands out as a ledge. Structureless 4 ft. 4. Lignite, ignites with a match 8 ft 5. Thin-bedded, sandy clays and clayey sands, greenish- brown to bluish-green in color when fresh, but all weath- ering cream colored. Contain an abundance of sulphide of iron nodules, the origin of which is evident from the fact that some of the nodules are still in the form of stems • of plants, showing that the iron sulphide was precipitated from solution by organic matter partly derived from the The Geology of East Texas 199 overlying lignite seam. The occurence of the iron sulphide here explains the origin of the bluish green color that is seen everywhere in these clays at the water-level 5 ft. The dip on No. 5 in E-W direction was 2% degrees at one place. The rapids on the Neches 1% miles west of Aldridge have a fall of about 4 feet. They are caused by resistant porcellane- ous cemented layers of sandstone overlying a light brown, compact, fine-grained sandy claiy with plant fragments. The porcellaneous sandstone is in places finely conglomeratic with subangular fragments of quartz and chert. Large fragments of clay in this conglomerate, together with cross and irregular bedding, indicate channel conditions of deposition and local un- conformity. At Feces Ferry, some 2-3 miles up the river from Smith's Ferry, there outcrops in the bed of the river a bluish-green clay, somewhat arenaceous, slightly plastic, which weathers cream colored to yellow. This clay forms a shoal which ex- tends out half way across the river at low water. Overlying this clay is a collection of angular boulders up to 1% feet in diameter consisting of sandstone, fine to coarse grained, and varying, in hardness from soft to quartzite. This sandstone has a porcellaneous matrix, and could not have been transported far. Three hundred yards upstream from Smith's ferry there is another outcrop of Corrigan, which runs half the way across the bed of the river. The banks of the river in both these localities are made up of alluvium, but west of the river clays outcrop which lithologically resemble those of the Corrigan, and are succeeded on the higher land by typical Fleming calcareous clays. Near the top of hill overlooking Smith's ferry, the following section is exposed along the road: 1. Clay, weathering white and containing calcareous nodules. .15 ft. 2. Indurated, non-calcareous, arenaceous claystone 1 ft. 3. Green clay, weathering dirty yellowish green and containing calcareous nodules 10 ft The upper part of this section may be Fleming, as may also 200 University of Texas Bulletin be the lower member; but such material as the indurated layer has not yet been observed above the Corrigan. A good develop- ment of arenaceous claystones that belong to the Corrigan was observed in this vicinity and it may be that this section marks the transition between it and the Fleming, such as is found further west at Onalaska. Rapids on the Neches river, on the eastern boundary of the Ph. Baldwin grant, northeastern Tyler county, 12 miles east- northeast of Colmesneil, and one-half mile below Smith Ferry, are well exposed at a low-water stage. The rapids are formed of medium-hard Corrigan sandstone, carrying plant remains and a large amount of silicified wood. Structure and bedding is very poorly developed, but cross-bedding is present, striking N. 60 deg. E. and varying in dip from 9 to 27 deg. southeast, in a distance of 25 feet normal to the strike. Below the sand- stone is two feet of soft, blue-gray, sandy clay. The sandstone surfaces are perforated with long borings elliptical in cross sections with the peripheries of the ellipses flattened. These are made by a small, light green, fresh water crustacean. The Neches river at its low-water stage, is nowhere over 6-inches'in depth over the rapids. The rapids will probably explain the partially drowned con,- ditions on the Neches flood plain above them quite as well as Veatch 's postulate of the Angelina-Caldwell flexure. HOUSTON, EAST * WEST TEXAS EY. SECTION On the Houston, East & West Texas Railway the first ex- posure of the Corrigan sands is found at Bridge 95-Gr, where yellow and brown sandy shales are overlain by a mottled sandy clay carrying fragments of the shale. The relations of the two formations is better shown at Mile Post 94. Here the mottled red and brown sands, shales and clays of the Jackson: are overlain by a light yellowish brown sandstone with white markings. The contact shows that the Jackson was eroded prior to the deposition of the basal Corrigan sands and the sandstone contains large fragments of the underlying shale. There is also apparently a difference in dip. The Jackson seems to have an easterly dip, while sandstones dip south. The Geology of East Texas 201 Between this point and Corrigan, brown sandstones are found and the country is covered with a coarse gray sand. The quarzitic character of the sands is shown in the old quarry one-half mile north of Corrigan and one-quarter mile east of the Houston, East & West Texas Railway. At the western end the sandstone is medium to fine-grained, medium hard, white to gray and yellowish brown in color. It is for the most part massive, but exhibits some cross-bedding. Locally the sandstone contains hard rounded clay balls. In the eastern end of the quarry the hard sandstone grades into a thin-bedded, softer, rock. South of Corrigan a white sandy clay with a yellowish tinge is exposed 100 to 200 feet south of Bridge 93-D. In seams this clay has a drab color and small nodules of pure clay in it are brownish gray. Stains of limonite are common. The sand grains are white and being enclosed in a resinous gray to yel- lowish clay impart to the rock a spotted appearance with many of the white spots no larger than pinheads. The surfieial soil is creamy- white sand. The same material is exposed in the north end of the next cut south. In the center and south end of this cut is seen 3 feet of , light brownish-gray, thinly bedded, nodular clay, which weathers white. In the third cut south of Corrigan there is exposed a foot of broken, cream-colored sandstone of very fine texture with seams and geodie linings of milky-white opal. In this sand- stone are nodules of pale yellow clay and a few small flakes of selenite. The Corrigan in this locality is mainly composed of coarse to medium sized angular transparent quartz grains with a few well rounded fragments of black chert and dark erup- tive rock cemented together with a milky-white porcellaneous cement. Just M-est of the track an old quarry, opened to use the rock as ballast, gives an exposure of beds of this typical Corrigan sandstone one foot in thickness. The hill 20 feet or more high directly west of Mile Post 92 is littered over the surface with large blocks of sandstone. Underneath Bridge 92-C there is 3 feet of light greenish-yel- low, greasy, fine nodular clay fracturing with a smooth, unctu- ous surface, containing sulphur, and carrying large plates of 14-ET. ■202 University of Texas Bulletin selenite. Overlying this clay is fine cream colored volcanic sh, 7 feet in thickness, friable, and carrying thin seams and lenses of gypsum. This section has below it an outcrop of Corrigan sandstone, but the contact between the two is not visible. Rather fine conglomerate, bluish on the surface exposure and cream colored or light gray in the interior is found 300 yards south of Bridge 92-B. This conglomerate has pebbles as large as 1-8 inch in diameter of rounded quartz and angular pebbles of local sandstone ranging up to twice that size. This rock weathers cavernous and honey-combed like the topmost layer at Mile Post 100 and is a fair representative of the case-hardened layers which, locally, are quite common at the surface. A light bluish gray, very porous, coarse sandstone, 4 feet in thickness, with a calcareous ( ?) cement outcrops 100 feet east of the tract at Mile Post 91. Just south of Mile Post 91 the Lafayette with quartz, jasper and chert pebbles and sandy clay, exhibiting a faintly pronounced mottling into brownish- red and gray, overlies the Corrigan. At Mile Post 90 there are yellow and white sandy shales dipping 20° N. 70° W. Bear creek rises Sy^ miles southwest of Corrigan and flows northeastward to the Neches, crossing the Missouri, Kansas & Texas Railway just west of Corrigan. It is nowhere more than a mile and a half from the line of the Houston, East & West Texas Railway and gives some interesting sections which are inserted here for comparison with those along the railway which have just been given. At the crossing of the Missouri, Kansas & Texas Railway it shows about 12 feet of laminated thin and wavy bedded choco- late colored carbonaceous clays with partings of gray sand. On the outcrop these clays weather a dirty white. One mile, approximately, up the creek from railroad bridge there is a section of 8 feet exposed along the creek bank as follows : 1. Light brown clay lor fuller's earth. Thin hedded 4% ft. 2. White, ilne-grained, volcanic ash 3 in. 3. Greenish brown, structureless, gypsiferous clays weathering yellowish 3 % ft. The Geology of East Texas 203 No. 3 of above section resembles clay outcropping on Mis- souri, Kansas & Texas Railway between Corrigan and Benford. Approximately 1^/4 miles above the railroad bridge the fol- lowing section is exposed : 1. Gray, flne-grained volcanic ash. Irregularly bedded and fairly well Indurated. Ck)ntains yellow and yellowish, brown limonitic streaks. Forms the bop member of the ledge outcropping in creek and is only resistant member in section 1 % f'l^- 2. Brown fuller's earth (No. 1 of previous section) 3% ft. 3. Chocolate colored, carbonaceous, structureless, plastic clay.. 2tt. Immediately beyond, tbe following exceedingly interesting section is exposed : 1. White claystone, thin-bedded, sandy, shaly and seemingly non-calcareous, breaking very easily into angular and spheroidal blocks. Upstream grades into a massive soft sandstone 9 ft. 2. Fine-grained, soft, sandstone, yellow to buff in color and ex- tremely irregularly wavy and cross-bedded. Grades horizon- tally into a highly gypsiferous clayey sand colored brown- ish green, structureless, and containing a great abundance of small selenite flakes averaging 1-8 inch in diameter. Soft sandstone stands with vertical walls, but clayey sand takes an angle of repose of about 60 degrees. Locally the sandstone contains limonitic concretions up to 1% inches in diameter • 10 ft. 3. Drab to chocolate and dark brown slightly arenaceous shale, thin-bedded to laminated, containing minute cavernous spaces filled with a mineral hardness about 3. This material is brittle and breaks out in angular fragments where thin- bedded ; not caleite 3 % ft. 4. Yellowish brown, structureless clay, weathering yellow to cream colored • ■ 6 ft. .Overlying the section on top of the hill there is a sandstone with a distinct porcellaneous cement, medium to coarse-grained thin-bedded to massive. The dip on No. 3 member was 3 deg. S., measured north-south. A short distance further up the creek, the yellowish brown, highly gypsiferous member grades back into the cross-bedded,j soft sandstone and within the distance of 8 feet is seen to be 204 , University of Texas Bulletin overlain unconformably by No. 1 of above section, which here is 9 feet thick and massive, the material breaking out in spheroidal forms. Under road bridge 1% miles southwest of Corrigan and up- stream for a short way, there is exposed 8 feet of a fine-grained, white, soft sandstone with a white powdery cement. In the creek bed it is massive, then comes 3 feet of thin-bedded and laminated, and the upper 4 feet is massive. Approximately 2% miles southwest of Corrigan along the creek there is exposed the following section : 1. Buff to light drab sands, irregularly bedded 4 ft. 2. Clayey saud, dark blue and greenish, blue 1 ft. 3. Green to bluish green structureless clay with small patches of pyrite 2 ft. Upstream from here the greenish blue sand and clayey sand is found in sections up to 6 feet and locally it is much cross- bedded. Weathers cream to buff. In the last 50 feet of the section up the creek the surround- ing country becomes rather flat and the only material exposed is a gray colored sandstone, coarse to fine-grained, soft to quartzitic, thin and cross-bedded to massive, its most character- istic feature being the porcellaneous matrix in which the quartzitic grains rest. The smaller sand grains are usually angular to sub-angular and consist, for the most part, of clear quartz grains, but many angular to sub-angular grains of fiints and jasper are to be seen. The sand grains are by no means all small in size for locally angular to sub-angular peb- bles of quartzose, chalcedonic, and schistose nature are to be seen which are as much as 1^^ inches in diameter. Pebbles of black color, conchoidal fracture, and vitreous lustre, resem- bling obsidian, are somewhat common. Clay balls are very com- mon in the sandstone, and they are more common in the im- mediate vicinity of contact with underlying clay. This section is remarkable as being one of the very few of the east Texas Tertiary below the Lafayette to show conglom- erates of this character. One noticeable thing in the section up this creek was that no quartzitic and chalcedonic well rounded and sub-angular The Geology of East Texas 205 pebbles were to be noticed in tbe creek bed in its lower reaches. Continuing the railroad section, we find at Laurelia : 1. Doose, coarse, white quartzitic sand. 2. Bright red sandy clay 3 ft 3. Mottled red and brown clayey sand 30 ft. 4. Red and yellow sandy shales interbedded with coarse grained sand. Some cross-bedding and mottling in more massive portion 7 It. Unconformity : 5. Coarse-grained, bright orange and red sand with opaline pebbles and opalized wood 3 f t- Unoonformity: 6. Gray, yellow and brown clayey sands. The more clayey being laminated, the sandy, massive and mottled. Harder layers at top streaked yellow and white as at Mile Post 90 25 ft. The cut at 89-D shows at the base a bed of dark gray, mas- sive sands overlain uncomf ormably by mottled sandy clay. This has a very irregular surface and is overlain by a shaly con- glomerate carrying fragments of the mottled sandy clay. This in turn is overlain by a yellow clay carrying calcareous concretions. In no other section of the Corrigan with which we are familiar are there so many local unconformities as in the one under consideration. In the cut just south of 89-D is Corrigan sandstone, higher than the clays described in the preceding paragraph. There is about 6 feet of light gray, compact, fractured, sandy clays in the first cut north of Moscow, Mile Post 88. They weather cream-colored and are overlain by 2 feet of brown sandy clay with rounded pebbles, belonging to the surficial member. On the hillside between the town of Moscow and the railway station there is below, brownish-drab compact clay stained ir- regularly by limonite and weathering light gray on the surface. Locally, this is sand and not clay. Above, is clay weathering brown which swells up into a pimpled and cracked surface. The top of the hill at IMoseow, on the dividing ridge between 206 University of Texas Bulletin the Trinity and Neehes drainages, is capped with the porcel- laneous cemenled Oorrigan sandstone overlain by the uncon- solidated surficial mottled sand, clay and gravel member. The thickness of the Corrigan sandstone on top of the Moscow hill is 15 feet. Immediately under this, with probable unconform- able relationship, is a light grayish-green clay. The topography between Corrigan and Moscow is for the East Texas Coastal Plain and for a region near a drainage divide decidedly hilly. South of Laurelia the relief is not so- great as to the north. The higher elevations are capped by the relatively resistant Corrigan sandstone overlying non-re- sistant clays. On the Trinity road, one-fourth mile west of Moscow railway station, a hillside gives the following section : 1. Very calcareous, light green clay, imperfectly laminated, with nodules of hard, dense, very finely textured whitish limestone, some of which are as large as a foot in diameter. The surficial weathering of this clay makes the "black land." At least 6 ft._ 2. Fuller's earth, creamy white, laminated, non-plastic, becom- ing gritty towards the top 10 ft._ 3. Pine textured, laminated, cross-bedded light yellow clayey sand, weathering whitish to light blue, and with thin seams up to 1-4 inch in thickness of cream colored clay 3% ft.- 4. Light gray to light green drab clay weathering cream color on surface 3 ft. 5. Fuller's earlh like (2) 1/2 ft. 6. Clay like (4) . • 3 ft. Probably the most striking characteristic of all these section^ of the Corrigan between the Neehes and. the Trinity is the large proportion of tuffs, ash and fuller's earth which occur in them. A large portion of these were in all probability de- rived from the deposits of the Jackson volcanoes. These would include the rice sands, the obsidian of the Bear creek section and elsewhere, the many deposits of fuller's earth and similar materials, such as the swelling clays, and probably a portion of the unaltered ash, etc. But it also seems highly probable that a part of these beds of ash, tuff and the spheroidal weathering clays are original deposits coming from volcanoes active dur- ing Corrigan time. The Geology of East Texas 207 KICKAPOO CREEK SECTION Kickapoo creek rises north of Groveton and flows southward to CanarVj where it is joined by Rocky creek and then flows easterly, passing a mile or more south of Onalaska to its junction with the Trinity. About seven miles south of Groveton, Kickapoo creek emerges from a rather thick and broad bottom land into the open cut- over land of the Trinity County Lumber Company. Here, on the W. H. Raspberry headright, there outcrops on the bluffs overlooking the creek a fine-grained sandstone, fairly hard, cross- bedded to massive, white to gray in color. Its thickness ranges from two to three feet and it caps the bluff and is underlain by thin-bedded and cross-bedded sands. The sandstone in places contains clay balls and in one place an abundance of easts of fossil leaves was found. This is near the base of tht Corrigan, and two miles below this locality Kickapoo unites with its east branch heading near Wil- lard, and here the clays of the Corrigan outcrop. The first thing noted along this creek below the junction of its Bast Fork was the immense sand bars of almost pure white sand derived from the erosion of the Catahoula sands upstream. This sand is in all probability the source of the sands of the Trinity river noted at the Houston, East & West Texas Railway crossing over that river and elsewhere. This creek has many exposures of Catahoula sandstones and claystones along the banks and as shoals in the river bed. The sandy clays usually yhow up as yellowish on the weathered sur- face. It contains much iron as shown by the bluish green color in many places. Near the middle of the section the quartzose sandstone ap- peared containing rather large and angular grains of quartz, flint and jasper, aU set in a porcellaneous matrix. Rocky creek, near iis confluence with Kickapoo creek, flows through but little bottom land, and has high banks cut into the claystones and sandstones of the Catahoula. The members pre- sented in the section examined of up to 15 feet show for the most part a fine-grained, clayey, soft sandstone or arenaceous clay- stone of yellowish color on the weathered surface. It resembles 208 University of Texas Bulletin very much impure volcanic ash. One section just upstream from the road crossing below the store at Canary is as follows : 1. Irregularly thin-bedded to massive, yellowisli, soft, fine- grained sandstone containing at the base some fuller's earth up to 6" thick. More massive towards the top. Re- sembles very much an impure volcanic ash 8 ft 2. Fuller's earth, a fine grained or unctuous yellowish green clay having a semi-conchoidal or spheroidal fracture when dried out 2 ft. 3 In. 3. Light yellowish colored to grayish, fine-grained, soft sand- stone ■ ■..■• • ■ 8 in- 4. Puller's earth, same as N'o^. 2 2 ft. 5. Irregularly thin-bedded, or laminated and contorted, alter- nating laminae of a fine-grained, brownish green, clayey sand and a rather pure, unctuous, brownish-green clay resembling fuller's earth. The clayey sand, when in .the stream bottom is a bluish green (copperas) color due to the action of the water on the iron in the sand 5 ft. Dip here of 10° to the south, although in other places it is almost horizontal. Locally, the Corrigan has large, rather angular, calcareous nodules. By far the greater part of the fomation here, especially the upper portion, is made up of yellowish green clay. There is also non-plastic clay (fuller's earth) and some fine volcanic ash. The creeks in the vicinity of Colita and Canary exhibit long stretches of slack water held back by a resistant layer outcrop- ping farther downstream. Terraces along the streams are ap- parently due to the same cause. Below a rapids or waterfall, caused by the outcrop of a resistant layer, a gorge, sometimes 20 feet or more deep, is cut which comes to an end downstream at the next rapids or wafcorfall. The Catahoula in the middle reaches of these streams consists of cream-colored, light gray, light blue and mainly yellowish green sandy clay with locally semi-consolidated layers, and higher up the stream courses nearer the base of the formation with local lenses of opaline- cemented sandstone. Locally white calcareous concretions are found in the clays. Some of these are potato-like, or irregular in form, but most are long, generally branching pipes with i i University of Texas Bulletin No. 1869 Plate X. Pig. 1. CORRIGAN FORMATION. White Rock Creek, Polk County. Fig. 2. CORRIGAN FORMATION. Exposure of sandstones near Riverside. TJie Geology of East Texas ^ 209 irregular outside surfaces, sometimes very indistinctly ribbed. A cross-section generally shows them to be porous and some of them appear to have been built up of a growth in a concen- tric manner around a small central cavity. A number of these cavities may be found in the same "pipe." Below the mouth of Kocky creek there were exposures of sands, some of which were cemented with the porcellaneous matrix of the Catahoula, interbedded with greenish clays in which calcareous concretions were found in increasing num- ber until finally some two miles southeast of Onalaska these graded up into the green and brown clays of the Fleming that contain quantities L,f calcareous concretions and weather into black soil. Some of the concretions were long pipes with concen- tric cellular structure resembling slightly the structure of bone. These may be due to the replacement of rootlets. These transition beds between the Catahoula and the Flem- ing are the beds we have called the Onalaska. Going downstream below the Beaumont & Great Northern Railroad bridge the Fleming continued for about two miles. Here the stream makes a N. W. bend and again enters the Catahoula, some excellent exposures being noted. One notice^ able thing was the appearance of two very large, black petri- fied logs. On White Rock creek in Trinity county east of the Inter- national & Great Northern Railway the contact between the Jackson and Corrigau is found near the mouth of Caney creek. About one-fourth mile above the Beaumont & Great Northern Railroad bridge fossil leaves are found in a medium to coarse- grained, massive to cross-bedded, opaline cemented sandstone believed to form the lowermost Catahoula. Immediately be- low the sandstone there outcrops along the creek about 7 or 8 feet of laminated chocolate colored, sandy, shaly clays with some fine-grained sands. This lower member in all probability belongs to the Jackson beds and we have the contact here. The contact seems to follow along Caney creek in this vicinity for quite a distance, as the above section is repeated in another place one-half mile above where Caney flows into White Rock creek. At Chita postoffice, situated on the J. R. Parker Survey, 210 University of Texas Bulletin there is a high ridge trending through the country iu a south- west-northeast direction and it also probably marks the con- tact between the Catahoula and the Jackson. This ridge is covered with a very coarse sand made up of angular sand grains, some of which are as much as Vs to 1/4 inch in diameter. The grains are mostly pure quartz, but occasionally a fliat or jasper grain is noticed. Grains . resembling rose quartz oc- curred locally. 1E":NJTY KJVEE SECTION Between Riverside and the mouth of White Rock creek the Trinity river flows easterly, meandering along the strike of the Corrigan and gives a number of good sections of the lower Catahoula. Immediately downstream from the bridge at Riverside there outcrops, on the south bank and back from the river, a coarse- grained, cross-bedded, opaline cemented sandstone, for the most part rather soft. This same stone outcrops on the tops of the hills overlooking the river and some 40 to 50 feet above it. On the top of the hill there is an old quarry in this material. Here it is rather massive, but still rather soft. This stone has been used extensively by the International & Great Northern Railway in the building of culverts, approaches and abut- ments. It dresses well and seems to be admirably adapted for this use. About one-half mile downstream from the bridge the fol- lowing section is exposed on the south bank : 1. Alternations of sandstone and claystone in 2 It. layers.... 8 fit. 2. Claystone, -weathering whitish 3 tt. 3. Coarse-grained, gray colored, rather soft sandstone 4 ft. 4. Greenish-brown, sandy clay, weathering yellowish and cream colored. The clay contains many pyritic nodules and, where the water has acted on it, the characteristic "cop- peras" color is to be seen. Towards the top the clay he- comes indurated to a claystone. Structureless 40 ft. Approximately one-half mile below the mouth of McGee creek, on the south bank, there is exposed at the waters edge 8 to 10 feet of a gray to yellowish, structureless, fine-grained, TJie Geology of East Texas 211 fairly well indurated sandstone. This sandstone weathers out in cavernous forms. About one mile below the mouth of McGee creek, on the south bank, there is a bluff overlooking the river in which the following section is exposed: 1. Yellowisli sandy clays and clayey sands, for ttie most part structureless, but showing some cross-bedding. Contain some pyritic nodules 25 ft. 2. Highly cross-bedded, gray, coarse-grained, porcellaneously cemented sandstone, for the most part soft 20 ft. At Gibson's store, which is about one-half mile above the mouth of Carolina creek, there is a bluff on the Trinity county, side. It is hardly .any higher than the banks of the river, but at the base about 10 feet of gray sands are exposed. Immediately below the mouth of Carolina creek and along the eastern bank of the creek for quite a ways back from the river there is a bluff rising some 60 feet above the river. The section exposed here is as follows: 1. Greenish-brown clays, weathering yellowish, structureless . . 2 ft. 2. Structureless, Indurated, grayish brown, sandy layer 2 ft. 3. Clay and sandy clay, greenish-brown when fresh, but weather- ing yellowish, cream colored and yellowish brown. When near the water it takes on a blue color, due to change in the composition of the iron cement. Contains an abun- dance or iron sulphide nodules, which are crystalline in places and take on octahedral forms. The clay smells sirongly of sulphur and H^S. In the Carolina creek bed just above the mouth there are a number of springs highly charged with sulphur 10 ft. 4. Upper part consisting of a cross-bedded, fine-grained, gray to white. sandstone, medium-hard to soft. Bottom 15 feet cov- ered with sandstone blocks 45 ft. About 11/2 miles below old Carolina there outcrops near the water's edge on the south bank of the river about 6 feet of a medium to coarse-grained, hard gray sandstone, for the most part massive. The sand grains have an opaline cementing material. This rock varies from medium hard to the hardness of quartzite. In the creek there is a section exposed which shows excel- 212 University of Texas Bulletin lently the nature of some of the unconformities within the Catahoula. Here there has been a trough cut into the yel- low-weathering structureless sandy clays and in it 10 feet of coarse-grained, cross-bedded sands have been deposited. These sands are bedded so as to show the trough, and the cross- bedding appears as the minor structural feature. The sands vary locally from fine to coarse-grained, but some coarse angular quartz grains up to % inch in diameter were found and rounded clay balls up to one inch in diameter were also included. In color, the sands are, for the most part, gray and reddish brown, but in one place they were carbonaceous and of a brownish hue. A layer of 2 ft. of arenaceous claystone is also to be included near the base of the section. The sands are considerably iron stained locally. One-fourth to one-half mile above the Government Lock and Dam at White Rock Shoals there is a shoal extending across the river. The rock making up the shoal is a medium to fine- grained, partly indurated, massive, gray sandstone, stained reddish-brown locally and having many vertical joints. There is about five feet of this material overlain by five feet of gray sands containing some pyritic nodules. Prom, this point the river turns more nearly south across the strike of the beds. Chalk Bluff, on the Trinity river, is on the north bank about 200 yards downstream from the mouth of Mill creek. The sec- tion is as follows : 1. Cross-bedded, medium-coarse sandstone, some of it with opaline cement, other parts mixed with fine clay. Also contains coarse-grained quartz and rounded clay balls. Buff in color 25 ft. 2. Much fractured "mudstone" with curved fracture. Stained brown and red on fracture planes by iron oxide. 20 ft. 3. Greenish-yellow loose clay 70 ft. Between this exposure and the Beaumont & Great Northern Railroad over Mill creek the east bluffs of Mill creek are strewn with fragments of Catahoula sandstone of sizes up to 3 or 4 feet by 10 or 12 feet and of all degrees of induration from that so friable it can be broken to pieces in the hand to The Geology of East Texas 213 hard indurated quartzite. There is some fine conglomerate and palmetto leaves and opalized or ehalcedonized trunks are rather common. Three thin ledges of the sandstone, separated by clay, outcrop on these hillsides None of these appear to be over six feet in thickness. The upper one is friable and the lower one has thinned out at Chalk Bluff, where its place is taken by clay. The hillsides are covered with its debris for over a mile along the east side of Mill creek and much of this debris is workable stone. INTERNATIONAL & GREAT NORTHERN RT. SECTION There are good exposures of the Corrigan along the line of the International & Great Northern Railway. Two miles north of Riverside, the International & Great Northern Railway runs close to the outside of a meander curve in the Trinity river. The section follows : I 1. Shelly and thin-laminated, light, brown sands, in places in- durated to a friable rough-surfaced sandstone 10-12 ft. 2. Dark brown and brownish-black carbonaceous shale 3 ft. 3. Dark gray, compact, clayey, fine sand, fractured into small pieces and with a dull waxy appearance 7 ft. 4. Friable, rough-surfaced, much jointed, light-brown sand- stone with plants 4 ft. 5. Cream colored, very sandy, clay 2 ft. 6. Sandstone like (4) 1 ft. 7. Laminated sand, cross-bedded, medium-grained, light gray sands 10 ft All exposures on the Trinity river above this point belong to the Jackson, and the Jackson-Corrigan contact comes in No. 7 of this section. All beds above it belong to the Corrigan. One-fourth mile downstream from the above section is 25 feet of light brown and gray sand and sandstone, varying in degree of induration from friable to hard opaline-cemented^ locally quartzitic. Most of the sandstone shows an irregular lamination. The following sections are exposed as we go dovnistream : The first of these for the distance of a quarter of a mile or more exposes contorted bedded and thin-bedded light drab clay 214 University of Texas Bulletin about 10 feet in thickness. One-fourth mile downstream there is 15 feet of gray and greenish-gray sandstone of various de- grees of induration, from very friable to hard quartzite. Some of it is clayey and then it is fractured into small pieces and presents an irregular surface. The bedding is contorted. Plant impressions and leaves are plentiful. For three-fourths of a mile above the International & Great Northern Railway bridge yellowish-green clay and blue laminated sands are locally ex- posed in thin sections on the south bank of the river. The top of the hill at Riverside is capped with yellowish- green clay with calcareous nodules. This clay is about 20 feet in thickness. It is underlain ;by a ledge 10-15 feet of light gray, friable cross-bedded sandstone with large grains of pel- lucid quartz which we have called rice sand. These have their edges partly rounded and their surfaces clouded by abrasion. Underneath the sandstone is 10 feet of light brown hardened clay, much jointed. Just out of town is a -small gully with steep sides excavated in the' sandstone and underlying clay. Locally, the sandstone, has opaline cement. There is a southward dip of 2 degrees. Underneath the hardened clay is 15 feet of light yellowish-green, loose clay. In the sandstone at the top are pockets, lenses and small nodules of clay. The first exposure on railroad is 200 yards south of Mile Post 72, which whows 10 feet of poorly bedded, light yellowish-green, sandy clay. The dip is 3° S. "W. At the next exposure one-fourth mile south of Mile Post 72 the dip is 2° to the southward. The section is : 1. Hardened, light gray clay 4 ft. 2. Light yellowish-green clay earring a few calcareous concre- tions • • • • 13 ft. 3. Partly a'S a continuation of the same stratigraphic level as (4) and partly coming in above are thin non-oontinuous beds of friable light gray, coarse-grained, opaline-cemented, sub-angular, fragmented, quartzose sandstone, interbedded with loose, cross-bedded, coarse and medium-grained sands with small nodules of light yellowish-green clay 8 ft. 4. Loose, cross-bedded, friable, light gray, medium-grained, quartzose sand with biotite, selenite, and jasper as acces- sories 9 ft. The Geology of East Texas 215 Cream colored sandy clay 5 feet in thickness is exposed ia the cut at Mile Pose 63. One hundred yards south of Mile Post 75 is the following section : 1. Friable sandstone, fine-grained, opaline-cemented with plant impressions 4 ft. 2. Loose, fine-grained, light gray sand 2 ft. Stratigraphically above the last section in the cut at Mile Post 75 is the following section: 1. Opaline-cemented coarse and medium grained light brown and gray sandstone locally cross-bedded and stained with limonite. It is locally quartzitic and contains rounded nodules of clay and larger lumps of hardened clay more irregular in outline. Varies greatly in degree of induration 5 ft. 2. Light yellowish-green clay with calcareous nodules 5 ft. At Mile Post 76 is 6 feet of light gray, loose, poorly lami- nated sand. The Onalaska beds seem wanting in this section. The top of the Corrigan is seen on Harmon creek west of • the railroad. The first exposure, which is near the middle of the Catahoula section, is just aljove the abutments of the old bridge on the road from Riverside to Smither's farm. It consists of 10 feet of light green clay, much fractured. The second exposure is 250 yards upstream from the last and has 40 feet of light yellowish-green clay, the upper 5 feet partially indurated, overlain by 5 feet of opaline-cemented, cross-bedded, medium- grained sandstone with plant remains. The next exposure shows 25 feet of light yellowish-green clay. The heads of the tributary creeks and gullies have broad bare surfaces of light greenish or cream colored Catahoula clay. One mile upstream from the last mentioned exposure is the following : 1. Light gray hardened clay 2 ft. 6 in. 2. Unconsolidated, light yellowish-green clay 3 ft. 3. Hardened, light yellowish-green clay 1 ft. 4. Medium-grained, opaline-cemented, cross-bedded light gray sandstone 4 ft. 216 University of Texas Bulletin At the contact of the sandstone and clay are sulphur springs emitting sulphuretted hydrogen gas. The next exposure is one-fourth mile upstream: 1. Light gray, cross-bedded, opaline-cemented coarse-grained grit. The particles of the grit are, suhordinately, angular, dark colored chert, up to 1-4 inch in size, predominatingly angular, transparent quartz, with a minor amount of small rounded, light gray-drab clay balls, probably derived from the underlying clay. There is a very irregular, uncon- formable contact between (2) and (1) ; at one place a lense of medium-grained, light gray sandstone is found in the clay (2) and has an unconformable lower contact with the clay. This is at the top of the clay and is separated from the overlying sandstone by clay from 1 ft. to 6 ft. in thickness 10 ft 2., Very light gray clay, hardened and much jointed, rusty on joint planes 8 ft. Three-fourths mile upstream is 4 feet of light yellowish-green hardened clay. One-fourth mile farther upstream is at the base 8 feet of light yellowish green clay. On the hill above, with a covered vertical interval between it and the clay of about 10 feet is light gray, cross-grained, opaline-cemented sandstone 5 feet in thickness. Then after several exposures 0''' a few feel each of Lyb.t yellowish-green, unconsolidat;;.! clay, there comes one with 4 feet of yellowish-green hardened clay with irregular-surface, overlain by 3 feet of loose, light green clay. At an old cotton gin there are 6 feet of very friable sandstones, fine-grained, light gray, and much cross- bedded. The two exposures next upstream have 8 feet of light yellowish-green, unconsolidated, clay. The next exposure has 6 feet of light green, unconsolidated, laminated, fine-grained sand at the base, overlain by 3 feet of fine-grained, light gray sandstone, in which were found two palmetto leaves, as large as the modern palmetto, and resembling it. Another quarter mile upstream is the following section which belongs to the Onalaska beds : 1. Gray, medium grained sandstone, locally quartzitic 7 ft. 2. Coarse sand packed full of small white porous cylindrical calcareous concretions a It. 3. Yellow-green, fine sand 10 ft. The Geology of East Texas 217 Further upstream the exposures at the top of the Corrigan are blue .and gray clayey sand, locally indurated, with irregular surfaces and, locally, with a few small calcareous concretions. It forms rapids in the creek. The line between the Corrigan and Fleming is very poorly defined here. West of the Trinity there are good exposures of the lower Corrigan .along Nelson creek in the northern part of "Walker county. A traverse of Nelson creek from Moffitt Springs to the head, showed that it flows in the Corrigan. About one-eighth mile above the springs, a rock hill comes down to the creek. It is composed of medium to coarse-grained, massive gray sand- stone. An exposure of the same sandstone is to be seen about one-eighth mile above this point, where a rock shoal occurs in the creek. On the Wm. Roock League on the south side of the creek and about one-fourth mile back from it there is ex- posed, in a bluff overlooking the creek bottom, 8 to 10 feet of medium to coarse grained, massive, white sandstone containing pyritic nodules and having a fine granular matrix. The creek heads just south of the Bedias road. Exposures near the head give 5-6 feet of the yellow weathering, structureless, some- what sandy Catahoula clay. THE INTERNATIONAL & GREAT NORTHEEN SECTIONS IN GRIMES COUNTY The Jackson-Corrigan contact comes between the 22nd and 23rd mile posts. A sandstone quarry was formerly worked in the beds near the base of the Corrigan a short distance west of the track. Quartz sand as coarse as rice is reported from a locality 400 yards east of the Trinity & Brazos Valley Railway track a short distance south of Singleton and this is undoubt- edly derived from the Corrigan. One-third mile north of Mile Post 21 Corrigan light gray, irregularly indurated, sandstone 2 feet in thickness is overlain by much cross-bedded, opaline- cemented sandstone 6 feet in thickness. White and yellowish- green clays 3 feet in thickness are found 300 yards south of Mile Post 21. Roans Prairie has blackland soil underlain by light greenish- 15-ET. 218 University of Texas Bulletin yellow clay. At depths of from 20 to 30 feet good water is obtained in Corrigan sand or sandstone. There is a small hill of Corrigan sandstone 1 mile south of Eoans Prairie station; light greenish-yellow clay between Mile Post 17 and 16 ; 5 feet of cream-colored clay badland, clayey sand, locally indurated to sandstone, at Mile Post 16. At Mile Post 15 and two-thirds of a mile south there is 3 or 4 feet of cross-bedded friable sandstone, which belongs to the uppermost Corrigan. Three hundred yards south of Mile Post 14 is 2 feet of light gray claystone, the upper 1 foot indurated and fractured. Under- neath the last is 5 feet of lowermost Fleming dirty green sandy clay, very poorly laminated and with calcareous ce- mented nodules of sandstone. The Corrigan-Fleming contact occurs, therefore, near Mile Post 14. BRAZOS EIVER SECTIONS Our Brazos river sections include only the upper beds of the Corrigan and their contact with the overlying formation. As the bulk of the materials belong to the Neocene, the sections will be given later. Four hundred yards below the line between the E. Clampit and Wm. Kerr tracts, Corrigan quartzite outcrops in the river bank. The rock is 22 feet .above low water level. As here exposed the Corrigan is a medium hard, brownish- gray sandstone with lenses of hard brown quartzite. These quartzitic phases make up at least fifty per cent of the rock mass in this exposure. No estimate can be made regarding the thickness because of cover. The bedding is highly com- plex, ranging from thick and massive strata to thin-bedded phases with all degrees of cross-bedding and lenticular struc- ture. Two hundred yards south of this, along the river bank, an exposure shows 23 feet of sandstone. The lower 7 feet of this is present in last exposure, but the 16 foot interval above this shows no quartzite. Chapter IX NEOCENE INTRODUCTION The Miocene and Pliocene, which, taken together, form the Neocene, are represented to the east and west of us both by ma- rine and by non-marine deposits. Using the marine fossils as a basis, each of the two series has been divided into a lower, mid- dle and upper stage. The character of the vertebrate remains also permits a tripartite division of each series, but the exact equivalency of the Lower, Middle and Upper stages of each as shown by vertebrates and invertebrates has not been ascertained. All of the materials of Miocene and Pliocene age which occur at the surface in our Texas Coastal area are, as we have said, land or fresh water deposits, but weUs drilled to the seaward of these exposed bodies show that they do not continue indefinitely in that direction as land deposits, but that they are replaced by brackish water or marine beds. None of these, however, have given us a clear basis for a division of the beds. Even in the Galveston deep well, which affords us our best marine section, the beds, except those above 458 feet, which are clearly Pleistocene, and those below 2100 feet which carry a distinctly Miocene fauna, are of indeterminate age beyond the fact that they are Upper Tertiary or Lower Quarternary or both. At Saratoga and Batson about 70 miles a little east of north from Galveston the fossiliferous marine Miocene beds are found in wells at depths from 350 to 1200 feet. These are the only inland occur- rence of these beds now known and the presence of any of the post-Miocene beds of the Galveston well has not been recognized anywhere in East Texas. The conditions of the brackish water fauna is somewhat sim- ilar. At Burkeville a fauna was found which Dall' pronounced Upper Miocene or Lower Pliocene. The vertebrate remains found in same beds Matthew ascribed to the same age. Sixty- five miles south of Burkeville a deep well encountered the Burke- ville fauna at 3100 feet and continued in it to 4000 feet, but there 220 University of Texas Bulletin is nothing in the overlying beds to definitely fix their age. Nor do the vertebrate faunas east of the Navasota give us much better data for classification. The collections from the vicinity of Nava- sota and from Cold Springs, according to Matthew, are of Middle Miocene age. Those at Burkeville are of Upper Miocene or Lower Pliocene — ^none are distinctly Pliocene. Furthermore, east of the Trinity there does not seem to be any lithological basis for the division of the beds lying between the Oligocene and the Orange Sand, or Lafayette. Therefore, these clays with calcareous concretions and their interbedded sands, which together give us our only mappable unit, are grouped under the name Fleming and treated as undifferen- tiated Neocene covering the time from the Oligocene, or rather from the close of the Corrigan, into the Pliocene. The Neocene deposits in the East Texas Region, then, consist of only two mappable units: The Fleming beds and the La- fayette or Orange sand. The former comprises such deposits as occur between the Corrigan and Lafayette and covers parts of both the Miocene and Pliocene time. The Lafayette is Upper Pliocene in age. "West of the Brazos a better differentiation is possible and was made in the Nueces river section. In this region the Frio which is of Eocene age is overlaia in the neighborhood of Oakville by a body of brown sands lightly compacted and unfossiliferous. Overlying these are f ossilif erous sands which were grouped with the lower beds as the Oakville sands. The vertebrate fossils proved to be of Upper Miocene age. The brown sands may rep- resent the Middle Miocene or even earlier deposits. Overlying the Oakville we find the Lapara sands with vertebrate fossils of Lower Pliocene (Blanco) age and these are succeeded by the unfossiliferous Lagarto clays. The deposits west of the Brazos are much sandier than those east of that stream, the Lagarto clays being the only portion that corresponds lithologically with the main body of the Fleming. This would seem to imply that while east of the Brazos lagunal conditions prevailed from the beginning they did not extend westward until near the end of the period. The Geology of East Texas 221 PLElUnVG I General Statement The deposits which succeed the Corrigan in East Texas prob- ably have no exact counterparts in. other portions of the Gulf Coast. They consist of a broad belt of clays with calcareous concretions which are interbedded with sands. The texture and composition of the component strata indicate that they were deposited in the quiet waters of inland lakes, lagoons or bays beyond the imme- diate shcreliue of the sea and as terrestrial deposits on a compar- atively flat coastal plain. The sands show the remains of palms and palmetto. The invertebrate fauna is that of brackish water only while the bulk of the fossil remains are those of land ani- mals. These deposits are connected with the underljdng Corrigan by transition beds and are overlain uneonformably by the Lafayette or Upper Pliocene. The fossils found in them indicate that these deposits cover Middle and Upper Miocene and possible Lower Pliocene time. No forms indicative of the Middle Pliocene have yet been found, but may occur in or near the Woodville horizon. These deposits, — the Fleming in the east, and the Oakville- Lapara-Lagarto in the west, — are the coastal and terrestrial sedi- ments laid down contemporaneously with those of marine origin seen in the Galveston d#ep well and in deep wells in the Louisiana area which have yielded remains of Miocene and Pliocene marine invertebrates, no trace of which have, up to this time, been found* outcropping in this area. The Fleming clays were so named by Kennedy from the ex- posures near Fleming on the Missouri, Kansas & Texas Eailway east of Corrigan. His description follows: The deposits are best seen in the neighborhood of Fleming, where, a little west of the station, the Trinity and Sabine Rail- way line passes over a high hill made up entirely of them. The same clays also occur in a cut on the line of the Southern Pacifio Railway about a mile and a half north of Summit station, in Tyler county. 222 University of Texas Bulletin The clays are dark blue, pale blue, brown, red, yeUow, and pale green in color. They occur thinly laminated, or partially stratified and massive and have a strong tendency to joint or break into cuboidal blocks with a eonchoidal fracture. The most important bed of clay in this group is a blue clay, partially stratified, but showing a tendency to break up into blocks, and containing numerous concretions of carbonate of lime. This clay is perfectly smooth in texture and graduates into the underlying bed of red clay without any break except that of color, and the absence of the limy concretions which apparently do not occur in the red clay. At least where the beds were examined none were found. The red clay is in every other respect similar to the blue. Pale green, pale blue and brown clays are found overlying the blue limy clays at the different exposures, but occur most abun- dantly to the north of Summit station. These colors are not so persistent as the blue, and are probably due to some local cause. These clays in this portion of the State are overlain by and associated with a series of gray sands, which are mostly coarse graiued, sometimes massive ,and in localities cross-bedded an^ stratified. The typical exposure seen at Fleming shows them to be gray stratified sand containing fossil palm in great quantities, with numerous quartz, jasper and other pebbles, and to have at that locality a thickness of twenty feet These clays and sands occupy a belt from 15 to 25 miles in width and are followed by the deposits referred to the Lafayette. SABINE EIVER SECTION The occurrence of the Fleming on the Sabine is thus descrbed by Veatch, who suggests the name Burkeville beds for it : Outcrop near Burr's Ferry: — A small outcrop of the greenish- yellow clays of this stage occurs at the water 's edge a quarter of a mile from Burr's ferry Bluff at mouth of Boggy branch : — Bluff just below the mouth of Boggy branch shows the following section : 1. Stiff black soil 1 ft. 2. Fine white sand 37 ft. The Geology of East Texas 223 3. Light yellow, sticky clay, containing large irregular white calcareous concretions. Weathers into a stiff black clay..26f1!i 4. Covered to water level 17 ft. The blackland soil which caps this bluff is an erosion frag- ment of a much thicker bed which shows in the hiUs west of this exposure. This is a continuation of the blackland belt in which fossils occur at Burkrille. Near Columbia : — Shelf of clay exposed just below the ferry shows the following : 1. Yellow sandy loam mottled with gray 7 ft.. 2. Fine white and yellow sand containing gravel in the basal portion 13 ft^ 3. Light brown, slick-looking clay, streaked white. Contains small calcareous concretions 2 ft.. Water level. The flat-topped bluff on which New Columbia is situated con- tinues down the river half a mile Near its lower end a ledge of green calcareous clay, two feet thick, is exposed near water level. Outcrops below New Columbia: — The first exposure of Frio (Fleming) clays below New Colunlbia is at the log-slide at Knight's landing 1. Brown sandy silt, stained with red and yellow 7 ft. 2. Stratified white sand with gravel at base 17 ft. 3. Green sandy clay 10 ft. Two feet of green sandy clay is exposed at base of low pine- clad bluff on the Louisana side between Droddy's landing and Bearden's ferry. On the map, Plate XXXIV, he places the southern limit of the Fleming at Armstrong's bluff just south of the line be- tween Vernon and Calcasieu parishes, at which point it passes below the Lafayette. BUEKEVILiJE SECTION Baker describes the beds at Burkeville thus : The general facies of the beds at Burkeville resemble much 224 University of Texas Bulletin the Fleming of the type locality .and others farther west. Good exposures are most often found in recent gullies in old fields and prairies and these may or may not have a superficial black soil. The walls and promontories of a gully system have rounded outlines, for the material is fine and unconsolidated. In color the Fleming is most generally a light shade of grayish or yellowish-green, often weathering brown on the surface. The surface, when dry, is cracked like ordinary plastic clay. The material is fine clay and clayey sand with' small whitish limestone concretions. However, there are at Burkeville larger grayish-brown very fine grained limestone concretions with dendritic markings of manganese dioxide, concretions of large size and rough irregular outline of fine to medium- grained sandstone, and the fossiliferous breccia or beach lime- stone conglomerate known only from one-half mile east of Burkeville and south of Little Low creek, where fragmentary bones of land mammals and brackish water molluscs were found. In many places the, small white concretions are ar- ranged in thin beds parallel to the imperfect lines of strati- fication. The fine sands are also locally finely laminated and cross-bedded. Collections of fossils, both vertebrate and .invertebrate, were made at this locality. The invertebrates collected by us were sent to Dr. W. H. Dall, who studied them in connection with other collections from the same locality and others of similar age from Louisiana and Georgia. Matson^ gives the results of this study and lists 10 species from Burkeville. He states that the character of the fauna led Dr. Dall to refer it to the Pliocene. The list given by Matson" includes the following forms: Ostrea Virginia Gmel. Anomla sp. Potamides Matsoni Dall. Potamides Matsoni var gracillior Dall. Cerlthiopsis burkevillensis Dall. Pachychellus anagramatus Dall. Pachyclieilus satilensis Aldrich. 'U. S. G. S. Water-Supply Paper 335, p. 72. 'U. S. G. S. Water-Supply Paper 335, p. 73. University of Texas Bulletin No. 1S69 Plate XI. Pig. 1. CORRIGAN FORMATION. Quarry in Jasper County, exposing quartzites. Fig. 2. FLEMING FORMATION. Typical exposure near Smith's Ferry. The Geology of East Texas 225 Pachycheilus sauvls Dall. Paludestrina plana Aldrich. Neritina sparsalineata Dall. The mammalian remains were sent to Dr. W. D. Matthew. He reports as determinable: Tibia of a young rhinocerous, with the proportions of Teleoceras. Upper molar of a horse, either Proto-hippus or a long-crowned Merychippus. He states that both these specimens indicate late Miocene or possibly early Pliocene age, the horse tooth being pretty cer- tain evidence. It is therefore evident that in the vicinity of Burkeville the base of the Fleming is not earlier than late Miocene nor younger than early Pliocene. SANTA FE EAILVSTAY SECTION On the Santa Fe railroad the contact of Corrigan and Fleming was not seen, but judging from the topography it should be just north of Mile Post 76. From this point to Jasper the exposures show only Lafayette and even south of Jasper the Lafayette is more abundantly exposed in the cuts than is the Fleming. At Mile Post 73 light greenish-gray Fleming clay with calcareous nodules is exposed. This weath- ers on the surface to dark russet brown. Its maximum thickness is 10 feet. Bight feet of Fleming yellowish-green clay with calcareous nodules is to be seen in the first cut south of Mile Post 72, and at Mile Post 71. At the culvert between Mile Posts 71 and 70 the Fleming is greenish to yellowish-gray and weathers brownish. In the cut rimning north of Mile Post 70 is 8 feet of Fleming clay with calcareous nodules, weathering dark brown, but greenish-gray when \m- weathered. There is at least 15 feet of Fleming with calcareous nodules in the cut at Mile Post 70. The Fleming is well exposed on both sides of Bridge 69-C. At the south end of the exposure a thickness of 12 feet is seen and this exhibits a very imperfect arrangement of the ealcare- 226 University of Texas Bulletin ous nodules in layers, recalling similar conditions at Town Bluff on tlie Neehes in easternmost Tyler County. In the cut on the curve north of Mile Post 69 is 15 feet of light grayish-brown Fleming with calcareous nodules and some flattish concretions of sandstone like those found in the same formation at Burkeville. The Fleming outcrops at Bridge 68-B, at Green's Mill, and at Bridges 67-B and 66. The southernmost exposure of Fleming seen during this traverse consisted of bluish-gray clay situated 15 feet below the track level at Bridge 57-C. A section of Fleming clay, 100 feet in thickness, outcrops between the lowest Lafayette beds and low water level in Town Bluff on the Neehes between Jasper and WoodvUle. The lowest Fleming exposed, at the water's edge, 5 feet in thickness, is dirty green in color. Above is 10 feet of dark brown clay, the unweathered color being green or bluish gray, but seamed with brown limonite on joint and cleavage planes. In this layer were found fragmentary bones of fossil turtles and a well preserved mammal vertebra, which may be fossil, was found on the surface of this clay. Next above is 30 or 35 feet of light bluish and greenish clay. The upper 50 feet is mainly clayey sand, cross-bedded and laminated, in color dirty green or dark brown. There are calcareous nodules throughout the section and in its middle portion these are imperfectly arranged in more or less wavy and not always parallel layers which give to the beds the appearance of a rude stratification. The top of the Fleming forms a terrace like bench, interrupting the steep profile of the bluff. This bench has been formed by numerous springs which issue from the top of the impervious Fleming and have undermined and washed away the overljdiig Lafa- yette. TEXAS & NEW OEIiEANS EAILROAD SECTION On the Texas & New Orleans Railroad the first exposure of Fleming is at Bridge 101-E, where 18 to 20 feet of yellowish- green clay with a few calcareous nodules is seen. In the first cut above the 100th mile post 7 feet of dark green clay is found and outcrops southward to Bridge 99-D. At 99-C there is at The Geology of East Texas 227 the base 1 foot of friable fine clayey sandstone, slightly case- hardened, overlain by 4 feet of loose "shelly" clay. Then there comes in under the Lafayette a light gray sand and clay locally case-hardened and having a strongi taste of alum. From 99-B the Lafayette forms the sole surface exposure. Thin wavy laminated medium grained sand layers alter- nating with light brown or light cream clay with whitish cal- careous nodules to a thickness of 8 feet overlain by faintly mottled clayey sand mainly yelowish brown in color with small spots of darker red 2 to 3 feet in thickness covered with "black-land" soil to depth of from 6 inches to a foot, are found in a cut on the Moscow, Camden and San Augustine Railway, one-fourth mile northeast of Moscow. The beds here dip almost due east at an angle of 7°. HOUSTON, EAST & WEST TEXAS RAILWAY SEOTION On the Houston, East & West Texas Eailway the Corrigan- Fleming contact occurs near Moscow. The first exposure of the Fleming, is under Bridge 89-B 1% miles north of the town. Blue-gray case-hardened sandy clay 2 feet in thickness underlies 3 feet of light mottled surficial member of a light yellow color with a faint mottling of slightly darker yellow or red ill the second cut south of Mile Post 86. One mile north of Seven Oaks 2 feet of case-hardened gray, coarse sandstone is unconformably overlain by the Lafayette. Occasionally the sandstone contains a small bunch of clay or the clay forms the lining of tubes. One mile north of Leggett and 4 feet below the track level is 1 foot of soft gray clay with blotches of black oxide of man- ganese along joint faces. Dark gray, sandy, sticky clay with small white calcareous concretions is found 4 feet below the track level at the north end of second cut south of sign post 1 mile north of Leg- gett. In these clays were seen several masses (6 or 8 inches long and 1 or 2 inches wide) or compact, hard, light yellow, very fine grained limestone with dendritic markings of black oxide of manganese along cracks. These clays are 3 feet thick. The surficial sandy and clayey member, mottled in its 228 University of Texas Bulletin upper 5 feet, has maximum thickness of 10 feet, but the lower 5 feet in the center of the cut is sticky gray sandy clay be- longing to the Flemiag. In the north end of the cut just south of Bridge 81-B and below the track level is exposed 12 feet of medium grained loose sand with just clay enough in it to enable it to stand up in typical badlands forms of buttresses built up of small spires. The surfleial layer, not sharply demarked from the underlying, is mottled grayish and red. In the light gray sand close to the section's base was noted local concretion-Uke hardenings of the sand, colored black, probably with wad or some other form of black oxide of manganese. The last three cuts are in the side of the hill north of Leggett station. The highest point in Polk County is a hill rising 95 feet above its base and situated 2 miles south-southeast of Leggett. The top of this hill is covered with the Lafayette member, with its usual characteristics. Not far below the summit of the hill are 4 springs of good water. The porous sandy Lafayette is underlain by the calcareous Fleming clay and the water stored in the surficial member seeps out when it strikes the top of the underlying impervious clay. A well drilled for oil 2 miles west of Leggett penetrated 10 feet of lignite at 1000 feet below the surface — probably Ja.ckson. A well three quarters of a mile northeast of the high hill gives water containing sulphur, lime and salt. It penetrated dark cream colored clay with limestone concretions to a depth of 47 feet. So at a minimum there is 125 feet of the gray clay with calcareous nodules in this vicinity. The colors of these clays probably are largely dependent on the amount of hydroscopic and interstitial water which they contain. In the first cut south of 79-E' is found, the clay with calcare- ous nodules weathering to a dirty green on the surface. The blue gray clays with calcareous nodules outcrop in the south part of the town of Leggett and underlie a "black-land" prairie one-half mile south of the town. Clay with calcareous nodules outcrops 20 feet below Trestle 73-A for a thickness of 5 feet, succeeded by 3 feet of mottled surficial member. The Geology of East Texas 229 There are 6 to 8 feet of the gray clays with calcareous nodules exposed in a cut at Mile Post 72, where some beds are quite sandy and consolidated enough to form thin flaggy fri- able sandstone. These Fleming, clays extend at least as far south as Livings- ton, giving the outcrop a width of 28 miles on this railroad. The contact of the Oorrigan and Fleming near Onalaska has already been noted. Southwest of Onalaska the Fleming out- crops half way between Pointblank and Patrick's Ferry over the Trinity. It shows up here as greenish clays with calcare- ous concretions, weathering out into blackland. This Fleming runs up to within a mile or so of Pointblank. The Fleming was also found outcropping in a gully about one mile east of Canary postofftce. TRINITY MVEE SECTION At Eed Bluff on the Trinity River on the James Eankin Survey Fleming greenish-gray clay with calcareous nodules and cross-bedded sands contains a few bone fragments. The beds have a maximum thickness of 15 feet. In the middle of the exposure is a one foot layer of oolitic shore-line limestone conglomerate, containing a very few jasper and quartz peb- bles of small size and an occasional bone fragment. At Pine Island on the N. Amory Survey, in the Trinity bot- toms, a portion of the bluff land is now included within the bottom which entirely surrounds it, being bordered by Duck Creek on the south and the river on the north. The northeast corner forms a low bluff on the river at the base of which is 6 feet of dirty green sandy clay with calcareous nodules. Just east of Camilla there is a considerable body of gray medium-grained friable sandstone in the Fleming. Similar beds are found a short distance below at Johnson's Bluff, where they also include fresh-water moUusks. These deposits extend along the river to a point south of Drews •Landing, near Smithfield. Here an outcrop of Fleming, 10 feet in thickness, shows friable fine-grained gray sandstone in lenticles at the base, with 5 feet of greenish-gray, russet- brown, mottled clay with small, white calcareous nodules over- 230 University of Texas BuUetin lying it. Fragments of bone were found in this. The Flem- ing is here overlain by the Port Hudson, with the usual layer of Lafayette-derived pebbles at the base. A mile below Drews Landing, is a section showing 5 feet of light-gray Fleming clay with calcareous nodules. COLD SPRINGS SECTION. Coldsprings, west of the river, is in the midst of an impor- tant outcrop of the Fleming. In this region the Fleming brown and gray clay has a considerable portion of brown, buff, and white sand. In places there are large boulders of grayish brown, soft sandstone, some of which are 10 to 12 feet in length. There is also a fine-grained, hard, brown claystone and numerous calcareous nodules. Crystals of selenite are found loeaUy. Pure white sand, with only a minor amount of clay, is also found. Fossils of mammals were found in the region extending from 2 miles north to 2 miles west of Cold- springs. The bones, with the exception of a mastodon's skull (TrUophodon) , are fragmentary and are scattered through the clays. Planorbis was also found at this locality. Two miles west of Coldsprings on the Coldsprings-Dodge road there is quite a development of Fleming gullies or "bad- lands." The exposures here show 25-30 feet of Fleming drab to pearly gray colored clay mottled with brown towards the top and on the surface all brown, but the soil is always black and waxy. These clays contain layers up to 2 feet thick of cross-bedded gray to white, fine grained, medium hard, opaline cemented sandstone. The clay also contains an abundance of calcareous nodules. These "badlands" extend from the above point northeast- erly until they reach a point about 1^/4 miles north of Cold- springs. These exposures were searched diligently for 'fossils and quite a few vertebrate remains were found. Among other things might be noted the jaw bone of a mastodon {Tetrabele- don), equus teefth, camel, numerous rodents, alligator (?), tur- tle, etc. etc. The fossils were collected under the locality num- bers of Nos. 344 and 345. The Geology of East Texas 231 At Evergreen postoffice small lenticular masses of gray fine- grained sandstone are found in blue and green clays carrying calcareous nodules. Three hundred yards from the south line of the Euth Miller Survey, at Evergreen, brown lignitized wood and bones were found in a well at a depth of 70 feet. Blue clay was penetrated for practically the entire depth. Collections of vertebrates secured from the Coldsprings horizon, which is above the center of the series of deposits in the Trinity drainage here referred to the Fleming, were sent to Dr. W. D. Matthew, who reports as follows: 344. Two miles west of Coldsprings. "Trilopkodon sp., parts of lower jaws and separate molars, mostly well preserved. The best specimen shows a large part of the lower jaw with mi-| and the molars of the opp'osite side. Part of the symphysis is pre- served, and apparently a little of the alveolus for the lower tusk. Symphysis is moderately long, slender; not decurved. The species is a very small and primitive one in most respects, but the retarding of the posterior teeth so that m- does not come into use until m' is worn out and dropped is suggestive of Upper Miocene species, such as T. euphypodon. The small size and primitive construction of the teeth are more suggestive of Middle Miocene. Indicated age, probably Middle Mi'ocene. "Pecary, gen. indet., jaw fragment, m'. This, might be anything from Perchoerus (Oligocene) to ProstJien- nops (Upper Miocene). It is small and primitive, so far as the tooth gioes, but this is not conclusive, as the progressive characters of this phylum are in the front teeth. I can not identify it with certainty as belonging to any known genus or species. Indicated age, Oligocene to Upper Miocene. "MerycMppv.s sp., upper and lower teeth. A lather small and moderately progressive species; it might be Upper or Late Middle Miocene. " lAlticameliis, distal ends tibia and metapodial. Indicated age. Middle Miocene to Lower Pliocene. 232 University of Texas Bulletin "Crocodile and Tortoise fragments. 345. Pointblank road, north of Coldsprings. "Cervid," ef. Dromomeryx, horn fragment, calcanemn. "Camelid, gen. indet., jaw fragments, proximal phalanx. "Rhinoceros, ef. Aphelops, several fragments limb bones, calcaneum. "Large Ehinoeeros, ef. Teleoceras or large Aphelops, frag- ments of limb bones. "Proboscidean, ef. TrilopJiodon, unciform. Indicated age of the above specimens, Middle Miocene to Lower Pliocene. 345. One and one-fourth miles north of Coldsprings. "Eystricops sp., upper jaw with m^; lower molar. This is more primitive than the one known species of this genus, which is Upper Miocene and Pliocene. It is intermediate between it and the supposed ancestral type, the Steneofiier group of the Upper Oligocene and Dower Miocene. Indicated age, probably Middle Miocene. "Blastomeryx sp., last lower molar. This is apparently distinct from any known species, decidedly niore progressive than those of the Lower Miocene, less soi than the Upper Miocene species B. wellsi, more perhaps than the Middle Miocene species B. gemmifer. Indicated age, late Middle Miocene or Upper Miocene, "Oreodont, gen. indet., upper canine and premolar. Indicated age, Miocene or Lower Pliocene. ' ' Carnivore, indet., scapholunar and head of metatarsal. "Proboscidean, ef. Trilophodon, fragments of teeth. Indicated age, middle Miocene to Pliocene. ' ' Trionychid fragments. "Garpike scales. ' ' ?Snake vertebra. "Merychippus sp., cf. seversus, upper and lower teeth and fragmentary foot bones; part of right lower jaw, Piffij. The Geology of East Texas 233 This is a Middle Miocene stage, although small and primitive Mery- chippi do survive into the Upper Miocene and Lower Pliocene. No trace of any of the distinctively Upper Miocene horses among these fragments. Indicated age, Middle Miocene. 351. Two miles north of Coldsprings. "Cervid (IDromomeryx) radius. Indicated age, DroTnomeryx is Middle Miocene to Lower Pliocene, but this evidence is very slight. 352. Red Bluff, Trinity River. "Protohippine horse, lower tooth. Indicated age. Middle Miocene to Pliocene; nothing more definite. "The Coldspring material lacks any of the characteristic Upper Miocene Lower Pliocene Equidae, it has two or three spe- cies that appear to be in a Middle Miocene stage of evolution, and it has nothing recognizable as of the distinctively Upper Mio- cene types. The best specimen is the little Mastodon (Tril- opliodon) which is the smallest and most primitive species I have seen, except for a few very fragmentary specimens out of the Middle Miocene of Colorado (which have been called proavMs • and may represent the same species). ■ "I do not see. anything to modify my former correlation of the fauna' with the Middle iliocene (IMascall, Deep River and Pawnee Creek beds) : it is rather confirmed by the Triloj^ho- don. But, as I wrote before, the survival of the Middle Mo- eene fauna of the Central Plains to a somewhat later age in Southern Texas would not be unexpected." Bluish-gray and dirty green Fleming clay outcrops at the town of Oakhurst. There are only two exposures of Fleming on the Trinity Valley Southern Railroad between Oakhurst and Dodge, where most of surface is gravel-covered. INTERNATIONAL & GREAT NORTHERN RT. SECTION On the International & Great Northern the Fleming clay has its base about 10 miles north of Phelps. On the Huntsville branch 16-ET. 234 University of Texas Bulletin between the 5th and 6th mile posts west of Phelps is a dirty green clay, cracked into small fragments which harden when dry. One- fourth mile west of the 6th mile post is 10 feet of dirty green clay, weathering light cream and with many calcareous nodules. At the base is a few inches of thin flaky, fine-grained sandstone, light gray in color, containing calcareous nodules. The uppermost Fleming on the International & Great North- ern is found between one and two miles north of Willis, Mont- gomery County. It is generally dirty greenish-gray clay, weath- ering brown. It also has small calcareous nodules and local lenses of poorly indurated sandstone. The lower exposure of Fleming on Harmon creek west of I. & Gr. N. Ry. in Walker County is about two miles below the junc- tion of the east and west forks. It consists of bluish green sticky clays which weather brown and have calcareous nodules. In the lower Fleming on this creek are local lenses of opaline-cemented coarse-grained sandstone. Near the mouth of the east fork and a short distance above it this sandstone is interbedded with the dirty green sticky clay. One mile above the forks is light gray nodular hardened clay, 7 feet in thickness and forming a rapids on the east branch one-fourth mile farther upstream. The base of the section is 5 feet of greenish-gray medium and coarse- grained sand with calcareous nodules locally poorly indurated and with an irregular surface. Above this is 5 feet of greenish gray consolidated and structureless clay. At the top is 5 feet of dirty green sticky clay with white calcareous nodules. The' top clay weathers russet-brown. For three-quarters of a mile above this point semi-indurated sandstone forms a series of shoals and backwaters. The rock forming the shoals is full of potholes. Above the shoals the valley narrows and becomes gully-like. One-half mile above where the gorge begins gray, thin, opaline cemented, medium-grained sandstone layers dip southward at an angle of about 15°. Between these sandstone layers are thin beds of a vitreous-lustred fine ball clay, the original color of which appear to have been light greenish-gray, although it is now al- tered to a yellowish-brown. This clay is non-plastic. The south- ward dip lessens within 10 feet and is probably one of deposition and not one of deformation. Then the beds dip steeply in the op- posite direction at an angle of about 10°. A good section is seen The Geology of East Texas 235 where the Phelps road crosses near the head of the creek. Here is about 10 feet of partially laminated greenish-gray clay with a very few calcareous nodules. A local lens 5 feet thick, of cross- bedded medium-grained, subangular quartz sand is found in the clay. The clay is sandy towards the top. The surficial soil is mottled gray and brick red. The west fork of Harmon creek, also called Penitentiary branch, heads at Huntsville, where there are good exposures of Fleming clays. Near the State Farm and on the Midway road li^ mUes north- west of Huntsville, the Fleming consists of light green structure- less clay with white calcareous nodules, local indurations of light gray sandstone, and local indurations of light yellowish-green clay with or without calcareous nodules. The clay weathers to russet-brown. The sandstone locally has opaline cement. About one-half mile north is the folowing section: 1. Black land soil with calcareous nodules 1-2 ft. 2. Puller's Earth containing very little grit, hut a large number of calcareous nodules. Varies In color from cream at the . base to light dirty green at top 15 ft. 3. Light brownish-drab or cream-colored plastic clay 8 ft. This section is near the base of the Fleming, although what is probably Fleming is found on this same Midway road about 3y2 miles northwest of Huntsville. GRIMES COUNTY SECTION On the MadisonviUe branch of the International & Great Northern Railway the lowermost Fleming is exposed in the cut at Mile Post 14 (14 miles northeast of Navasota) where there is 5 feet of green sandy clay, very poorly laminated and with cal- careous cemented nodules of sandstone. All of the nodules were small save one, which was very irregular in shape, resembling the top roots of a tree and 4 feet in length. At the south end of the cut is the characteristic russet-brovra weathered soil of the Fleming. One-third mile south 2 feet of light gray friable sandstone at a lower level than the Fleming mentioned above may be upper- 236 University of Texas Bulletin most Corrigan. Two-thirds of a mile north of Anderson there is a total thickness of 4 feet of gray friable sandstone in the Flem- ing. These are merely locally indurated blocks. Two hundred yards north of the Anderson station there is more of this sand- stone, but here the concretions are more rounded and possess ne appearance of bedding. The elevation of Ajiderson Court House is 368 feet, according to the United States Geological Survey. From Anderson to Navasota the railroad passes over Fleming, mainly clays, but locally with gray brown sands and sandstone. Seven miles northeast of Navasota and one-half mile east of Becker, on this railroad, flat topped mesas, capped by sandstone and very arenaceous limestone begin and continue nearly all the way to Navasota. These are entirely to the south and east of the track and rise about 100 feet above the track level. The Fleming in this vicinity consists of the following materials: (1) sands of all texture from the finest up to coarse grit or fine conglom- erate, (2) brown and dirty green clays with calcareous nodules; (3) very arenaceous thin and irregularly bedded concretionary limestone; (4) clay ball conglomerate in a coarse sand matrix. These materials are either channel or littoral deposits. Mammal- ian bones are found in a layer of coarse grit or fine conglomerate. They are fragmentary, sometimes water worn, and are associated with rolled Cretaceous fossils. Petrified wood, differing from that of the older formations in being less consolidated, lighter in weight and duller in lustre, is found with the bones and shells. Fresh water TJnios are found in abundance in the clays between the 3rd and 4th mile posts of the Madisonville branch in shallow gullies just to the east of the right of way. The bones are found in the deeper gullies to the east of the second mile post. South of Navasota the Fleming continues to 1% miles beyond Crooks, where the Lafayette begins, the tippermost Fleming be- ing made up of dirty green claj's with white calcareous nodules. "West of this it continues southward and is exposed at the Hous- ton & Texas Central Eailroad crossing of Clear creek, just east of Hempstead, where it has the appearance of the Lagarto of the Niieces section and, like it, carries manganese as fragments of wad. Of the fossils collected from this vicinity, Dr. Matthew makes the following statement: The Geology of East Texas 237 349. Two and one-fourth miles north of Navasota. "Meryckippus, small species, of. M. seversus, but probably not identical, upper molar and fragments of foot bones. "Rhinoceros, cf. Aphelops, fragments of teeth, head of radius. Indicated age, Miocene. ' ' Camelid, , cf . Protolabis or Procamelus, fragment lower mo- lar,, astragalus, navicular, unciform, fragments of foot bones, ? symphysis of jaw. Indicated age, Miocene or Pliocene. "Testudo, large species, carapace fragments. "Crocodilian, fragments of skull. Indicated age. Middle Miocene, but Upper Miocene or Lower Plio- cene is not excluded. "General conclusions: Fauna ot Navasota and Cold Springs locali- ties appears to be the same. It is certainly not earlier than Middle Miocene of Osborn's correlation, nor younger than Lower Pliocene. Absence of all characteristically Upper Miocene or Lower Pliocene mammals points to Middle Miocene as the proper correlation. But there are two points which should be considered as making for a pos- sible later date than the comparison indicates: (1) Our land faunas are mostly derived from the north and northwest, and older types may have lingered longer along the Atlantic and Gulf coasts than in the northwest, thus making the fauna seem older than it is; (2) Knowlton regards the Mascall on plant evidence as Upper Miocene. This, if accepted, would set our whole scale of continental Neocene horizons a little higher than does Osborn's correlation. If you give much weight to these considerations, they might serve to set the correlation up to Upper Miocene. The fauna is quite decidedly older than the Blanco." So far as reported, no vertebrate fossils have been found in the Fleming which are referable to the Blanco or other later Pliocene horizon. The horizon from which the Navasota fossils were taken and that of the Burkeville fossils are similarly related to the Cor- rigan-Fleming contact and are near the present surficial base of the Fleming beds. The Coldsprings horizon is much higher and is in the upper half of the Fleming. It would, therefore, appear that the base and evBn the middle of the Fleming west of the Neches is older than the base of the Fleming east of that stream. 238 University of Texas Bulletin BEAZOS EIVBR SECTION- On the Brazos river we seem to have the meeting point of the eastern and western phases of the Neocene, and in Hidalgo bluff we find overlying the Corrigan, beds which seem clearly referable to the Fleming, and others that are characteristically Oakville. OAKVUiliE General Statement The deposits at the type locality on the Nueces river are those of rapid currents, of shallow water, grits and coarse sand, cross- bedded, with some beds of clay, but oftener with balls, nodules or lenses of clay imbedded in the grit. Some of the sand forms, a sand-rock which is apparently firm and hard, but much of it is so feebly coherent as to fall apart on a slight blow of the hammer. Local beds of conglomerate occur. Only a few fossils have so far been found in these beds, but such are determinable— Pro if oMppMs medius, Cope; P. perditus,. Leidy; P. placidus, Leidy; ApJielops meridianus, Leidy, etc. — are sufficient to determine its age as Loup Fork. In their eastern extension the base of the Oakville is marked by its conglomerate of rolled Cretaceous fossils, oysters, gryphaea and other bivalves, sometimes unbroken but often ground almost to sand. BRAZOS RIVER SECTION On the Brazos the Oakville, or basal divsion, consists mostly of soft sandstones and sands which are coarse, gritty, angular grained. These are sometimes laminated and regularly bedded, at others fine-grained and eross-bedded, somewhat lenticular, and often badly contorted, slightly calcareous, yellow to gray colored. In places they carry small white clay pockets and pockets of yel- low to grayish ■ white clay. Streaks or lentils of gravel occur throughout the beds. The gravel is usually small, not more than an inch in diameter at any place, but is usually much finer. It may be made up of quartz and chert pebbles, or of rolled Creta- ceous shells. The lenticular beds are very irregular in structure and texture, showing the sorting of water action. At one end these- The Geology of East Texas 239 beds may be fine sand, -whicli is gradually replaced by fine gravel towards tbe other, or both ends may be sand, while gravel occu- pies the center of the lens. These lenses are frequently partly laminated, but the laminae are not regular, being often wedge shaped and of different texture, the coarser and finer material intergrading with each other. Towards the base the beds appear, so far as seen, to be more regular in their texture, hard, close grained and quartzitic in places and interbedded with a bluish colored clay. The quartzitic phase of these lower beds is not uniform but usually interrupted, fine sands often occupying large spaces between the quartzitc portions. These beds present the appearance of having been deposited in rather shallow, turbulent waters, such as might occur along an open coast line subject to violent storms or active tidal work. Or, they may have been deposited in stream channels where the waters have been intermittently rapid and slow. They appear to be mostly of fresh water origin. Kelley 's section of Hidalgo bluff is as follows : Oakville: 1. Interbedded sandstone and clay, with loose sands. The sand- stone ranges from very fine grained to coarse. Is massive in one place and laminated in another. There is no regu- larity in ithe beds along their horizontal extension and falls have obscured the vertical section in places. This rock is characterized by the following points: It is light gray to yellow in color, generally coarse, beds 2" to 6" thick, well indurated when exposed to the air. It forms the caprock of ithe bluff ■ • 29 ft. 2. Dirty yellow or grayish clay, very massive. Weathering to badland forms. No nodules were found in this member, but the clay is highly charged with lime 16 ft. 3. Loose sand, medium-grained, with several lenses of sand- stone exposed in a small area. These lenses have a parallel arrangement, the long axis extending east and west. Rolled Cretaceous fossils were noted and one bone fragment col- lected on the surface 11 ft. 4. Clay with lime nodules. Color dirty yellow to gray. Local lenses of reddish-yellow sand. The clay is otherwise massive 17 ft. 5. Coarse, loose sand capped with 6 Inches of indurated sand- stone. Rolled Cretaceous fossils and fragments of silicified 240 University of Texas Bulletin wood are present, but no vertebrate remains were noted. The base of the sand carries enough pebbles to constitute a conglomerate ^ ^''• 6. CroBs-bedded sandstone ranging from a conglomerate with pebbles of sandstone and clay to fine sand. Color gray to yellow • • ■ ■ 26 ft. 7. A cociuina sand formed of small fragments of shell, little or no cement or fine sand. Would make good road material for surface. Color white to gray. Rolled Cretaceous fossils noted 5 ft. Fleming: 8. Pine grained sandy clay, colored buff or dirty yellow. The material stands in vertical faces along gullies 20 ft. 9. Massive light bluish gray clay with streaks and nodules of lime. The interval is so covered by slumping that it is impossible to give a detailed section. The base is less limy than the upper part 54 ft. Corrigan:' 10. Massive clay, slightly sandy with root casts, color dirty gray ito yellow. "Will not effervesce with hydrochloric acid. Very similar in all other lespects to the overlying Fleming . • 15ft. 11. Sand cemented with a clayey material. The color is a dirty yellow or buff. Casts of roots and balls of clay were noted. The lower two feet of this section is honeycombed with worm holes. This same zone is noted under K-24 at Hidalgo Falls 10 ft. 12. A very complexly bedded sandstone \^■ith no^ quartzite. Color same as above. Grain medium to coarse. A bed of clay 6-inches thick divides 12 and 13 16 ft. 13. Corrigan sandstone containing lenses of quartzite. Massive to thin-bedded with marked cross-bedding. The color is gray to reddish-brown. Grain medium to coarse 22 ft. There is a marked difference in the exposure at the south and north ends of the bluff. Beds were found in the north end which are identical with beds found just north of Erwin, Grimes County, but the^se do not outcrop in the south end of the bluff. East of Hidalgo bluff about half a mile another bluff shows ' The Corrigan is considered to be limited by the lime test in sep- arating it from the overlying Fleming. The Geology of East Texas 241 the Corrigan-Fleming contact with what is probably a repre- sentative of the Oakville overlying it. The entire section as exposed here is as follows : Oakville : 1 At top the bluff face shows about 80 feet of interbedded clay and sand with some beds of sandstone, the entire section being highly calcareous. Bone fragments may be found in the sands, but so far have not been taken from the clay or sandstone ..•■..•■ 80 ft. 2. Coarse loose sand, conglomeritic at the base. The sand is capped with 6-inches of well indurated sandstone. The sand shows marked cross.bedding. Rolled Cretaceous fos- sils were noted, but no bone fragments were present.... 5ft. 3. Goquina sand composed of comminuted shell fragments, rolled Cretaceous fossils are present in plenty and a few bone fragments were noted. The rock falls to pieces under the hammer, and the weathered parts can be crushed in the hand. Color dirty white 5 ft. 4. Interbedded clay and sand. The sand is fine-grained, locally indurated and stands in vertical faces due perhaps to some clay being present 15 ft Contact — Conformable ? Fleming: 5. Massive clay, blue-gray in color, carrying many calcareous nodules! No fossils were noted in this interval 50 ft. Corrigan: 6. Sandy clay, or sandstone, cemented with clay. This rock fractures under the hammer into small cuboidal forms showing the effect of the clay content. One zone shows many worm-borings, with oblate cross-section. Color is yellow to greenish yellow 15 ft. 7. Thin flaggy sandstone, highly cross-bedded and lenticular in places. The color is dirty white. No opalized wood and very few fragments or pebbles of clay 16 ft. 8. Interbedded quartzite and sandstone, grayish brown in color. 4 ft. Beginning at the top of No. 3 there is a marked change in the nature of the sediments present. Sand and sandstone be- come more plentiful as we go up in the series, the Cretaceous 242 University of Texas Bulletin fossils are more plentiful and better preserved, and bone frag- ments are increasingly abundant. On the Brazos river near Old Washington a section shows : 1. Altered brown sandy loam 5 ft. 2. Bluish-gray sand showing lines of stratification in places 1 to 2 ft. 3. Indurated gray sand with pockets of white clay 4 ft. 4. Clay % to 1 ft. 5. Coarse gray sand 1 tt- 6. Sandy clay 1 1'- 7. Fine bluish gray sand 4 ft. 8. White clay in pockets 2 to 6 in. 9. Gray sand and sandstone 3 ft. 10. Clay 6 in. 11. Coarse angular sand with vertebrate fossils 10 ft. 12. Gray sandy clay 1 % ft. 13. Sandstone with streaks of clay to water 3 ft. In digging a well at Old Washington a piece of a jaw and teeth were found in the sand No. 11 of this section. This is Oakville. It was from similar beds in this vicinity that the collection of vertebrate fossils was made on which Shumard based his statement of the discovery of an extensive Miocene formation in Texas^ : "The Texan strata consist of calcareous and siliceous sand- stone, and white, pinkish and grayish siliceous and calcareous marls. The calcareous beds are often almost wholly composed of finely comminuted and water worn shells, chiefly derived from the destruction of Cretaceous strata, and in places abound in fossil bones and plants, usually in a fine state of preserva- tion. The bones have been usually found in excavations for wells at depths ranging from 20 to 60 feet below the surface, and consist of genera closely allied to, or identical with, Tit- anotherium, Rhinoceros, E'quus and Crocodiles." The Fleming beds occurring in these Brazos river exposures belong to the basal horizons as found at Coldsprings and Navasota and these, as has been shown, are probably of Mid- dle Miocene .age. Succeeding them we have, in place of the 'Trans. Academy Sciences, St. Louis, Vol. 2, p. 140, 1868. The Geology of East Texas 243 Burkeville beds with brackish water fauna, such as occur in the Sabine section, the Oakville beds of Southwest Texas with a vertebrate fauna of Loup Fork age. The stratigraphie equivalence of the Oakville and Burkeville is, therefore, indi- cated, although the two groups of deposits may not, as a whole, cover an identical time interval LAPARA General Statement The close resemblance, both in texture and structure, of tha Oakville and Lapara formations makes it exceedingly difSeult at times to say which is Oakville and which Lapara. The Oakville deposits have been described as those of rapid cur- rents of shallow water, chiefly grits, coarse sand, cross-bedded, with some beds of clay, but oftener with balls, nodules or lenses of clay interbedded in the grit. Some of the sands form a sand-rock. Local beds of conglomerate occur. The description of the Lapara corresponds to this very closely. This has been described as sands and clays interbedded and cross-bedded. The sands are coarse and sharp, often forming grits and including pebbles of clay and calcareous concre- tions. The clays are jointed and parti-colored, light red, green, etc., and in some localities appear as a conglomerate of clay pebbles. Fragments of bone are common in them, but they are so worn as to prevent recognition^. Nowhere throughout the whole area under consideration are these Lap- ara sands in a mappable condition. While it may be said they are present at many localities, they occur only in very small areal patches or within the limits of a vertical section in which they are often overlaid by sands and gravels of a later age, or are overlain by the clays of the succeeding Lagarto. Throughout the eastern portion a number of Unios are found, together with a number of pieces of bone, but these bones are usually in such comminuted fragments that no iden- tification is possible. The presence of Unios would appear to indicate that a portion of these beds at least were of fresh ' Dumble, Journal of Geology, September-October, 1894, p. 560. 244 University of Texas Bulletin water origin. Fragments of bone are common in the beds on the Nueces but they are often so worn as to prevent recogni- tion. The fossils collected there were submitted to Prof. Cope, who pronounced the horizon to be Blanco, and states that nothing from either locality indicates a horizon as low as Loup Fork. liAGABTO General Statement The Lagarto beds of the Nueces were described as a series of sands and clays of a different character from the Lapara, and overlying them. These beds comprise light colored clays — lilac, lavender, sea-green, greenish-brown, and mottlings of these colors, jointed and showing many slips. In places the upper portion contains a considerable amount of sand, gravel, and lime, and the change in a single stratum from one kind of rock to another takes place within a very few feet. Where the limestone or calcareous sandstone caps the clays, strings of limestones extend downwards into them for a distance of Six or eight feet. The clays contain quantities of semi-crystal- line pebbles with manganese dendritions, and indeed, man- ganese appears to be one of the characteristics of the clay wherever found. The upper portion of the beds is usually a sandstone. No fossils have been found in them^. Although somewhat' changeable in some localities, the gen- eral description of the Brazos Lagarto may be given as heavy deposits of clay. These clays are brown, weathering snuff colored," yellow, blue and sometimes gray. The general struc- ture appears to be massive, but when dry they break into small blocks. They are all highly calcareous, in places show- ing nodules of lime, particularly in the darker colored bands. In the yellow, the lime is completely disseminated throughout the whole mass. . At irregular intervals, particularly in the yellow colored clays, we find thin seams of a fine-grained more or less laminated sandstone. These seams are rarely more than eight inches to a foot thick, and in places not very con- tinuous. These sandstone bands lie usually from ten to twenty ' Dumble, Journal of Geology, September-October, 1894, p. 560. The Geology of East Texas 245 feet apart, but are somewhat closer at the base of the clays These sandstones also partake of the calcareous nature of the clay in which they are enclosed. There appears to have been a considerable time interval in this region between the deposition of the uppermost Lapara beds and the succeeding Lagarto. These two are totally dis- similar to each other. The Lagarto is essentially a clay deposi- tion, evidently laid down in much deeper water carrying a great amount of lime. The waters from these beds are usually slightly saline in their nature. On the other hand, the Lapara is essentially a sand, which, with its vertebrate remains and Unip and fresh water shells must have been laid down under fresh or brackish water conditions, and is evidently a coastal or lagunal beach formation. The Lapara appears to have been considerably eroded before the deposition of the overlying Lagarto and the Lagarto itself appears to have been highly eroded before the deposition of the overlying gravels and sands. In some localities these Lagarto clays appear undulat- ing or wavy, but whether this is due to erosion and rounding of the remaining portions of the surface has not as yet been satisfactorily explained. These clays appear as a wide belt extending from the Brazos river westward to and beyond the Colorado river. They go much farther east than the Brazos, as they tie up with the blue calcareous clays seen south of Navasota and in the vicinity of Howth. They also appear on the eastern side of this river in the neighborhood of Hempstead. A section on the Brenham- Hempstead road between Hempstead and the river shows : Lafayette: Lagarto : 1. Dark soil 1 ft. 2. Yellowish-brown sand with pebbles 5 ft. 3. Yellow clay with limy concretions 3 ft. 4. Gray, soft sandstone pitted and water worn to bed of creek . . 8 ft. On the western side of the Brazos these clays are divided into blue and brownish clay with nodules of lime forming the upper division, and a yellow clay with streaks of sandstone and the 246 University of Texas Bulletin lime disseminated through the whole mass forming the lower division. Nodules of lime are rare in this lower division. Broken sandstones, or thin flat bowlders of lenticular form, appear in the upper blue clay, but these, while occupying a definite horizon, are by no means plentiful. The sandstones in the lower yellow clays, while irregular as to their longitudinal extent, are much better developed than those in the blue. The equivalence of the Lagarto to some portion of the Fleming found in the vicinity of Woodville has been suggested and is considered probable but there is at this time no means of positively determining this. LAFAYETTE This name, which was agreed on by Hilgard and McGee to replace the older name of Orange Sands, is here used for those deposits of gravels, sands, and clays often of characteristic orange color, which occupy the belt between the Fleming to the north and the Coast Clays on the south, between the Sabine and the Brazos, their stratigraphic position being be- tween the two formations named. To the northward of this main belt the continuation of these deposits are found in the uplands overlying the older deposits as a mantle and are there usually characterized by the presence of gravel foreign to the sediments which they overlie. Other deposits are found within the upland area which are of the same color and more or less of same lithologic character, except that the gravels are want- ing in them. Some of these are separated from the older sedi- ments by an erosion interval while others seem to grade grad- ually downward into the underlying beds. These may, biit probably do not, belong to the Lafayette. Chaeacteb and Deposition. The materials of the Lafayette are primarily sands and gravel of varying degrees of coarseness, with variable amounts of clay, locally pure and lying in thin layers, but, more often, clays mixed with sands. Graduations from pure clays into pure sands through all intermediate stages of sandy clays and The Geology of East Texas 247 clayey sands are met with, but the larger part of the deposits are of sands and clays mixed in various proportions. Deposits, which can be referred with certainty to the Lafa- yette, are practically never well stratified and seldom well as- sorted. Cross-bedding and pockety structures are common. In many places the bedding is irregular and wavy, exhibiting a structure resembling minor intra-stratal crumbling as is seen often in sub-aerial and lacustral sediments. This crumbling is seldom recognized except when thin layers of clays are inter- bedded with sandy materials. Gravels, when found, are either unsorted and unstratified, or are found in pockets in the clays or sands, or else exhibit rude stratification often in thin layers running out into the other materials, in some places there being but single lines of pebbles running out into the clays and sands. In the gravel is found quartz, chert, igneous rocks and silici- fied wood. Concretions of limonite varying in size from that of small shot to masses several feet across are common. Grav- els, sand, and clays are often cemented by limonite, derived either from process of secondary precipitation or from chaly- beate springs which deposit bog iron ore. The color of these deposits is very distinctive. The un- altered body color is red of various shades from orange to dark brick or Indian red. The purer clay portions are light blue or gray but the clays as noted above are subordinate in amount. The surface zone is frequently leached a lighter color than the underlying less weathered portions. Mottlings of gray and red are very characteristic of the clayey sands. When such mottling is encountered the gray, shades are confined to more clayey portions, while the sandier portions are red. This is, perhaps, equivalent to saying that the more pervious materials have their contained iron in the oxidized state and that the less porous contain iron in the reduced state, probably in the form of carbonate. Thin lenses of clay are gray in color when the interbedded sands are red. Balls of clay are gray and the enclosing sands red in many localities. Whether the red color was originally possessed by the sedi- ments before being deposited in their present situations or is secondary and subsequent to their deposition is a perplexing 248 Univei'sity of Texas Bulletin question. It may be that part of it is original and part is secondary, for we find residual soils of such older formations as the Wilcox and the Cook's ilountain that are as red as the typical Lafayette and the mottling would suggest that a part at least of the coloration is secondary, since in the mottled beds it is apparently only the more porous portions which have the red color. Roots of plants penetrating the "Lafayette" ma- terials decolorize the red beds, changing the iron back into the carbonate form. It is difficult to see how the red color can be assumed to be primary in that portion of the "Lafayette" which is undoubtedly transported detritus, for the red color is merely a surface coating of the individual grains and this would be worn off during any considerable transportation. The formation of red residual soils at the present time in the east Texas region would seem to indicate that the "Lafa- yette" sediments were laid down under climatic conditions es- sentially similar to those of the present. The Lafayette gravels were deposited on a peneplained sur- face. In places, as shown by the unconformity between these gravels and the underlying bed rock formations on the higher hilltops and divides, the peneplained surface was produced by denudation. In other places the peneplain may have been formed by deposition. That monadnocks of more resistant rock persisted above the general peneplain surface is demon- strated by the fact that hills and ridges like those of Irona, Sabine county. Mount Selman and other prominences near Rusk were never covered by the gravels. While it is possible that the Lafayette might have been laid down in a retreating sea to the littoral of which a constant sup- ply of proper sediment was furnished by fluviatile agencies there is an absolute lack of any evidence of this and the char- acter of the lieds rather indicates that the deposition was, for the most part at least, subaerial and the result of fluviatile action. Details op Sections On the Sabine we find in the top of Sabinetown bluff a ves- tige of the Lafayette depositional peneplain, the composition of which has already been given in connection with the Claiborne University of Texas Bulletin No. 1869 Plate XII. LAFAYETTE FORMATION. View near Colmesneil. The Geology of East Texas 249 section below MeClanahan 's shoals. This shows a basal gravel made up of flint and quartz pebbles from the size of a pea to an inch in diameter overlain by structureless clayey sand in mottlLngs of bluish-gray, reddish-brown, red and buff colors. The quartz pebbles are more abundant here than in similar deposits west of the Palaguache. Going westward from the Sabine to Milam, Geneva and San Augustine there is found a great thickness of Lafayette sand, often with ferruginous pebbles. In places the orange or red sand is interbedded with thin leaves of gray sandy clay. Two and a half miles sOuth-southwest of Geneva in the valley of Borregas creek, which is the principal tributary of the Pala- guache, there is another portion of the Lafayette depositional terrace consisting of three large remnants the tops of which cover several acres. These are made up of typical Orange Sands carrying large boulders of ferruginous conglomerate. The Lafayette has a thickness of 20 feet and probably more between Price Creek and Calcote postoffice, where the super- ficial 3 feet is dark red and the underlying material orange-red. It is characterized by the presence of many fine ferruginous pebbles and by cross-bedding. It is sandy but has the prop- erty of standing, up in perpendicular gullies 10 feet or more in height. The country is flat and most likely is a remnant of the original Lafayette depositional peneplain. The Lafayette under the west end of the bridge over the Attoyac is partially stratified and cross-bedded. Thin partings of gray clay separate massive and imperfectly laminated light- gray coarse loose sands stained yellowish-brown on the sur- face. Thin sheets and laminated layers of ferruginous-ce- mented sand are seen. The thickness of this section is 10 feet. A spring issues at its base and it is capped with soft ferrugi- nous-cemented dark brown conglomerate of ferruginous pebbles. The Lafayette in the vicinity of Arenosa postoffice consists of deep sand leached at the surface, but reddish underneath. There is much ferruginous conglomerate, sandstone and peb- bles in the Lafayette in this vicinity. 17-ET. 250 University of Texas Bulletin SANTA FE RT. SECTION Between San Agustine and Jasper the Lafayette is found in many cuts, overlying the Marine, Jackson, Corrigan and Flem- ing in turn. The exposures through the level Jackson country are but few. They are more numerous in the Corrigan and well shown in the Fleming. The unconformity between the Catahoula and Lafayette is well shown in the first cut north of Mile Post 85. At the base is 7 ft. of light gray sandy Catahoula clay. Above lies 10 feet of cross-bedded Lafayette. The contact between the two is irregular, small lenses and ridges of the Catahoula projecting up into the Lafayette. The latter is light brick-red in color. On and near the top of the ridge near Horton siding there are bodies of Lafayette ferruginous conglomerate. These are found at various places from north of Mile Post 81 to 1-5 mile south, mostly in rather thin layers some of which are laminated with thin layers of nearly pure limonite adhering to the thicker layers of grit or conglomerate. Some of the ferruginous con- glomerate is concretionary. At the summit, about 400 yards north of Horton, is a cut 20 feet deep in the Lafayette, which here is cross-bedded, with a minor amount of .gravel, and small balls and lenses of a light purplish clay running as curved laminae or as cross-beds. A few fragments of silicified wood, some of which are larger. portions of large trunks, may have been derived from the Catahoula, or may belong properly to the Lafayette. The Lafayette sand in many places is coarse and angular like that of the Catahoula. The presence of peb- bles indicates that at least some of the Lafayette was not de- rived from the underlying Catahoula, but was transported from some other places, and therefore that the Catahoula could not have formed a high ridge above the general level at the time the Lafayette was deposited, unless such ridge finally came to be completely covered by Lafayette sediments. Some of the silicified wood may really be indigenous to tha Lafayette. A number of the fragments are large and are not rounded as if rolled or water-worn but are splintered with sharp fractures. A mile and a half north of Jasper the road enters a gently TTie Geology of East Texas 251 rolling country covered by Lafayette with its usual character- istics of composition and structure. Occasionally some Lafa- yette pebbles are encountered in the swampy area. Irregular masses of small pebbles showing little evidence of sorting or stratification are embedded in a coarse cross-bedded sand. The pebbles are subangular to well rounded, average about an inch in diameter, .are arranged with the'ir longer axis and flat sides in a horizontal direction, and are composed of quartz, chert, quartzite, some igneous and metamorphic rock, mainly- fine- grained, and occasionally a pebble of ferruginous-cemented sandstone and "iron-ore." The surface one foot or more of the ten feet exposed in this cut is leached light brownish gray and the lower portion has light shades of yellowish-red with mottling between an irregular network of dark red and various shades of gray, the latter color being present especially where the composition is clayey. ANGELINA-NECHES SECTION In Jasper county east of Bevilport Ferry on the Angelina, the second bottom terrace is nearly 1^^ miles in width. Its river- ward limit is sharply defined from the first bottom or present liver plain, while its bluffward limit is obscure and merges grad- ually into .the upland. Between the eastward limit of the Port Hudson terrace and the town of Jasper the sole surface rock is the Lafayette with its usual composition and color. Pockets of quartzose and cherty gravel are numerous in the Lafayette in the neighborhood, and along the Jasper-Bevilport road there are cuts of ten feet or more in thickness. The depositional peneplain of the Lafayette, so well shown on top of the bluff 140 feet above the Neches river at Town bluff, is also well developed in the vicinity of Jasper and between that town and Bevilport and Bohler'g ferries in broad flat uplands separated by rather deep and sharp valleys. In the angle between the confluence of the two rivers it is dif- ficult to separate Lafayette from terrace deposits. Here the original Lafayette surface was reduced to a rolling one of smaU differential relief by the time the terrace epoch came on and there 252 University of Texas Bulletin is no abrupt break in profile at the line of contact of the two formations. There are high bluffs of 100 feet or more just east of the Attoyac on the Huntington-Hemphill road. These bluffs are capped by Lafayette ferruginous conglomerate, here overlying the Yegua, but farther south on the Angelina bluffs, near Old Zana post office (Caddell of ¥eatch's map) it caps the Jackson, while on the Gulf, Colorado & Santa Fe Railroad between Jasper and Horton, Jasper county, it rests upon the Catahoula. The materials on the Attoyac bluffs are quartz and chert, subangular to rounded, and silicified wood, which is angular. The cement is dark brown limonite and is locally quite hard. Town bluff on the eastern boundary of the James Perkins and Wesley "W. Hanks grants, central eastern Tyler county, rises 140 feet above the low water-level of the Neehes river. Its top, capped with Lafayette, is very fiat and has evidently suffered no erosion since the time of the formation of the Lafayette, depositional peneplain. The thickness of the Lafayette capping the bluff is approximately 40 feet. It is mottled, gravelly, clayey sand, with the surface one to four feet leached buff or gray sand and the underlying beds various shades of red with the lowest portions of an Indian red shade. At the edge of the buff cirque-like gul- lies or "gulfs", blunt-headed and perpendicular-walled or over- hanging, often have depths at their very heads of from 20 to 40 feet. This property of the Lafayette of forming perpendicular or overhanging cliffs is partly because of case-hardening, caused by the redeposition of iron salts, leached from its body, on sur- face exposures, possibly partly because of the deposition of sec- ondary silica, partly because of the Lafayette being clays or clayey sands which gives it tenacity and plasticity and probably partly because of the compact packing together of the constituent materials. Rejuvenation and deforestation, jointly or separately, have been responsible for the formation of these deep, steep and nar- row gullies in the unconsolidated clays and sands of the Corri- gan, Fleming, Lafayette, Port Hudson, and the later superficial accumulations. Black land prairies, never covered by timber growth, areas from which most of the timber has been cut, and cultivated or abandoned cleared fields are places where gullies The Geology of East Texas 253 have been formed within the memory of man and where they are still forming. They are also well developed in railway cuts and fills. TEXAS & NEW ORLEANS RAILROAD SEOTION South of Rockland and just north of Bridge 99-B there is a light gray sand and clay locally case-hardened and having a strong taste of alum. At the cut just north of Bridge 99-C there is at the base one foot of friable fine clayey sandstone, slightly case-hardened, overlain by four feet of loose shelly clay. The stratigraphic position of this member is not known. Beds lithologically similar are known to overlie all formations from the Yegua to and including the Fleming and to be overlain by the Lafayette. It may belong either to the underlying formation, or it may be later, representing the Oakville or some other forma- tion, or it may belong to the Lafayette, being a residually de- rived portion of that formation. From here the Lafayette forms the sur'face to Colmesneil. In the cut immediately north of Cima siding the Lafayette contains thin layers of laminated earthly iron oxide and perhaps carbonate. Here the Lafayette sands are cross bedded. The thin bands of dark brown, fine-grained, compact iron minerals are irregular in their distribution and do not run parallel to any one plane, but are rather irregularly waving beds not always in the horizontal plane. The structure of the iron minerals is botryoidal, mamillary, or laminated, often enclosing gravel or sand when nearest the pure state, or it may form only a blackish or reddish cementing material for the sand. The lower portion of the section, below the iron-bearing mem- ber, is cross-bedded sand often with a purplish red tinge on the surface. In places it is mottled and in all respects resembles the sand above the iron-bearing member. This upper bed is mottled red and gray and contains small brown concretions of sand cemented by iron oxide. The color of this bed is predom- inantly orange. Between these two is the laminated iron-bearing member oc- cupying an irregular zone from 3 inches to 3 feet in width, the individual layers averaging from 1 to 2 inches in thickness and being separated from each other by mottled sands like those above 254 University of Texas Bulletin and below the iron-bearing member. A concretion 3 feet in length and with regular surface was noted. In the cut and fill at Cima siding there is a 30 foot section of Lafayette case-hardened clayey sand, standing in perpen- dicular walls. The surface leached zone, yellow buffi below to light creamy gray on the surface, is from 1 to 6 feet thick. The underlying sand is dark brick-red. Some cross-bedding and mottling is noted in the upper portion. The Lafayette is well exposed between the top of the grade at Cima siding and Colmesneil. The gravel is arranged in patches of small size or rather uniformly distributed for short distances through the clayey sand. It is in brief, quite ir- regular in its distribution and amount. Long deep railway cuts will be seen that are free from gravel and again there may be local lenses and pockets almost. entirely made up of gravel. Or, it may be sparsely distributed or arranged along lines of stratification. The pebbles are rounded or subangular and are principally quartz, chert, and silicified wood. Iron-sand concretions, representing local secondary deposi- tion of iron, and varying in size from that of a pea up to ir- regular friable masses of several square feet are locally found. These generally have a darker shade of red than their surround- ings. Sometimes tilted layers, simulating dip and parallel with each other, are encountered, in some places their structure showing a local unconformity with the underlying or overlying structureless or imperfectly bedded Lafayette. These may represent channel deposits. In the region between the Texas & New Orleans and Houston, Bast & West Texas Railroads the surfieial gravel and unconsol- idated structureless reddish clays and sands capping the tops, and sides of elevations are referred to the Lafayette or Orange sand. Overlying and contiguous to the outcrops of the Marine f9rmation the gravels contain many of the ferruginous sand- stone concretions of the Marine but elsewhere the gravels ar& mainly round, subangular, or egg-shaped pebbles of quartz or acidic igneous rock, with here and there a fragment of meta- morphic rock. The pebbles occur in great abundance near the confluence of the Bayou Attoyac and the Angelina river, both The Geology of East Texas 255 mantling the surface of the triangular shaped area between the streams and southeast of the Angelina bertween Warsaw and "White City, Angelina county. While many of the contacts between the Yegua and the La- fayette are unconformable one was found in a creek in north- ern Angelina county in which no unconformity appeared. The bluff is made up of alternating layers of gray and brown sands and chocolate clays belonging to the Yegua. Overlying these beds without apparent unconformity is found the mottled surfieial member. The lower 3 feet is a layer of brick-red loose sand with very small non-continuous disc-like streaks of very light gray clay. It is overlain by 4 feet of medium-indurated reddish brown on surface and yel- lowish-brown underneath, medium- grained, rather finely lami- nated sandstone. The upper 1 foot of this 4 feet is laminated, concretionary, and contorted very ferruginous sandstone with its least altered portions composed of thin seams of black iron 11/4 inches and less in thickness grading out into dark brown sandstone to yellowish-brown sand as leaching and oxidation gradually becomes more prevalent. The whole transition takes place generally in less than an inch. HOUSTON, EAST & WEST TEXAS RAILWAY SECTION The southernmost exposure north of the Angelina river on the line of the Houston, East & West Texas Railroad gives a section of about 20 feet of apparently horizontal strata. The lower portion of the section is made up of thinly laminated arenaceous chocolate-colored and drab shales containing leaves, among which were noted Salix and Ficus (?). These belong to the Nacogdoches.^ Overlying the shales are Lafayette gray- ish structureless arenaceous clays, which, when exposed to surfieial weathering, are generally mottled with streaks and blotches of bright brick-red. Interspersed with the clay layers are clayey sands, in general unconsolidated but locally ce- mented by ferruginous material, which, in common with the ' A fuller description of these beds was given in connection with the Nacogdoches heds. 256 University of Texas Bulletin clays, locally contain ferruginous concretions and small rounded pebbles coated with dark purplish iridescent iron oxide. When unaltered the clay and sand member is bluish- gray to buff in color, but, on weathering, its contained iron stains the rocks various shades of brown either in a uniform manner or in streaks and blotches which impart to the surface exposure a characteristic mottled appearance. The sands are fine in texture. The description of the sand and clay series with interbedded lenses of chocolate and drab shale, will serve as a general one for the uppermost series of beds exposed in southern Nacogdoches county, and as far south in Angelina county as a point half way between Piatt siding and Mantoi\ station on the Texas & New Orleans railroad. The Lafayette gradually looses its red color, becoming more grayish,- as the distance from the outcrop of the ferruginous Marine group increases. There is also another notable change as one goes southward and that is in the constitution of the materials of the gravels. Before the Neches river is reached on the southward journey all pebbles of Mariae ferruginous sandstone have disappeared and it is only the more resistant materials such as quartz, crystalline rock, chert and silieifled wood, that remain. On the northwest corner of the J. M. Deane league a chert pebble with a Paleozoic fenestelloid bryozoan was noted. At Cleveland, Liberty county, the reddish-colored Lafayette is exposed in low knolls of small extent which are inliers com- pletely surrounded by Port Hudson. Similar inliers are found on the Houston, Bast & West Texas railroad from Shepherd to Splendora and the Lafayette probably extends some' dis- tance south of Splendora. A cut one-half mile north of Splen- dora shows 2y2 feet of light buff fine sandy clay full of small rounded concretions containing a very small percentage of iron. The exposure is lightly mottled. At Mile Post 39 (1% miles south of Nimrod) there is 4 or 5 feet of Lafayette, very faintly mottled and having small rounded pebbles of quartz and igneous rocks. This cut is on a low ridge just south of the San Jacinto river. Lafayette is found in a cut on a low hill one mile south of Cleveland as 6 feet of mottled gray and red clayey and gravelly sand. The gravel is fine and is almost TM Geology of East Texas 257 entirely composed of fine rounded pebbles of brownish fer- ruginous sandstone. There are a very few pebbles of quartz. In a flowing well at Gladstill, one-half mile south of Nirarod the following strata were encountered: Thickness Depth Feet Feet Surface soil 2 2 Red and yellow clay ■ • 8 10 Gravel and sand 12 22 Red clay 3 25 Sand and gravel 9 34 Yellow clay ■ ■ . . . 12 46 Sand 19 65 Clay 6 71 Sand and gravel 17 88 Clay 9 97 Sand 8 105 Clay 7 112 Hard shale 18 130 Gumha 9 139 Hard shale and sand 8 147 Sand and gravel 16 163 Rock ; 3 ie« Gumho 27 193 Red shale and sand 20 213 Rock 1 214 Gumbo 9 -IZZ Sand 29 252 Rock and shale 13 265 Sand 18 283 Rock 1 284 Hard shale 14 298 The first 163 feet of this well section is Lafayette. Coarse brown sand and fine pebbles of Lafayette were found in the drillings scattered about the well. In a well at Cleveland, 390 feet deep, an abundant supply of water is found which rises to within 5 feet of the surface. The Lafayette is about 150 feet thick in this well, giving it a south- ward dip between here and Nimrod of about 18% feet per mile. Alternating layers of rock (probably sandstone) and softer ma- terial of the Fleming were found between 150 and 390 feet. The water stratum yielding the present supply was found at 350 feet. 258 University of Texas Bulletin Overlying the Tegua west of the Houston, Bast & West Texas railway the Lafayette is usually brown or orange colored ferru- ginous and gravelly sands underlain locally by shaly light brown clay with fragments of gray clay possible derived from the un- derlying Tegua. In places the sand carries small pellets of dark brown limonite concretions and at times is cemented with limo- nite. Cross-bedding occurs and occasionally very thin lenses of grayish clay are embedded in the sands. There is a covering of Lafayette at Kennard Mill (Central Coal & Coke Company) and at the town of Ratcliff. Overlying the Yegua is 5 feet of cross-bedded sand, the unconsolidated por- tions reddish-brown in color with thin streaks and beds of more sonsolidated light gray sand. Overlying this is 4 feet of lam- inated brown clays and sands. Roark's gravel pit is 3 miles north of Cleveland and about the some distance from the Gulf Colorado & Santa Fe and Houston, East & "West Texas Railroad tracks. This gravel is fine and similar to that found at Coldsprings and Urbana. The gravel is mixed with coarse whitish sand. The Lafayette is exposed in a cut at Mile Post 53 on the Houston, East & "West Texas Railway. Wells at Napier get a good supply of fresh water in sand and gravel at a depth of 65 feet. Gravel is also found on land be- longing to C. B. Udell four miles southwest of Shepherd on the Evergreen road and also on adjoining land belonging to Mr. Bird. It has a coarse brown sand matrix, but will require pros- pecting to show its depth and areal extent. Gravel was noted at a place between 3 and 4 miles west of the Houston, East & West Texas Railway near Westcott and Normanville. There are also gravels on the surface- at various places on the Shepherd- Everett road. Local deposits of gravel are found all the way between Shepherd, S,an Jacinto county and Willis, Montgomery county. A Lafayette ridge is followed by the road between Kelly's switch (Bareda) and Huntsville. It consists of fine deep-white sand and mottled red and gray clayey sand. The high ridges in the vicinity of Coldsprings, San Jacinto county are covered with Lafayette sand ancJ gravel, locally ce- mented with limonit]e into grit and conglomerate. The dividing ridge between the Trinity .and San Jacinto drainages between Oakhurst and Coldsprings is covered with Lafayette gravel. The Th'e Geology of East Texas 259 south bluffs of the Trinity valley, north of Camilla, San Jacinto county, are covered with coarse reddish and mottled Lafayette sand containing small fragments of whitish clays and petrified logs. The upper course of San Jacinto river in southern San Jacinto county is incised to a depth of 10 feet below the Lafa- yette surface. The Lafayette begins a short but undertermined distance south of Coldspriiigs and consists of the usual mottled sandy and gravelly facies. At the head of Town creek at Cold- springs there is fine very plastic sandy clay of a dark hematite- red color. Springs issue from the plane of contact between the Fleming and the Lafayette. Here the bluffs of Lafayette are from 35 to 50 feet in height recalling the "Gulf" of McGee. INTERNATIONAL & GREAT NORTHERN RY. SECTION On tbe International & Great Northern Railway there are sim- ilar occurrences of the Lafayette. Mottled red Lafayette sand with much gravel is found on the summit of the grade on the International & Great Northern Railway at Mile Post 78 in southern Walker county. Much Lafayette is found on the Huntsville branch of this railroad between Phelps and Hunts- ville. In its more southerly exposures the Lafayette has flat, very gently rolling, often swampy surfaces. The southern limit of its outcrop can be distinguished from that of the adjoining coast clays by a low rise, with light undulations, but resembling, on the whole, a maturely dissected terrace. The Lafayette-Port Hudson contact on the International & Great Northern Railway is just north of Spring, approximately at the north line of Harris county. Wpst of the Trinity river outliers of Lafayette are more numerous yphere they overlap the Fleming than they are on the other formations. The materials of the Lafayette proper are finer-textured in the region of their outcrop between the areas of the Fleming and the Port Hudson (coast clays) than they are in the isolated outliers farther north. This decrease in coarseness is very gradual, but it is undoubtedly true in a general way. The contact between the Lafayette and Port Hudson is hard to define owing to the extensive overlap of the latter on the eroded 260 ' University of Texas Bulletin surfaces of the former. At the west near the Brazos, where the country is mere or less open the contact can be traced by the topography for the Port Hudson peneplain is' succeeded by a very low rolling Lafayette country of appreciable, though slight, relief. To the eastward, however, the country is more thickly timbered and the tracing of the contact is more difSeult. On the International & Great Northern Railway, Madisonville branch, the southern limit of the Lafayette is at Willow, 34 miles from Houston and 11 miles northwest of Spring. The topogra- phy northeast of Willow is very gently rolling with undrained depressions. The stream gullies are sharp and 10 to 12 feet deep. Some of the Lafayette is very light buff or creamy clayey sand, mottled with red and with small ferruginous concretions. On the Houston & Texas Central Railroad the first Lafayette is found at Mile Post 30 northwest of Houston. This is the site of the first appreciable rise from the coast prairie. To the west- ward the Sun Mounds are inliers of Lafayette in the Port Hud- son. The more marked rolling topography begins between Mile Posts 39 and 40, just south of the south line of Waller county. The relief gradually increases northward. The northern line of the Lafayette is a short distance south of Howth. There is a fine exposure of Lafayette sands on the Texas & Brazos Valley Railroad where it crosses the International & Great Northern Railway. CLOSE OF NEOCENE In this region the surface of the Lafayette shows considerable erosion prior to the deposition of the fossiliferous marls referred to the Equus beds horizon, which is srupposedly basal Pleistocene, and it is involved in the diastrophic movements which preceeded the deposition of the Port Hudson. For these reasons the Lafa- yette is here made the uppermost member of the Neocene, al- though it is sometimes referred to the Pleistocene or regarded as bridging the Pliocene and Pleistocene. North of the Lafayette-Port Hudson contact, the amount of movement apparent is not very great and seems to have been simply a gradual regional elevation. To the seaward, although the surface is a great peneplain, drilling shows that the orogenic TJie Geology of East Texas 261 movements were intense before the deposition of the .mantling clays. It indicates in fact that at the close of the Tertiary we had a repetition, perhaps on a somewhat grander scale, of the movements which accompanied the close of the Cretaceous. As has been stated, the movement at end of Cretaceous timq was sufficient to create the Cretaceous domes and the Sabine Peninsula through local elevation of the Upper Cretaceous sed- iments 2500 to 3000 feet. These elevations were all in the sea> ward margin of the Cretaceous land mass which in itself showed comparatively little change of level. These domes were almost without exception subsequently mantled by clays and sands of the Tertiary, which entirely masked their character and but for later erosion or the searching enquiry of the drill their presence might not have been suspected. The same is true in great measure of the Coastal domes. Some few of them may now make themselves known by a slight eleva- tion at the general surface, the Sun Mounds near Hockley and Damon Mound being the highest of them, but for the most part they are either little distinguishable above the general level of the prairies, or only found by drillng. The Sun mounds and Damon Mound, which are typical domes and rise from 70 to 100 feet above the prairie, are capped by Lafayette. Some of the buried domes also show beds of gravel which are properly refer- able to that formation. These buried domes are covered by va- riable thicknesses of the Coast clays, ranging from one hundred to several hundred feet, while between the domes we find as much as 2500 feet of materials referrable to the Coast clays of the Port Hudson. The irregularities of the substructure is therefore fully as great as in the case of the Cretaceous domes. Possibly nothing could bring out the differential movements that have taken place in this coastal area since the Miocene dep- osition more clearly than the fact that while the Pliocene ( ?) brackish-water fauna which occurs at Burkeville 150 ft. above sea level is found in abundance at Terry, 66 miles south, at a depth of from 3,000 to 4,000 ft., the marine Miocene fauna which occurs at Saratoga at a depth of 1,000 ft. is only 2400 ft. deep at Galveston, 74 miles south of it. It seems clear, therefore, that at the close of the Neocene the coastal area of east Texas was subject to extensive oscillation. 262 University of Texas Bulletin and it is these movements rather than those of earlier date that are directly connected with the formation of the domes and folds found here. There are a number of these Coastal Domes already known and they appear to occur in somewhat regular alignments along general northeast-southwest courses, which is approximately the direction of the chain of Cretaceous domes which has been men- tioned. / That they are of orogenie origin is fully proven by their com- position and by their relation to adjacent deposits. They are in all cases, so far as now known, composed of a core of salt or of gypsum or anhydrite (with which deposits of native sulphur are sometimes associated) which plugs have been forced up through beds of Miocene and later age. This relationship has been definitely shown to exist by the drilling done at Humble and similar domes. The relation of the bodies of salt, gypsum, and sulphur of these domes to the surrounding sediments indicates that these masses have certainly penetrated 2,000 or 3,000 ft. of the sedi- mentary strata. The clays sands, and limestones immediately adjacent to or overlying them are tilted at comparatively high angles for this region, the surrounding sedimentaries dip away from them at lower angles, and beds or sills of salt and gypsum extend from the main mass out into the surrounding beds, as sometimes happens with plugs of basalt coming up through sim- ilar materials. Up to this time basaltic matter has not been definitely proven to exist in connection with these domes. Its place is taken by the salt, gypsum and anhydrite. In connection with the close of the Eocene attention has been called to the probability of the accumulation of considerable deposits of these substances at that time. Salt becomes plastic at temperatures far below those necessary for the production of siliceous lavas and would lend itself much more readily to the work of filling any voids caused by crumpling or assisting such crumpling. Salt stocks of this character have long been recognized in the Carpathians and else- where in Europe. In this connection, the following suggestions regarding the domes are made: The Geology of East Texas 263 The domes are separable into two series: The Interior domes and the Coastal domes. The bodies of salt found in connection with the Cretaceous domes were probably deposited during the Lower Cretaceous or the interval between the Lower and Upper Cretaceous and the uplift which formed the domes occurred at the close of the Cre- taceous. The salt of the Coastal domes was deposited at the end of the Eocene or beginning of the Oligocene and the movement which resulted in these domes took place at the end of the Tertiary. The connection of the Coastal domes with the oil fields of the region is in some measure accidental. The close association of the oil, gypsum, salt, and sulphur in some of the domes has naturally suggested the' idea of a common origin or a close relatonship in origin, and this has been widely discussed. "Were this true, the oil should be found in connection with all such domes, and such is not the case. We have oil pools where there is no dome and where no salt has been found, and we have numerous domes and bodies of salt, gypsum, and sul- phur without any accumulations of oil. Chapter X QUARTERNARY PLEISTOCENE The Pleistocene of East Texas includes the river deposits of the inland belt belonging to the Columbia and their coastward continuation, the Coast clays or Port Hudson, which Kennedy called the Beaumont clays. They rest unconf ormably on the Lafayette. The Columbia phase embraces those deposits which form the second bottom terraces of the main streams. On the Sabine, An- gelina, Neches and Trinity rivers they extend well toward heads of the streams. The upland deposits of this stage are of the character of the loess. At the base of these deposits there is usually a layer of gravel derived from the erosion of the Lafa- yette. The deposits themselves are clays and silts of various col- ors containing small limy concretions and some gravel. Shells of the Unio or fresh-water dam are found in them and blocks and logs of cypress, which are but little altered, together with the bones of the mammoth, horse, ground sloth, etc. Nearing the coast these beds grade into clays of the Port Hud- son. These are heavy clays of various colors with small lime concretions and local lenses of sand and sandy clays. In places cypress logs are found in these clays at considerable depth and shells, similar to those of the present bay shore, oecur in them at places. GENERAL CHARACTER As one travels from north to south from Nacogdoches to Polk counties, he passes gradually from a region which is mostly bed rock upland to one that is mostly alluvial lowland. The divides and interstream ridges of Polk county stand out as much promintoried peninsulas in the bottom lands of the creeks and ridges — the sea of their ovni debris. South of the Nechse-Trinity divide the southward sloping interstream ridges lie above the bottoms as partially sunken headlands on a sub- The Geology of East Texas 265 merged sea coast. Between the uplands and the bottom lands there is in most places a noticeably abrupt break,, a break in the profile rather too sharp to be explained solely as brought about by the processes of an uninterrupted cycle of erosion. The bed rock formations are not sufficiently resistant to cause this break. The valleys are too broad to explain the almost contin- uous fringe of steep bluffs between the broad bottoms as entirely the product of lateral planation of meandering streams. There is a mature, in some cases even a youthful, topography of the upland areas with an extreme old age topography of the lowland areas. The topography is partially drowned. It is not all the product of one cycle of erosion or there would be more of a continuous, less perceptible, graduation between the divides and the stream courses. This apparently implies a former base level higher than the present and especially a rising of the base at a rate greater than the down-cutting of subaerial agencies. A former base level lower than a succeeding one, which was responsible for a differ- ential relief greater than the present one between alluvial bottom and bed-rock divides is apparently implied. This epoch of rais- ing of base level is the Columbia-Port Hudson. ANGELINA-NBCHES In the upper portion of the Trewick's bluff, and comprising the whole of the exposures in Perigue and Carlisle bluffs, as well as the low knobs outcropping above the level of the "saline" crossed by the Angelina river one mile east of the Texas & New Orleans Eailroad bridge over the river there is a hard conglom- erate, with pebbles mainly of quartz and igneous rocks, and sub- ordinately of ferruginous sandstone in a matrix of coarse sand grains, cemented by iron carbonate and iron oxide. The occur- rence of this conglomerate in these bluffs together with the great amount of loose gravel found farther down the valley of the same river may indicate that we have here a formation somewhat simi- lar to the Columbian of the southwestern Atlantic States derived from the surficial beds referred to the Lafayette and deposited by the Angelina during a former time of alluviation of its flood- plain. 18-ET. 266 University of Texas Bulletin The upper limits of the river terraces (Port Hudson?) are hard to define in the triangular region between the Angelina and Neches rivers just above the junction of these two streams, be- cause the upland is very low and only very moderately rolling and merges insensibly into the second bottoms. The second bot- tom can be distinguished from the first and lower bottom by its superior height and its covering of "piney woods" probably sig- nifies better drainage than is possessed by the first bottom. But east of the Angelina, in Jasper county, east of Bevilport Ferry, the second bottom, terrace is nearly li^ miles in width. Its river- ward limit is sharply defined from the first bottom or present river flood-plain, but its bluffward limit is obscure and merges gradually into the upland. TRINITY EIVEB Three terraces, including the pesent fiood-plain, are well de- veloped on the Trinity, at Westmoreland and Clarke bluffs. The height of each will average probably close to 25 ft. The prairie level terraces ae still higher and there are traces of a still lower one being developed in the present fiood-plain. At Westmoreland bluff in western Houston county the second bottom alluvium overlying the Tegua is mottled grayish and rusty sand containing gravel with the usual ferruginous-cemented gravel layer at the base. The first bottom below this bluff is black waxy calcareous alluvium derived from the Cretaceous. It appears probable that the second bottom alluvium was laid down before the Trinity river had cut back into the Cretaceous. Just to the west of the head of Spring creek, near Westmore- land bluff, a minor terrace level between the first and second bottom is noted in a poorly developed bench with its surface about 8 feet below that of the second bottom. It is narrow but has a distinct step downward from the second bottom and heads of gullies have cut back into it nearly to the second bottom. The total number of terraces at Westmoreland bluff is either five or six, five if the proirie level is not counted and six if it is counted. Of these, three or four are main terraces and two are minor terraces. The remainder of the Spring creek exposures, near its head, The Geology of East Texas 267 are in brown sandy alluvium, containing Lafayette-derived peb- bles. This gravel layer is almost universal at the base of the terrace alluvium along the Trinity river from Alabama bluff to Liberty county. The creek shortly comes to an end in a blunt- headed gully. Above the head of this gully is the usual vestige of an older valley with the gentler slopes and gradienf of an older erosion sub-cycle. The first and second bottoms are very well developed in the vicinity of Hyde's bluff. The second bottom soils are either brown sand or black sticky clayey laminae. The underlying ma- terial of the second bottom is dark brown with small white calcar- eous nodules. Underneath this subsoil layer the alluvium is light buff in color. Negro creek which heads at Volga postoffice, shows some inter- esting exposures of terrace materials. The exposures near the head show 4 feet of light creamy-gray sandy clay with a very few white calcareous nodules. The lower portions of the creek's course show exposures in terrace material, one of which is 20 feet thick and composed of light gray, medium-grained sand, with very poor bedding. There are contained in it a few Lafayette- derived pebbles. It weathers to brick-red near the surface and locally is mottled. The upper one foot is leached to .a brown color. At another exposure farther down the creek the base is very plastic slaty blue clay, cracking much when dried. It is overlain by mottled brown and gray blue sticky clay weathering russet brown, above which is light brown sand. There are a num- ber of small flood-plain lakes in this region as well as lakes and swamps on the higher terraces and valleys of the larger creeks. The top of Pine bluff below the mouth of Negro creek shows : 1. Alluvium with calcareous nodules, light gray at base but brown above 15-20f t. 2. Ferruglnous.cemented Lafayette-derived conglomerate with casts of Unios 55 ft. Dark brown and brownish gray plastic clay with calcareous nodules outcrop on the edge of the terrace where the railroad spur to White Eock Locks enters the Trinity first bottom one mile south of its junction with the main line of the Beaumont & Great Northern Railroad and a section 10 feet thick is ex- 268 University of Texas Bulletin posed. In the western end of the third cut on the Beaumont & Great Northern Railroad west of the bridge over White Rock creek is a brown elay with small calcareous nodules belonging to the second bottom. At White Rock Shoals on the Trinity river excavation for the base of the lock on the north bank resulted in the unearthing of remains of mammoth (Elephas) and of a large horse (Equus), of Pleistocene age. The largest tusk of the mammoth measured 9 feet 6 inches in length and 14 inches in circumference at the base. •The podial bones were 12-13 inches in diameter at the socket. The scapula, ribs, teeth, limb bones and both tusks of the mam- moth were found, but these were very friable and rapidly crum- bled on exposure to the air. These remains are important since they give evidence of the Pleistocene age of the first bottom of the Trinity river. The fact that a number of bones of the mam- moth were found together indicates that the position in which they were found was the original resting place of the remains. They indicate that the portion of the first bottom in which they were embedded is neither older nor younger than the stage of the Pleistocene in which these mammals lived. The reddish clayey sand exposed in the higher banks of Kicka- poo creek near its mouth is alluvium of the Trinity second bot- tom. Brownish clay with calcareous nodules, probably second bottom material, is found between Mile Posts 15 and 16 of the Beaumont & Great Northern Railroad. At Eastham's Plantation, 13,000 acres in extent, and situated in the southwestern corner of Houston county, the alluvium of the second bottom, here so far down stream and so high as not to be subject to overflow, is locally 30 feet in thickness with the usual gravel layer at the base. The level of the second bottom terrace is 55 to 60 feet above that of the first bottom. Both terraces are covered with black land and underlain by brown sandy clays with calcareous nodules. The Columbia is well exposed further south on the Trinity river in the vicinity of Drews landing, eastern San Jacinto county, where it unconformably overlies the Fleming with a basal layer of Lafayette-derived pebbles overlain by brown clayey second bottom alluvium. Sections of light yellowish- brown sandy clay 5 or 6 feet thick are seen along Big Creek The, Geology of East Texas 269 on the Shepherd-Drews Landing road. The Columbia or second bottom has a wide area west of Drews Landing. The following section was made on the west bank of the Trinity one mile below this place: Top. 1. Light yellowish-brown, fine, sandy alluvial clay, gray at top. Mastodon remains, consisting of limb bones, lower jaw bones, and 19 teeth were found near the base of this member 30 It. 2. Much cross-bedded, medium-grained yellowish-brown sand locally indurated. Its base marks a line of springs 4 ft. One mile upstream from this locality the Port Hudson second bottom bluffs face each other on opposite sides of the river. Between these two places there are stagnant ox-bow. lakes on the first bottom. Portions of the surface of the Port Hudson depositional peneplain may be seen between Drews Landing and Shepherd. The Coast Prairie is a depositional peneplain of the Port Hudson group. BiEAUMONT CLAYS Kennedy 's description of these clays is as follows : Overlying the Lafayette gravels and sands there is a series of yellow, gray, blue, brown and black clays with brown sands. There are also occasional deposits of red clay. These beds are sometimes thinly stratified or laminated, but frequently massive. The laminated beds are usually interstratified with thin beds of blue and gray or grayish-white sand. The clays carry considera- ble quantities of calcareous nodules irregularly distributed, in many places shells of Pleistocene or Recent age, and great quan- tities of decaying wood in the form of tree trunks, bark and leaves. Among these the cypress appears as the most prominent, and among the invertebrate fauna found the Rangia cuneata (Gray) and an undetermined oyster are the prevailing forms, in these clays the calcareous nodules do not appear to have any definite position. It is true that they always accompany the blue clays, but they are always found scattered in small pockets and occupying irregular patches a few acres in extent. It is pos- 270 University of Texas Bulletin sible that by some chemical action during or after the deposition of the clays the lime had been segregated into small depressions or softer portions of the clays.^ The generally low flat condition in which tljiese Beaumont clays occur render attempts to unravel their structure with any degree of certainty somewhat diiBcult. They, however, are by no means structureless, as the whole of the beds carry sands occupying very irregular positions and lying in very irregular forms. Drilling has shown some of these sand deposits to lie in the shape of short, rather dumpy, or mound-like lenticles, others elongated and rather thin, while yet others form regular beds extending a mile or more in length. The clays themselves are also irregular. In places these occur in a massive form, giving rise through their toughness and tenacity to the term "gumbo" so frequently used by drillers. Often within the middle of these ' ' gumbo' ' deposits there occur pockets of thinly laminated shaly looking clays, sometimes intermixed with laminae of sand and frequently carrying small quantities of oil. These are the shales and oil shows so frequently recorded in the logs of wells drilled throughout the region. These pockets of "shale", while nu- merous, are by no means regular as to extent or horizon. In some wells they may occur several times, while in the neighboring wells they are absent. Another peculiarity regarding these Beaumont clays is tha form of the lime found in them. Towards the upper surface and throughout several hundred feet of these clays the lime appears almo'st altogether in the form of carbonate. At depth this car- bonate gives place to sulphate and small isolated nodules of amorphous gypsum are by no means rare. At some localities drilling has shown the gypsum to be in beds from two to fpur feet thick, but its areal extent is usually circumscribed. Decayed wood is abundant throughout these clays. This often shows in an almost fresh condition as if it had only been buried a short time. In other localities the decay may be said to be complete, and in some places, particularly in the vicinity of the domes, the wood may be described as carbonized, but not lig- nitized. Wood brought up in several of the drill holes at Bryan Heights from a depth of over 300 feet was in this condition. Throughout the whole formation the wood is never silicified. In ^U. S. G. S. Bulletin No. 212. The Geology of East Texas 271 this respect it is entirely different from any fossil wood found in the underlying- formations, and any silicified wood found may be considered as extraneous and has reached its position in asso- ciation with the gravel in which it is usually found. Throughout the whole of the area occupied by these Beaumont clays the only means of obtaining any information regarding their structure or the thickness is by means of wells drilled in the search for oil. Unfortunately, few of the logs are kept with any degree of precision, the records rarely showing the color of the material passed through or the character of the rock encountered when such is met with. These conditions render it often difficult to determine to what division the materials passed through belong. However, as the Beaumont clays carry but little gravel and the sands are usually thin, in all probability the appearance of heavy gravels, sands and rock shows that the drill has encountered some underlying formation. Attention must, however, be drawn to the fact that as the Lafayette extends seaward it loses much of its landward struc- ture. In its seaward extension it assumes a more clayey and sandy phase, the gravel deposits gradually become thinner and finally disappear, the sands thicken to some extent, but even these, in a great measure, lose their identity and become sand- stones which eventually grade into a clay. The Coast Clays are found on the Coldsprings- Cleveland road four or five miles northwest of Cleveland where they occupy a low flat country whose surface is interrupted here and there by small low knolls of Lafayette. The soil of the Coast Clays is a very light buff, very fine, sandy clay loam, forming, when dry, deep, loose and powdery dust of light weight. Tarkingfton Prairie east of Cleveland is a portion of the Coast depositional peneplain; It extends from four miles north of Pel- ican Station on the Gulf Colorado & Santa Fe Railroad southward to the Gulf and is cut into minor prairies by many peninsulas of forest. The Coast Prairie, on the Galveston-Longview branch of the International & Great Northern Railway extends as far as Spring creek on the Harris-Montgomery county line. It has in this vi- cinity its usual characteristics, a monotonous flatness, broken only by low circular mounds and smaller lower ant hills; open 272 ' University of Texas Bulletin spaces densely covered with grass and low herbs; with patches of post oak and scrub pine. Between Grapeland and Mile Post 17 the exposures are mainly gray or buff, loose, fine sand or silt, which resemble the loess. They are underlain by Lafayette which is found at the top of the grade in the two cuts north and south of Salmon, the southern cut being at the Houston-Anderson county line. The loess-like exposures are of fine materials. They are soft and have the property of standing in perpendicularly cut banks, such as would hardly be characteristic of other materials of such fine texture. The difficulty is to distinguish between this loess and loose fine leached residual sand derived from the older formations. At any rate, it can only be expected to be found on these high divides overlying deposits of Lafayette in situ. Since the deposition of Port Hudson the deposits have been greatly eroded as a consequence of regional uplift. The first, second and third bottom terraces so comimon to the Trinity from Houston county southward and southeastward are cut in the Port Hudson deposits. Whether these terraces mark definite ■stages in the physiographic history of the coastal plain can not be determined until the lower river valleys and the country south of the Lafayette outcrop have been investigated in more detail. SURFACE FEATUEBS SALINES AND MOUNDS Two striking features occurring throught this region and which are probably of Pleistocene age are the salines and Mounds. The salines are depressions of greater or less areal extent and of varying depths which are usually ponds, lakes or marshes during the wet seasons but form dry spots more or less salt- incrusted during the dry seasons. Some are entirely barren, others support a scattered growth of tufts of short grass or salt- loving plants, whilfe the larger ones form palmetto flats. A few have their surfaces dotted with small mounds. Even when dry at the surface the salines are moist a few inches below and the ■efflorescene is largely sodium chloride or common salt. The Geology of East Texas 273 These salines appear to be entirely wanting in the area occu- pied by the Mt. Selman and Cooke Mountain formations and are found only in connection with the palustrinal deposits of the Wilcox, Yegua, Jackson and Fleming: The mounds of the salines are low, varying from two to four or five feet in height, circular to elliptical in outline and from ten to forty feet in diameter. The soil of the mounds is a loose fine sand which is more loose and porous than that of the lower surface from which it apparently does not diifer in other re- spects. The mounds persisting above the general level have bet- ter drainage. The mounds are frequently a mass of ant-hills and on the lower surface are conical ant-hills from a foot to fifteen inches in height. Four and a half or five miles southwest of Burke, about seven miles from the Neches river, is a low swampy area with "quak- ing bogs" which are locally called "sucks". Judging from the bones scattered thereabout, the bogs have been the graves of a number of cattle and other animals. The quaking portions of the bog are elevated from four inches to a foot above the sur- rounding surface. They will shake when one treads over them or stamps upon them. The surface layer is hardened and cracked. Underneath there is a light blue liquid mud mixed with a small quantity of sand, in which a pole was easily pushed to a depth of twelve feet without striking bottom. In the dried surface portions of one of them a sticky elastic substance re- sembling gelatinous silica was noted. The quaking portions are from four to twenty-five feet across. On the surface of some of the mounds small ferruginous pebbles were found. A brownish fine sand (perhaps quicksand) was brought up to the surface on the end cf. a pole. On stirring up the liquid mass bubbles of non-inflammable gas rises to the surface. The blue mud has the odor of sulphur. Small mounds in actual process of formation were noted one and a half miles southeast of Lovelady on the John Forbes grant in the postoak upland near the h'ead of a small western tributary of Gail creek, known as San creek. Here, in a space some sixty feet in length, underlain by Yegua sand and light gray badland clay, are a half dozen small mounds close together and making up an elongated compound mound. From a half dozen small 274 University of Texas Bulletin crater-like vents forming the summits of the mounds water in small quantities slowly oozes out, bringing upward with it ma- terials varying in composition and texture from very fine clay to medium-grained sand, dark blue in color when fresh and a tawny yellow on the surface. The phenomena resembles closely those of a very quiescent stage of mud volcanoes. Forty feet of 2-inch pipe was pushed by hand down one of these vents without reaching bottom. A resident of the vicinity informs me that the locations of the vents have migrated during the last thirty years and a few yards to the westward of the present vents are traces of former vents which have now dried up. The vents are ten feet to fifteen feet in diameter and rise two or four feet above the general level. They have been the graves of animals which have bogged down in them. At the time of visit no gases could be seen escaping from these vents, but it is reported that in , former times bubbles of gas were seen to escape from them. It is possible, however, that these bubbles were merely of air, which came to the surface as one trod on the quaking ground of the immediate vicinity The "suck" in the Neches river bottom near Blix, western Angelina county, is similar in characteristics to the more pronounced mounds near Lovelady, but it is worthy of note that the one locality is on the uplands and the other in the river bottom. Chapter XI LIGNITE General Character The various grades of Brown coal which are found in the United States are known under the general name of Lignite. These are forms of coal which are intermediate in the trans- formation series between peat on the one hand and bituminous coal on the other. They contain a higher percentage of carbon and much less water than peat, but usually, less carbon and more moisture than bituminous coal. In color, Lignite varies from brown to a brilliant jet black, but the majority of our deposits are dull black changing to brownish black or brown on exposure. It breaks with a splintery to subeonchoidal fracture and normally has a specific gravity of 1.221. The water content is very variable in amount and it exists in the lignite both as combined moisture and as free water. Upon exposure most, if not all, of the latter may evaporate but the water in combination will not do so and even if the coal he heated and this moisture driven oif, its equivalent will be re-absorbed or recombined upon exposure to the air. Prior to the finding of oil at Spindletop in 1901 the mining of lignite was assuming considerable importance in Texas, but the advantages of oil in convenience of use and cheapness in price caused most, if not all, of the mines to be closed down for the time. As the supply of oil available for fuel uses has decreased and the price increased the use of lignite is again beginning to expand, and the time is near at hand when the disadvantages ac- companying t£e use of lignite will be more than offset by the economy which can be effected thereby and we may, therefore, look forward to a constantly growing demand for it. ' For fuller description see Dumble, E. T., Brown Coal and Lignite, Geol. Sur. Texas, 1892. 276 University of Texas Bulletin While not equal to bituminous coal in heating power it is nevertheless an excellent and acceptable fuel under proper con- ditions and will in time be one of the principal sources of supply for our entire Gulf Coast region. Methods of Utilization The principal use of lignite is, of course, for fuel purposes, and includes direct firing under boilers and furnaces, ■conversion into artificial fuel by briquetting to fit it for household and other uses, charring to produce a fuel between charcoal and coke, gas and by-products, and the manufacture of producer gas and eon- version into electric energy through gas engines. The details of these methods have been given more or less fully in the Report on Brown Coal and Lignite, the Bulletins of University of Texas Mineral Survey and the U. S. Geological Survey Report of Coal Tests at the St. Louis Exposition. In direct firing success can only be had by proper attention to the character of the fire-box, style of grate and draught arrange- ments. When these are properly designed for the character of fuel it can be burned very satisfactorily either with hand firing or mechanical stoking. Where the conditions are properly regu- lated the inconvenience and loss formerly caused by its property of slacking as it dried is practically done away with and the slack coal itself is a good fuel. Briquetting has also been attempted as a means of overcoming this disadvantage to its general use as a household fuel but ap- parently no great commercial success has as yet been attained in the manufacture. Up to the present the material used has been the raw lignites, from which most of the moisture has been evap- orated by heating, combined and compressed with various per- centages of coal tar pitch or asphaltum. A satisfactory fuel of this character demands considerable experimentation to find just what condition of dryness and percentage of pitch will yield, when pressed, a strongly coherent block of proper burning qualities. In place of simply drying the lignite it may be subjected to a charring process which provides for the recovery of the by- products consisting of gas, oils, and tar. The charred product The Geology of East Texas 277 briquetted with coal tar pitch forms an excellent fuel for all purposes. While no commercial installation of this character has been attempted here estimates, based on experimental runs which show the extent and value of the by-products, seem to indicate the entire practicability of such a scheme,^. These various methods have to do with the use of lignite by direct firing and it is probable that each of them will in time play its part in the utilization of this fuel. The demand for electric power at a reasonable price cannot be fully met by such method but it is entirely practical by the use of the gas from the charring process or through the manufacture of producer gas to secure a fuel for gas engines by means of which electric power can be generated at a minimum cost. Careful estimates indicate that at such plants erected in the immediate vicinity of the lignite mines electricity can be generated at a price to com- pare favorably with those plants in the west using water power, with the advantages, of a smaller investment in plant. Or it may be possible to pipe the gas to certain centers for such use: This in the writers opinion, will be one of the chief methods of lignite utilization in the future. As will have been seen from the various sections we have given conditions favorable for the deposition of Lignite occurred dur- ing nearly every stage of the Eocene, but, within the area map- ped, it was only during the Lignitic phase of the Wilcox and in the Tegua and Jackson that beds were laid down of sufBcient extent and purity to constitute valuable deposits. There are a few beds known in the Marine and it is possible that one or more of these may be of value locally, but extensive deposits such as are found in the beds below and above the Marine are not to be expected. LIGNITES OF THE WILCOX The deposits of Wilcox age include the lignite beds in Shelby and Nacogdoches Counties, these occurring in the comer of Free- stone, Limestone and Leon counties and in the northern part of Robertson county. The beds of lignite which occur in the vicinity of Center and • University of Texas Bulletin 307. Fuels used in Texas. 278 University of Texas Bulletin Timpson in Shelby county and extend southwestward to Garri- son, Nacogdoches county, are of considerable extent and of ex- cellent quality. A bed of good grade of lignite, 51/2 feet in thickness, outcrops along the beds of two creeks in the southern portion of the town of Center. An opening has been made on this bed at one place and two inclines sunk on the seam. The lignite is used locally for the production of electric power and for fuel in a cotton seed oil mill. It is reached in most of the shallow wells in the southern portion of the town, in which it forms the impervious layer above which surface water percolating down through the pervious sands accumulates in considerable quantity. There is a deeper coal seam underneath the town, but this lies somewhere between the depths of 300 and 570 feet, since a well 300 feet deep did not reach it but the 570 ft .well penetrated it although exact depth was not given. The two wells are only a few hundred yards apart, but abundant water was secured from a sand at 300 feet in the one, while the other, having substan- tially the same elevation, got no water above a depth of 570 feet. The water in the three deep wells here rises to within 80 or 100 ft. of the surface. Two exposures of the lignite were examined. The more north- erly shows from bottom upward; 1 Laminated gray sand. 2. Carbonaceous shale with thin streaks of lignite. 3. Solid bed of hard lustrous lignite, 5 ft. 4. Laminated sand. At the mine the dip in a S 70° B. direction is 2°. The roof and floor are both laminated sand, although a few inches of car- bonaceous shale directly underlies the coal. The thickness of the solid lignite is 5' 6". Small lenses of sand are found locally in the lignite bed. At the time of visit the mine was not in opera- tion and was flooded with water. The water and a poor roof makes mining difficult at this incline. It may be possible to find a better location by prospecting. At Timpson the lignite was successfully mined by the Timpson Coal Co. The mine was one and one-half miles south of Timpson The Geology of East Texas 279 and the lignite seam averaged a little over six feet in tMckness. The floor was a white clay while the roof was a hard black bituminous clay. South of Garrison about half a mile mines on opposite sides of the railroad were operated during the years 1900 and ]901. One of these was worked by the East Texas Coal Co., the other by the South Texas Coal Co. Each mine worked out about seven acres of ground. The shaft of the East Texas Coal Co. was 54 feet deep and the lignite seam averaged four and one-half feet in thickness. The roof was blue shale and very little water was en- countered. East of Timpson lignite is reported from several wells dug for water in seams four to six feet thick at depths varying from 55 to 70 feet. Six miles southeast of Timpson on the Attoyac a seam of lignite four to five feet in thickness is exposed. It is therefore evident that these seams of lignite are found pretty generally through an area twenty-five miles in length by six to twelve miles in width and even though they may not all belong •to one bed they are all of the same horizon and are similar in character. "We have the following analyses on these lignites : Ajttoyac Timpson Moisture 18.26 31.96 Volatile matter 43.51 39.53 Fixed carbon ^9.53 23.v)5 Ash 8.70 5.46 Total 100.00 100.00 Sulphur 2.46 1.46 The difference in moisture in the two analyses is due to the Attoyac samples having been partially air-dried. West of Garrison the beds of the Wilcox are overlain by those of the Claiborne until we reach the Trinity river. West of that stream the Wilcox again makes its appearance and beds of lig- nite may be looked for in it. They occur in good development north and west of Jewett. About eight miles north of Jewett there are two mines which are now in operation; The mine of the Houston Coal Co. at 280 University of Texas Bulletin ' Evansville has a spur from the Nelleva cut-off of the Houston & Texas Central E. E. while the mine of the Beargrass Coal Com- pany has a spur to the Taylor & Brazos Valley E. R. The Evansville mine has been in operation for several years and they are now working from the third shaft. The holdings comprise several thousand acres, most of which has been pro- spected with drilling machines. The mine is operated from a shaft 66 feet deep. The lignite seam is 12 feet thick with one parting at 7 feet. On account of the sandy nature of the forma- tions overlying the lignite, all of the lignite above the parting is left in the mine for a roof. Very little water is encountered in the mine. The coal is shot from place with black powder and shoveled into cars. The lignite as it comes from the mine is dumped from the cars and passes over grate bars which screen it into the lump, nut and slack grades. The capacity of the mine at the time of our examination was about ten cars per day. The Beargrass mine is about three miles north of the Evans- ville mine and is operated from a shaft 125 feet. The lignite is 9 ft. thick with a parting 2" to 4" thick, 5 to 6 feet from the bot- • tom. Another stratum of good lignite 7 feet thick is known to exist at a depth, of 350 feet. The holdings of the Company com- prise 1100 acres held in fee and 1200 acres under lease, with possibly 150 acres worked out. Some water is encountered in the mine. Similar coal is known at other places in the vicinity and there is every reason to believe that this will prove one of the best producing distracts of the Lignite belt. ANALYSES Beargrass Mine No. 1 Moisture 29.96 Volatile 41,68 Fixed Carbon 22.24 Ash 6.12 Sulphur ^ The lignite beds of Eobertson county extend from its eastern boundary entirely across it in a general southwesterly direction Beargrass Houston Co. Mine No. 2 Goal & Mfg. Co. 27.00 25.70 37.91 33.39 27.80 31.91 7.21 8.90 0.44 1.04 The Geology of East Texas 281 and underlie approximately the northern one-third- of the county. The northern boundary of the lignite beds is approxi- mately coincident with, but extends across the northern line of the county, and the southern limit of the field lies along a line extending from the Navasota river westward to OwensvUle, and then along the northern bank of Muddy creek to the Brazos river, near the mouth of Little river, in Milam county. This region embraces Tidwell, Beck, Heard, and Bald prairies, together with a series of other small prairies lying across the centre and throughout the northern portion of the county. Throughout the prairie regions the brown coals appear near the surface at various localities, and are exposed in several of the creeks and washouts traversing these regions. At Headville, on the C. C. Seal headright, the exposure is from four feet to six feet thick, and the deposit on "Wilson creek is about the same thickness. Many of the surface exposures, however, are thin and of no economic value. Thus the exposure on the Captain Orvis farm on the southwest corner of the George Robertson league, is not more than two feet of broken crumbly coal. Another out- crop of a similar nature occurs in a creek near the centre of the Joseph Fisher leauge. The coal at this locality is broken and crumbly at the south end, or toward the head of the creek, but as it extends northward it becomes dark brown in color and as- sumes a woody or peaty structure, having all the characteristic odor of the later material when freshly broken, and also con- tains numerous fragments of leaves. The heavier deposits of brown coal found throughout the prairie regions all lie at a depth cif forty-five feet and over. A number of borings on the southwest corner of Beck's prairie, on the Wm. FuUerton league, show section of: 1. From surface to first brown coal 46 to 55 ft. 2. Brown coal 4 to 4 % ft. I. Parting of sandy clay ■ • 10 to 12 ft. 4. Brown coal 7 ft. 5. Parting clay and sand 6 to 10 ft. 6. Brown coal 3 ft. Brown coal also occurs in the neighborhood of Owensville, where it is overlain by a red sandstone. This appears to be the 282 University of Texas Bulletin last exposure of the brown coal deposits oecurrmg in the south- ern portion of the county. At Heame this coal is found at 408 feet, while in the neighborhood of Wheelock, and at places be- tween this place and Franklin, wells, fifty to sixty feet fre- quently cuts brown coal. Throughout the valley of the Brazos and in the region lying between the two rivers, brown coal occurs in the well borings generally at a depth of thirty feet to four hundred feet. The exposure on the Brazos river west of Calvert is one of the best known of the entire region. This locality furnished the ma- terial for some of the earlier experiments in the use of lignite not only under boilers or for household purposes but also for the manufacture of briquettes. The earliest experiments of this char- acter were those of the writer who in 1881 made a shipment of this lignite to Havre where it was briquetted with coal tar pitch as a binder and a serviceable fuel secured. The cost of the pitch, however, and the fact that the air-dried lignite carried ten per cent of moisture (decreasing its heating power to that extent) acted as a bar to the further prosecution of the scheme. The success of the mines at Rockdale finally brought about the opening of these beds and a number of mines were started, some of which became regular producers and mined over con- siderable areas. While some mining was carried on in a small way previously the most active exploitation of the Calvert coal followed the pub- lication of the Report on Brown Coal and Lignite in 1892. The use of suitable grate bars increased its efficiency and later the application of the plans there suggested for locomotive firing to the engines of the Houston and Texas Central Railway made it possible for them to use it acceptably as a locomotive fuel. The records of company show that during a period of more than one year it was used in large quantities and at a considerable saving in cost over the Territory coal then available. With the coming of oil and cheapening of bituminous coal the use of lignite was discontinued and these mines ceased opera- tions. At the' time of our examination the Southwestern Fuel Co. was operating a mine four miles west of Calvert with a spur to International and Great Northern Railway. Two seams of The Geology of East Texas 283 lignite are worked from one shaft here, one being at 75 feet and one at 175 feet in depth. The upper stratum of lignite is 7% feet thick and the lower has a thickness of 12 feet. But little timber is used in the mine, a coal roof being carried. "Water is encountered in the mine in considerable amount, pumps being installed on both levels, the pumps on the lower seam handling about 30 gallons per minute and that on the upper seam handling over 200 gallons per minute. The lig- nite is shot from place with black powder. All lignite shipped is screened to about one inch in diameter. The capacity of the mine is 1000 tons per day. About 110 miners are employed. The . holdings of the company comprise 1200 acres, of which about 50 acres from the upper seam have been worked out. Analysis of Calvert coal: Southwestern Southwestern Calvert Bluff Fuel Co. Fuel Co. aid-dried Moisture 25.64 30.'60 16.45 Volatile Matter 35.55 30.19 40.24 Fixed Carbon 30.28 34.07 35.89 Ash 8.53 5.14 8.95 Total 100.00 100.00 100.00 Sulphur 0.96 0.86 1.17 The lignites of the Wilcox are represented west of the Brazos by the beds in the vicinity of Rockdale. LIGNITES OF THE YEGUA While no mining has been done on any of the lignites which occur in connection with the Yegua beds of the area mapped, there are a number of localities at which it is known to occur in beds of sufficient thickness for exploitation. In the vicinity of Huntington lignite is found in a number of shallow wells and in an excavation made at this town by the Texas & New Orleans Ry. for a water well a bed of lignite was encountered 25 feet below the surface which had a thick- ness of twelve feet. To the east of this on GiUand creek lig- nite outcrops which may be a continuation of the bed. Lignite was also found in wells drilled near Homer and 284 University of Texas Bulletin beds of four to seven feet in thickness occur 15 feet beneath the surface at Burke. In Brown Coal and Lignite two analyses are given of lig- nites from this belt. A brown coal of the variety pitch coal, from the Angelina river, sent in by E. G. Blount of San Augustine, is of distinctly lamellar structure, black in color, with pitchy lustre, without any traces of plant structure re- maining. It is hard, firm, does not soil the hands either on edge or face, and contains particles of jet-like blackness. The following is the proximate analysis: Moisture 12.15 Volatile matter 37.14 Fixed carbon 41.19 Ast 6.50 Sulphur 3.02 The Angelina county brown coal has the following compo- sition : ^ Water 12.40 Volatile matter 36.37 Fixed carbon 37.77 Asb 13.46 Sulphur Not determined In Houston county similar lignites are reported by Ken- nedy^ from Cochina bayou and westward to Big Piney creek and they are also known to occur at other localities between that creek and the Trinity river, in beds which are in places six feet in thickness. About three jniles north of Lovelady at Wootters Station on the International and Great Northern Railway is situated one of the mines of the Houston County Coal and Manufacturing Company. The same company is also operating the E'vans- ville mine 6 miles S. "W. of Jewett on the Houston and Texas Central Railroad. The main coal seam at Wootters has been prospected rather thoroughly and averages 5' 10" in thickness over some 5500 acres. The coal seam dips S 10 E at 2° in the workings and ' Geo. Sur. Tex., Third Ann. Rep. p. 34. The Geology of East Texas 285 it is worked from a two compartment shaft 58 feet deep by the Eoom and Pillar method of coal mining. In compliance with the state mining law there is an auxili- ary shaft situated 100' from the main shaft. It is a two com- partment shaft also, each compartment being 5'x6'. One of these is used as a runway and the other is an air shaft for ventilating the mine. For this purpose a 10' fan with curved blades is used, and a very perfect system of ventilation is maintained. The mine is, however, not troubled with gas. The main roof of the coal is a 3" seam of fine, grained, unctu- ous, stiff clay.,, This affords an excellent protection from water and only a minor amount of trouble comes from this source. Three sumps are provided, one of which is at the bottom of the main shaft. These are drained with pumps two of which are operated with gasoline engines and the other by a steam engine: The coal is usually picked out, very little shooting being necessary. The mine has been particularly free from acci- dents only one fatality being recorded in l;hirteen years of operations. Tho output of this mine averages about 300 cars per month during the summer and 350 ears per month during the wiliter, the cars having an average capacity of 60,000 lbs. each. The coal is used for power generating purposes and by packing companies, particularly in Houston. One mile north of Lovelady the same seam of coal as that worked at the mine is found at 120 feet. Overlying the main seam some 30 feet there is a thin seam of worthless coal. An analysis of the coal from the mine is given in the report of the U. S. Fuel Testing Laboratory at St. Louis in 1904. The coal has also been analyzed by Dr. Wm. B. Phillips, at the State Testing Laboratory. It is given below: Moisture 25.58 per cent. Proximate analysis, Dry Basis : Per cent. Volatile and combustible matter 52.90 Fixed carbon 33.00 Ash 13.11 100.00 286 University of Texas Bulletin Sulphur 0.80%. Ultimate analysis, Dry basis. Carbon 57.20 Hydrogen ^-'^^ Oxygen 21.67 Nitrogen 1-S*<> Sulphur 80 Ash lii.ll 100.00 Heating power, dry B. T. U. 10,120. Kennedy describes the outcrops on the Trinity as follows : The southwestern lignite field is best developed at Hydes' and Westmoreland bluffs, on the Trinity river. At Hydes' bluff the outcrop extends from near the ferry nearly half a mile in a southeasterly direction. The section of bluff shows: 1. Yellow sandy loam changing into an ashy gray on top, where cultivated 8 tt. 2. Conglomerate of ferruginous and siliceous pehbles, broken 'pieces of nodular iron ore, ferruginated and silicifled wood and brown, sand 2 ft. 3. Dark blue sandy clay, having one foot of laminated brown sandy clay on top, in contact with the conglomerate the dark blue clay containing more or less of iron pyrites. . . .10 ft. 4. Soft lignite very friable and mixed with sand, in deposition very irregular, and extending from two inches to 2 ft 5. Light gray sandy clay, the clay becoming more prevalent towards the base of the bed 10 ft. 6. Lignite 2 to 6 ft. 7. Dark purple clay , -IVz ft. 8. Gray sand, containing nodules of sandstone 4 ft. The lower bed of lignite at this place is very pronounced, and forms a ledge in some places six feet wide along the face of the bluff. In texture, it is strong and solid, of a dark glossy luster when first mined, which it retains for some time, but ultimately becomes a dead black, with pitchy streaks. No woody structure visible, Compact uneven to even fracture, shrinkage cracks parallel with and perpendicular to plane of bedding. This bed averages four feet thick, is from six to fifteen feet The Geology of East Texas 287 above low water level, and is easy of access. It breaks in large cuboidal blocks, and disintegrates slowly when exposed to the air. Its composition is very variable, changing mate- rially at different portions of the bed. One analysis given shows it to have 16.70 per cent of ash, but another determina- tion of a specimen not many yards distant showed only 7 per cent of ash. It is probable that the brown coal from this deposit may, with the good facilities for transportation at hand, be utilized. ANALYSIS Moisture 11.80 Volatile matter 36.06 Fixed oarljon 32.56 Sulphur .88 AsbL 16.70 There are in Madison county extensive beds of lignite coal but the thickness seems to vary considerably locally and hence no attempt will be made here to indicate workable deposits. The outcrops of coal noted which would stand prospecting with bore holes are given below: In western Madison county on the James M. Harbor survey along Shepard's creek, on the farm of Mr. Nash, there is ex- posed 21/^ feet to 4 feet of black lignite of light weight and only fair grade as it tends to break out in a shaly manner. It is overlain by 3 feet of laminated chocolate colored, sandy, shaly clays and underlain by 2i/2 feet of lignitiferous to highly carbonaceous brown to black sandy clays. This outcrop caught fire a few years ago and burned for a long time. It became so troublesome that Mr. Nash was compelled to haul water to extinguish the fire. Lignite coal is found outcropping both below and above the above mentioned locality along Shepherd's creek. On Cottonwood Prairie in the northwest corner of the Amy Boatwright League on the place of Mr. John McMahon in digging a well 10 feet of lignite coal was encountered at 20 feet. This coal is black and lustrous and seemingly of a very good grade. No data could be obtained as to what overlay the coal. 288 University of Texas Bulletin Two miles north of the above place on the farm of Mr. Y7ill Fannin in the northwest corner of the Simon Jones league in digging a well Mr. Fannin encountered 20 feet of lignite coal at 40 foot depth. He claims that this coal was black and lus- trous and was used by the local blacksmiths for forging. Lig- nite coal outcrops along Iron Creek, south of Mr. Fannin's house, but nothing over 3 feet thick could be found. This de- posit would warrant careful prospecting. On the Wm.- Curry Survey on Larrison creek there is found outcropping along the creek 2'-3' of a fair grade of lignite. The Yegua beds occur only in a limited area in Grimes county and we know of no lignite in them. In Brazos county seams of lignite are found at many places at depths ranging from 30 to 60 feet. The brown coal deposits are usually found in digging wells, and no reliable information can be obtained regarding their quality or thickness. In the northwestern part of the county a deposit crops out in the bank of the Brazos river near Nebelt or Black shoals. It stretches across the river into Burleson <30unty, and on the Brazos county side has a thickness of from 12 to 14 feet, as shown ia the following section: 1. Bluff loam or river deposits 6 ft. 2. Brown clay 3 ft. 3. Yellow sand, with gravel near bottom 10 ft. 4. Brown coal, shaley near top, but becoming compact at base of bed 12 to 14 It. 5. Lignite sand An analysis of the brown coal in this bed made by Dr. W. H. Melville, chemist of the Geological Survey, shows it to have the following composition:. Moisture 18.33 per ceijt Volatile matter • • 52.62 per cent Fixed carbon 24.88 per cent Ash 4.17 per cent 100.00 Sulphur 87 per cent Of the Brazos river brown coals of Tegua age this deposit The Geology of East Texas 289 can probably be utilized the most economically. The coal can be readily obtained by stripping, and the transportation facil- ities are exceptionally good. The Hearne and Brazos Valley Railway passes within two miles, and the level tract of country between the river and the railway line would greatly facilitate the construction of a siding or branch to the mine, which might be built at the minimum cost allowed for this grade of work. LIGNITES OF THE JACKSON Lignite in the Jackson is known from White Eock creek in western Trinity county, near Potomac in northern Polk county, and on Cameron creek in southern San Augustine county. Beds of lignite have been found in wells at Groveton; Trinity county. The exposures on White Rock creek, Trinity county, are situ- ated 1% miles north of the Missouri, Kansas and Texas Rail- road bridge over that creek. It is reported that the lignite bed is 6 or 8 feet thick at a minimtim with its base not seen. The bed is in the bottom of the creek. On the eastern portion of the Jacobs League about ^ mile north of Potomac and about 250 yards Avest of the Houston Bast and West Texas Railroad 31/2 feet of lignite is overlain and underlain by brown carbonaceous shale. Near the southwest corner of the Nathaniel Hyden League in southern San Augustine county a thin seam of lignite varying from 8 inches to 2 feet is over- lain and underlain by soft clay. In the Groveton wells nine feet of lignite was found at 52 feet, seven feet at 81 feet, four feet at 101 feet, and seventeen feet at from 337 to 354 feet. The Groveton Light and Ice Company's well at Groveton found beds of lignite as follows: Two feet of lignite at 73 feet, twenty-two feet of shale and lignite at 98 feet, and ten feet of lignite at 120 feet. Other localities in Trinity county where lignite was reported but not examined are: (1) about the middle of the north line of the M. B. Mancha League, where there is said to be also an oil seepage. (2) One half mile southeast of Cochino bayou on the J. Bethea grant on the north line of the county, and (3) near the southwest line of the James Hanley League. A lignite bed, 5 feet in thickness, outcrops in the bed and 290 University of Texas Bulletin the lower portion of the west bank of the Angelina river ort the Aaron Ashley Survey, 15 miles east of Zavalla, Angelina county, and is visible only at low water stage. At the time of low water, when the prospect was examined, the lower 2% feet was submerged. Extreme low water would cover only the lower foot or foot and a half. The lignite is of a fair quality and breaks in large hard blocks. Samples were secured from the entire five feet of thickness and the entire bed appeared from the physical ex- amination to be fairly uniform in quality. The top of the bed, which is exposed for some 200 yards along the channel of the river, was characteristically checked by weathering, the sur- face exhibiting a thin whitish effloresence irregular in extent and thickness, but never thicker than a thin film. The weath- ered coal is in fresh, bright, and hard condition. The coal bed is directly underlain by 3 inches of brownish carbonaceous clay which is itself underlain by at least 6 inches, with total thickness unknown, of a blue clay. The clay is entirely submerged at extreme low water. All known expos- ures of the coal are in the alluvial bottom lands of the river. Therefore, the exposure may only represent a local isolated outlier forming an island-like mass flanked on all sides by river alluvium. There is, of course, the possibility that a workable deposit may be found underlying the higher lands west of the river bottoms. Unfortunately, no wells have been put down on these higher lands which would serve to prove or disprove the presence of workable coal. The exposure visited is distant some & miles from Turpen- tine, the. terminus of a railroad (The Burrs Ferry, Browndel and Chester Railroad) connecting with the Texas and New Orleans Railroad at Rockland. It is also distant about five miles from the St. Louis, Southwestern Railway at Monterey. The coal outcrop could be reached by a spur down the river bottom from either of these railroads. Lignites are also found along Chalk creek in northern Walker county. On Kelso creek near the middle of the S. Young Survey about on the line between Walker and Grimes counties there The Geology of East Texas 291 is a hill where the Brooks Brothers prospected for lignite. In this hole at present one can see only about 8' of rather soft medrim grained, gray sandstone, the rest of the hole%eing filled with sand. Immediately underneath the sandstone, ac- cording to Mr. Thomas J. Brooks, there occurs 10' of excellent lignite with a black color and lustrous appearance. A short ways down the creek another hole was dug and here only 4% feet of lignite was encountered. In Grimes county thin seams of brown coal occur in the neighborhood of Kellum Springs, and stretch across the county in a northeasterly direction as far as the Bedias postofSce, near the northeastern corner of the county. A seven foot deposit of brown coal also occurs in Tanyard creek, on the Boatright head- right, near Piedmont Springs. This coal as exposed is of the brown grade throughout the upper three feet and is mixed with a brown clay, while the lower four feet, of blacker coaL is too much mixed with a black sand to be of any economic value. In the record of a boring at Lamb Spring, fifteen miles north of Navasota, brown coal has been reported at various depths and having various thicknesses. Koughly, the section of this well shows : 1. Brown coal, first seam at 12 feet 2 ft. 2 Brown coal, second seam at 34 feet 2% ft. 3. Brown coal, third seam at 38 feet 2 ft. 4. Brown coal, fourth seam at 41 feet 7 ft. 5. Brown coal, fifth seam at 52 feet 10 ft. Several deposits of brown coal are reported as occurring deeper in the boring, but all are accompanied by water. A small deposit of coal also occurs in the bank of the Navasota near Sul- phur Springs. The lignites of the Jackson have not been mined to any extent nor have we many analyses of them. It is probable that in the region west of the Trinity- Angelina divide in which volcanic ash is so abundant that some, if not all, of these lignites will show considerable ash. Chapter XII PETROLEUM AND NATURAL GAS Origin Two widely divergent theories have been advanced in regard to the origin of petroleum and natural gas. One of these refers these substances to inorganic sources, that is, makes them the result of chemical action with mineral matter as a base. This theory is supported by the fact that hydrocar- bons of this character are found in certain meteorites and in vol- canic emanations. Its supporters also claim the presence of igneous rocks in certain fields as further evidence in its favor. We have no real evidence however to show that any oil field of importance has derived its oil from such a source, consequently, while there is no question that oil may be formed in this man- ner, the majority of geologists of the present day seem to be substantially agreed that the greater part, at least, of oil and gas in place of being of inorganic origin is derived from the re- mains of plant and animal life and therefore of organic origin. Apparently the first step in such formation of petroleum is the separation and segregation of the fatty materials of the remains of plants and animals by the action of bacteria and it is from the fatty matters thus produced that petroleum and natural gas are derived by natural processes of partial decomposition, distill- ation, rendering or refining. The transformation of this fatty material into petroleum and gas is ascribed by many, if not most, geologists to some form of temperature or pressure distillation, or some poeess of fermen- tion, (geodynamic or geoehemic agencies) acting on these ma- terials after they have been entombed in the rocks. That is, that the animal or vegetable matter, either as debris or altered into fatty matters such as resins, waxes or adipocere, is embedded in the sediments at the time of their deposition and later converted into petroleum or gas through some of the various methods in- cluded under the general statements above. On the other hand there are those who believe that this trans- The Geology of East Texas 293 formation takes place before deposition. This would necessitate the decomposition of the organic bodies "elsewhere than in the strata themselves and yet in such a place that the oil would be retained and collected until it was liberated upon the surface of rivers which were depositing the sediment"^. We have here in contradistinction to the prevalent theory that the transformation of the fatty materials derived from organic remains into petroleum takes place after the burial of these ma- terials in the sedimentary rocks, through the action on them of pressure distillation, or by some geo-chemic process, one which postulates the formation of petroleum from similar material, by natural processes, at the surface of the earth, without the inter- position of geo-dynamic agencies, and its contemporaneous depo- sition as petroleum with those sediments with which it is origi- nally connected. The actual formation of petroleum and other bitumens at the surface of the earth in such relation to other sediments as might permit their deposition in the manner claimed for them seems to be fairly well established by observations in various parts of the world. Among the localities described may be mentioned the small bays of the Red Sea, the region of the Dead Sea, the Mediterra- nean between Cypress and Syria, the Gulf of Suez, sea marshes in Sardinia and Sweden and numerous peat-ibogs. The actual formation of petroleum and other bitumens in peat-bogs, at the bottoms of bays, along the margin of the sea and even on the sea-floor, would appear to be as well established as any of the facts upon which the pressure-distillation theory is based. The association of such petroleum with sediments in course of formation, and the readiness with which surface petroleum is carried down and deposited by muddy waters are facts in favor of contemporaneous deposition, which is further sustained by many field observations which seemingly admit of no other ex- planation. This is especially true of the coastal fields of Texas and Louisiana. ' Murray Stuart, Geological Survey Imdia, Vol. XI, p. 239. 294 University of Texas Bulletin OCCUERENCE The presence of oil and gas was recognized in East Texas many years before the drill made it available. Seeps of oil and beds of asphalt were known at Sour Lake, Saratoga and else- where. Gas springs, sulphur waters and mud volcanoes, all of which are evidences of oil and gas, were known, but no one sus- pected the vast stores which have been brought to light. Small wells were found near Nacogdoches, at Sour Lake and Saratoga during the fifteen years preceeding, but the real birth of the oil industry in the Coastal Area of Texas, was the bring- ing in of the Lucas well at Spindletop, three miles south of Beau- mont in January 1901. It has been said of this well that probably no other event in the development of the petroleum in- dustry in the United States caused such a profound sensation, reaching all of the interests concerned with the production and sale of this article, as the unexpected outburst of this well and not until it was found that the petroleum produced by this gusher was 22° Beaume and contained a large proportion of sul- phur (thus decreasing its value for refining purposes under proc- esses then in use) was confidence restored to the producers in the Eastern petroleum fields. The bringing in of the well was followed by the drilling of many wells in the Coast country, and from these we have learned something of the location and nature of the deposits, although there is much that is not yet clear. As the gusher oil was originally found in connection with the domes at Spindletop, Sour Lake, Humble, etc., it was at first believed that all domes might prove to be oil domes. This was soon found to be a mistaken idea, but even today it is not possi- ble to say, in advance of drilling, whether a given dome will or will not prove an oil producer. We do know, however, that oil is not confined to the domes proper but may occur where no doming is apparent at the surface, provided the underground structure is favorable. In the Coastal Area of East Texas oil occurs at several hori- zons beginning with the Cretaceous. The active deposition of Cretaceous oil began with the Wood- bine series. The Geology of East Texas 295 From Woodbine the outcrop of the formation stretches east- ward into Louisiana, where it is known as the Bingen sand, and in the Caddo region the sands are highly petroliferous and fur- nish the best wells of that belt. The productive oil and gas of the Eagle Ford is confined to the "Blossom sand", which is un- known as such on the Colorado. Gas is plentiful in the Blossom sand in the Caddo field, but such oil as is found there is heavy, and producing wells are rare if not unknown. The bituminous and even petroliferous character of the shale is apparent, how- ever, at many places along its outcrop in central Texas, and it furnishes seepages of a heavy tarry oil from small wells near Waters Park, north of Austin. The Annona chalk, which is the eastern representative of a portion of the upper Austin or basal Taylor, is a good oil hori- zon, and the Nacatoch sand, probably the equivalent of part of the Taylor, is an excellent gas horizon. Thus, in Louisiana, there are four distinct horizons of gas and oil in the Upper Cretaceous, the principal of which is the Woodbine, or Bingen, as it is locally known, and it is probable that the oil and gas in these beds are largely indigenous. The deposits of commercial value occur in coimection with folds and domes, and at present are best developed in the area between Red River and the Sabine, but may extend to the west of the latter. The other occurrences of Cretaceous oil west ofthe Sabine river are confined to the Taylor beds. The pools at Powell, Cor- sicana, San Antonio, Thrall and other localities find their supply in these beds. In some of these the oil is possibly indigenous, but at Thrall it is probably migratory. The deposits of Eocene age, in spite of their wide areal distri- bution in the Gulf Coastal Plain of Texas and Louisiana, have yielded comparatively small amounts of petroleum. No oil whatever is known in the Midway or Wilcox of the Lower Eocene and only a few small pools have been found in the Marine beds which overlie them. In Nacogdoches county small bodies of oil were found, and another smaU amount of similar oil was found in these beds at Crowther in McMuUen county, some 300 miles southwest of the first. While oil indi- 296 University of Texas Bulletin cations may occur at other points, no workable deposits are known. The Tegua sub-stage of the Claiborne, however, has proved to be a very valuable gas horizon in the region between the Sabine and the Eio Grande, and it may be that it will equal in productiveness some of the sands of the Cretaceous, or even those of the Carboniferous, when it shall have been properly exploited. Beds of the Jackson and Oligocene, which followed these, are equally destitute of oil. The probabilities are, therefore, that while the conditions were favorable for the formation and deposition of vast quan- tities of lignites and an abundance of other organic matter during the Eocene, the conditions for the formation or storage of petroleum were comparatively unfavorable. The Tertiary oil of the Gulf Coast proper all occurs in sedi- ments of Neocene age, often in or around domes, and fre- quently in connection with deposits of salt, gypsum and sul- phur. While the shore deposits of the Fleming beds are non-bitu- minous and no sign of either oil or gas has ever been found in them, the seaward extensions are bituminous to a consider- able degree. Small pieces of lignite and asphaltic material have been reported from a widely extended series of wells. Shows of oil appear in these beds at various horizons and good wells have been obtained in them. Wells in the Sara- toga field drilled to a depth of over 2,200 feet obtained their supplies from sandy shales belonging to this series. The Lafayette, which closes the Pliocene in the area, shows in some wells a thickness of 500 feet of sands, gumbos, and clays. They carry water in abundance, but no oil. Of the overlying Pleistocene deposits the Beaumont clay, of Port Hudson age, is most characteristic. These clays and sands are very variable in thickness. In places the Pliocene beds are found in low hills, surrounded but not covered by the clays, while in others the Beaumont clays show a thick- ness of 2,500 ft. and more, above these beds. The probabilities are, as stated, that all the oil of the Louisi- ana and Texas coastal belt is of Neocene age. It is separable The Geology of East Texas 297 into two classes, shale oil and dome oil. The first is regarded as indigenous to the beds in which it is found, and the second as migratory oil derived from it. The relations of these two classes of oil are particularly well shown in the Humble field. The dome oil was first discovered, and the field brought in, in 1904. The wells were comparatively shallow, being usually less than 1,400 feet and the oil, like that of the other dome fields, was of 20 to 24 gravity Beaume. The plug of under- lying salt was found at 1,400 to 1,600 ft. over an extenSive area. As the production of this central pool declined, wells were sunk at various distances from it; and the B'sperson wells, a mile south of the dome, found a pool of light oil in shales. Later, similar oil was found in shales north of the oil field, and more recently large producers were secured in the shales from 1 to 2 miles east. This oil has a gravity of over 30° Beaume. The series of beds in which the oil is found here consists of shale and gumbo with some sand and dips away from the dome on all sides. Between the producing area on the dome and that of the shale oil belts on its flanks, there is a strip half a mile or more in width in which oil is not found in any quantity and in this belt the beds are apparently mucTi broken. The conditions indicate that a mass of salt and gypsum has come up through the sedimentary beds which are broken and tilted. This condition is repeated in other domes whether oil is present or absent, and it is probable that the origin and original distribution of the oil was entirely independent of the domes or dome material. The oil was formed in the usual manner and deposited in beds of Neocene age. The movements which gave rise to the domes permitted and facilitated the collection and concentration of this oil into pools. When the uplift which caused one of the domes was close to one of these pools it captured a part or all of its oil which naturally gravitated to the highest point possible. Where oil pools were absent the domes are not oil bearing. 20-BT. 298 University of Texas Bulletin CRETACEOUS OIL AND GAS One of the first really productive oil fields of the State was that at Corsieana which found its oil in the Taylor marls. When the writer examined the field in May, 1897, there were six small flowing wells which got their oil at 1040 to 1050 feet. Later the field had a wider development and a second field was brought in to the eastward known as the Powell field. This seemed to occupy the crest of a gentle fold with general northeast-southwest strike. While there is a possi- bility of other similar folds occurring between this and the line of Cretaceous islands none have yet been found. Gas and oil are found at Mexia and Wortham in the Taylor marls of the Upper Cretaceous. The horizon is substantially the same as that of the oil and gas at Corsieana and the oil at Powell. The Mexia field is situated in the northwestern portion of Limestone county. Most of the wells are located within the radius of a mile of the town of Mexia, mostly west and north- west, north and northeast of that town, but others have been put down to the south and between Mexia and Wortham on the north.. The elevation of Mexia is approximately 530 feet. The wells have depths ranging from 670 feet to 1500 feet. The Wortham wells are mostly within the town of that name, which is situated on the Houston & Texas Central Rail- road in the extreme northwestern corner of Freestone county. Wortham has an elevation of approximately 475 feet. The wells have depths ranging between 1000 feet and 1200 feet. Well No. 1 of the Mexia Oil & Gas Company tested 14,550,- 000 cubic ft. of gas per 24 hours, with a rock pressure of 275 pounds per square inch. The gas is entirely dry. It had the comparatively high fuel value of 965 B. t. u. Well No. 3 of the Mexia Oil & Gas Company had a rock pressure of 220 pounds per square inch and produced half to three-quarters of a million cubic feet per day after being allowed to run for some months. At Wortham the gas emits a strong odor. The first notable well came- in during the latter part of May, 1912. The pres- sure appeared to be about 200 pounds and the production The. Geology of East Texas 299 about two and a half million cubic feet per day. The well sprayed black oil claimed to be 28 degrees Beaume gravity. It rapidly went to salt water, claimed to give ofE an odor of ammonia. Throughout the area eastward of these occurrences the beds of the Cretaceous are buried beneath the Tertiary sediments, so we cannot know the exact relations. On the western border of the Sabine pmbavment the Creta- ceous was uplifted and folded prior to the deposition of the Ter- tiary and similar uplifting occurred on the eastern margin. We have, as yet, found no evidence of such folding between the Cre- taceous islands and the Sabine peninsula. Any folding of the in- terior area at a later date would have involved Tertiary beds and would probably be evidenced by surface conditions. Since the Tertiary of this region §hows few structures of this kind, it is probable that such movements were either rare or of lim- ited extent. The occurrence of Cretaceous oil in commercial quantities in this area could only be expected in connection with such structure, and therefore the chances for productive pools from beds of this age within this Sabine basin seem few. The only occurrences of Cretaceous beds known in this area are those of the Cretaceous islands in Anderson and Freestone counties and along the western border of the Sabine Peninsula in Panola and Shelby .counties, and as yet no commercial pro- duction of oil has been secured from them. The Butler dome in southeastern Freestone county covers an area of about four square miles and the differences in elevation between the lowest and highest points are more than 100 feet. While it has not been studied as carefully as some of the better known localities it has been proven to be one of the chain of Cretaceous islands and the materials exposed are said to include beds from the Woodbine to the Taylor. No drilling has been done to test the oil conditions. The Palestine dome^ is located six miles west of Palestine. Here we find a depression of irregular shape, with a maximum diameter not exceeding three quarters of a mile. The bottom ■U. S. G. S. Bull. 661, p. 253. 300 University of Texas Bulletin of the depression is occupied by a shallow lake with its surface fifty feet below the general level. The banks on the eastern and northern sides slope upward gradually, but that on the west is more abrupt. The lowest rock exposed is a sandstone, which, as proved by its fossils, is of Woodbine age. Between this and the under- lying body of salt, 140 feet below, there is 85 feet of gray to yellow water sand, 40 feet of dark gray sandy clay, under which there is in places a eaprock of hard limestone of vary- ing thickness. Apparently, therefore, the Woodbine rests di- rectly upon the salt mass. The Woodbine, at its exposure, shows a dip of 46 degrees to the northwest. It is overlain by the Eagle Ford, Austin, Taylor (?) and Navarro beds, all of which dip northwest at angles varying from 40 to 50 degrees. No beds were found which can he referred either to the Midway or the Lower Wilcox, the lowest Tertiary beds being sands, clays and lig- nites belonging to the Middle or Upper Wilcox. According to Hopkins, these Wilcox beds in the vicinity of the dome show southeast dips of 38 to 57 degrees, which decrease within a mile and a half to 20 or 30 degrees, and within three miles become normal. On the_ northeast and southeast the Clai- borne beds reach within 3 to 5 miles of the dome, but show little, if any, change from normal dip. Six miles northeast of this locality, the Keechi dome shows the Austin Chalk at the surface, surrounded by the Navarro beds, and these are in turn encircled' by the Wilcox, which dips away from the dome at angles varying between 20 and 30 degrees (Hopkins). As in the case of the Palestine dome, the Claiborne is 3 to 4 miles northeast of the Keechi dome. The thickness of the beds as interpreted from logs of the wells would be approximately 500 feet for the Navarro and Taylor, 800 feet for the Austin and Eagle Ford, and 400 feet for the Woodbine. The salt mass reached at 2200 feet was drilled into for 900 feet, a 30 foot bed of water sand being encountered in it at a depth of 2900 feet. Hopkins summarizes the possibilities of oil and gas in the Palestine dome as follows: "The highly folded, faulted, and eroded condition of the The Geology of East Texas 301 Palestine dome and the general absence of oil and gas as sur- face seepages and in shallow wells in this area detract from its oil prospects. The tilting and faulting of the rocks prob- aljly provided outlets for the escape of oil, and as no evidence of oil exists the conclusion is suggested that no large amount remains here, even if it ever accumulated. It is possible, how- ever, that the soft and dominantly impervious nature of the formations involved in this fold closed up any possible lines ■^f escape for the oil, as its absence at the surface may be in- terpreted to indicate. The eroded condition of the dome, as shown by the presence of Cretaceous rocks at the surface, and the presence of the salt core within 140 feet of the surface over a large area are also unfavorable conditions, as they eliminate the possibility that oil may be found on the crest of the dome, which might otherwise be the most favorable for its occurrence. Oil in commercial quantities has not yet been found in a salt dome so far removed from the coast as this one. "The most likely area for the occurrence of oil, if it is pres- ent in this dome, is within a belt about half a mile wide that surrounds the area in which salt approaches within a few hundred feet of the surface. The most favorable part of this belt is probably near its inner margin, where the underlying formations may be tilted up against the salt mass and prob- ably end against it. "So far as observed, there are no subsidiary folds on the flank of the domes that would serve to trap upward-migrating oil; if such a trap exists it is at a considerable distance from the dome or is produced by the pinching out of a porous bed or by a fault." The Keechie dome has been prospected to some extent. The Producers Oil Co. Barrett & Grenwood well No. 1 is ou the southern slope of the dome, near the contact of the Wilcox and Navarro formations. It is reported to have reached the Austin chalk at &86 feet and the top of the Woodbine (?j sand at 1,686 feet; it penetrated rock salt from 2,200 to 2,900 feet, water-bearing sand from 2,900 to 2,930 feet, and rock salt from 2,930 to 3,130 feet, at which depth it was abandoned. The Woodbine ( ?) sand yielded 1 or 2 barrels of heavy tarry oil at 1,686 feet. A second well was drilled on the same lease, 302 University of Texas Bulletin 1,000 feet east of south of the first. The Austin chalk is re- ported in this well at about 1,400 feet, and the Woodbine (?) sand, which yielded salt water that could not be bailed below 500 feet, at 2,297 feet. The dip from the first to the second well, as indicated by the Woodbine sand, is about 35'. The possibility of finding oil in this dome is considered better than in the Palestine dome because it appears to be less faulted, the salt core does not come so close to the surface, and the Woodbine (?) sand is within reach of the drill and also deeply enough buried to have retained its oil^. While the Navarro and Taylor do not appear to be oil- bearing at either the Palestine or Keechie domes, there may be some place along the general" line of uplift where more favorable conditions exist. Wells drilled along the western border of the Sabine Plateau from Carthage to Sabinetown have found Cretaceous beds at various depths with both oil and gas. In June, 1916, the Palmetto Petroleum Company, drilling a well on the Trosper farm in the northeastern corner of Panola county, had a blow-out from a sand found at 1050 feet. The flow was estimated at ten million cubic feet of gas and four thousand barrels of water daily. The gas not only came up from the well, but broke out at five different points, one of them a thousand feet away from the well. On June 25 th it was estimated that at least 25,000,000 cubic feet of gas was escaping from the six vents. A number of wells have been drilled in the vicinity, and the chalk has been found at depths varying from 1600 to 1800 feet. Apparently this is near the western border of the Sabine Penin- sula, and it is entirely possible that oil may be found here in commercial quantities. Another locality at which Cretaceous oil has been found is at Flat Fork between Center and Tenaha in Shelby county This is south of the Panola locality and like it, is apparently near the western border of the Sabine Peninsula. The surface formation belongs to the Lignitic phase of the Wilcox and in one of the wells drilled here this formation has a thickness of 840 feet and > Hopkins, U. S. Geol. Sur. Bull. 661, pp. 267.8. The Geology of East Texas 303 carries some light showings of oil and gas. The underlying Mid- way is only 140 feet in thickness and overlies the Cretaceous at 980 feet. The Annona chalk was found at 1690 feet and oil was found at 2020 feet. Kennedy reported that properly handled this well might be deyeloped into a producer giving 25 to 50 bar- rels per day, but that it should be deepened to the "Woodbine sands which he estimated would be found at about 2400 feet. In the vicinity of Sabinetown several wells have been drilled into the Cretaceous. One mile west of town, the Sabine Ore & Mineral Company drilled a 1500 ft. hole in which the top of the Wilcox was struck at 80 feet and showed a thickness of 980 feet. It was underlain by 200 feet of Midway beds and the top of the Cretaceus (Arka- delpha shales?) was reached at 1265 feet. Some showings of oil and gas were found in these wells. A well drilled on the Jesse Low Survey four miles south of Sabinetown is reported to have reached the Annona chalk at 1900 ft. This well showed gas at 1100, 1500, 1900 and 2300 feet, and the gas burned for over two years. The total depth of the well was 2332 ft. Ten miles south of this locality a well was drilled on Housing bayou. The log shows: 580 feet of Tegua materials underlain by over 700 feet of Cook's Mountain with the Wilcox forming the bottom hole from 1315 to 1749 ft. If the Wilcox maintains the same thickness here as in the well west of Sabinetown, 12 miles north, the top of the Cretaceous would be found at 2330 feet, or nearly 1000 feet deeper than in that well. EOCENE OIL AND GAS A number of wells drilled into or through the Wilcox and Mid- way^ formations, in different parts of this area, have furnished small showings of oil and gas and an occasional seep of oil occurs in them at the surface, but no productive wells have, yet been found in either formation, and it is not thought probable that there will be. In the Claiborne, however, the conditions are more favorable. The Marine beds have been found to be petroliferous in several localities, and while the fields are small, they may be worked with satisfactory results if properly handled. 304 University of Texas Bulletin The Erst field to be developed in the Marine was that south of Nacogdoches, known as Oil City^, where operations began in 1877. The oil is found in shallow wells, practically all of them being less than 400 feet in depth, and the deposits occur near the mid- dle of the Cook Mountain beds. The oil sands are seemingly in small pockets and are irregularly distributed through the bed«. Seepages of similar oil occur in the valley of Bast creek two miles north of Oil City. A number of wells have been drilled at Chireno, one of which produced a few barrels of oil from a depth of only 14 feet. Some of the wells in this locality were drilled to a depth of 1600 feet but such oil as is found usually lies near the base of the Cook Mountain beds and like the Oil City deposits occurs in small pockets. A well two miles south of Chireno reported a small amount of oil from what are believed to be Wilcox beds. The oil of this region has a gravity of 23 degrees Beaume and although used as a fuel oil has excellent lubricating qual- ities. Near Enal, a station on the Texas and New Orleans Rail- road 40 miles south of Oil City, a well was drilled in search of oil. The generalized section of it shows 255 feet of sands, shales, lignites and gumbo of the Jackson underlain by 500 feet of Tegua clays and sands. Beginning at 765 feet the fossiliferous beds of the Cook Mountain horizon were reached and drilled into for over 500 feet. Small amounts of oil were found at 767, 1205, and 1265 feet, but no production was secured. Oil seepages occur in the Marine beds both northeast and east of Palestine and the asphaltic sands resulting from them were utilized at one time as street paving material at Pales- tine and elsewhere. Quite a number of wells were drilled in this region, one of them as deep as 2500 feet. Oil was reported in small quantities at 864 and 1010 feet. Southwest of Palestine, between Tucker and Oakwoods and south of the salt mine small seeps of heavy asphaltic oil have ' Second Ann. Rep. Geol. Sur. Tex., p. 271, etc. Univ. Tex. Min. Sur. Bui. 1, p. 1, etc. The Geology of East Texas 305 been found in water wells. These wells are in the Upper Wil- cox and presumably the oil is indigenous^. In northern Madison county several wells have been drilled for oil and' small shows were found at 300 to 400 feet. The indications are that deposits may exist here similar to those of Nacogdoches county. Other occurrences of oil or gas might be enumerated from these beds but they are all of the same character and while they may be locally valuable, can only be of limited extent. While the Yegua formation supplies the largest and most productive gas fields of the Texas Tertiary, there is at present no production within the area under consideration and we have but little information regarding prospective production in it. West of the Colorado heavy gas is found in wells drilled into the Yegua and the gas fields at Aguilares east of Laredo find their supply in these beds. Evidence of its former presence in Grimes county is found at several localities in fused and metamorphosed shales and clays which evidently owe their present condition to the heat of burning gases escaping through fault fissures. The possibilities of the Yegua in this region as a gas field are well worth investigation. No commercial deposits of oil or gas have been found in the Jackson although like the Marine it apparently carries both in small quantities at a number, of places. A well drilled in Grahams creek in eastern Angelina county found a little oil in the Jackson beds at 17 to 42 feet. A small amount of oil is still flowing from this well. Similar shows of oil are found in other wells drilled south of these. Along Pine creek southeast of Bedias in Grimes county small boulders of grahamite are found in the Jackson beds bordering the creek. At Weisers bluff on the Trinity a mass was found in the Jackson eight to ten feet in length and four feet in thickness. Similar material was found on surface at ' A possibility exists that the oil is of Cretaceous origin and has reached its present location through breaks in the shales overlying the salt beds. 306 University of Tsxas Bulletin well drilled in Little survey near Black creek in northeast Walker county. Three wells were drilled here. The first was between 1500 and 1600 feet deep. The second well blew out at 900 feet, the gas burning for several days. A small amount of oil came up with the gas. In the third well gas and hot water were found at 1800 feet. The gas from this well burns continuously when lighted. This oil and gas comes from the Claiborne and Lignitic. No oil or gas deposits are known in the beds of the OHgo- ene or in that part of the Neocene which occur in this area. Chapter XIII SALT AND GYPSUM The salt deposits of the coastal region of Texas are of great extent and are scattered over a wide area. DOMES By far the most important deposits are found in connection with the domes which occur as Cretaceous islands in the Eocene of the interior and those of later age which are found nearer the Gulf scattered through the Neocene belt. In addition to the inexhaustible supply from these sources a large number of Salines or salt springs occur in connection with palustrinal deposits of the Eocene, many of which could be utilized for the production of salt as some have been during times when other supply was less readily available. The best known of the salt domes within our area is that southwest of Palestine, a brief description of which was given in connection with the Cretaceous formations of the region. The core of this dome is a body of rock salt of unknown extent, the presence of which was ascertained by wells drilled into it. The salt was found at a depth of 140 feet. The wells so far drilled indicate that the top of this salt mass or boss is elliptical in form, the major axis having a length of more than four thousand feet. The surface of the salt is somewhat irregular. In the vicinity of the lake the top of the salt seems to be nearly level but to the north and west the wells show a pronounced dip in it. Hopkins says of it^ : "Most of the wells reach rock salt at a depth of about 140 feet, or about 160 or 170 feet above sea level the small differ- ences in the depth being due to the surface topography; the upper surface of the salt is thus fairly level in the area near the lake. In the second farthest well to the northeast from the lake, however, the top of the salt was found at 77 feet above sea level, thus showing that the salt mass has a pro- ' Bulletin U. S. G. S. 661, p. 261. 308 University of Texas Bulletin nounced dip to the north from the nearest well to the south- west. A well drilled near the western margin of the lake on the west side of the railroad penetrated a jumbled mass of rock and shale to a depth of 500 feet without reaching salt; another well near the northwest margin of the lake pene- trated 360 feet of rock without reaching salt. It thus seems that the salt mass dips strongly to the west and reaches a con- siderable depth near the western margin of the lake. No wells have been drilled on the east or southeast side of the lake, but it is inferred from the topography that this area is underlain by salt at no great depth. "The shallow salt wells penetrate about 85 feet of gray to yellow water sand and 40 feet of dark-^ray to black sandy clay, below which is in places a cap rock of hard limestone of varying thickness. The casing is set on this rock and the well deepened through sand until rock salt is reached at about 140 feet. The main factor controlling the location of salt wells is the presence of a good cap rock which serves as a seat for, the casing and also holds up the overlying strata until a large cavity is dissolved out underneath it. "When the supporting salt is sufficiently removed this rock, being undermined, caves in, with the overlying formations, forming a large sink hole." The production of salt at this locality began many years ago, but was discontinued from tim£ to time. Recently it has been renewed and a modern plant has been erected which produces a large quantity of salt of various grades. The Keeehi dome is also underlain by salt but the body of salt is so far down that it can not be utilized under present conditions. The log of a deep-well drilled in this dome shows rock salt from 2200 feet to 3030 feet with 30 feet of water bearing sand at 2900 feet. The Butler dome has not yefbeen drilled. Consequently, we do not know what its possibilities as a salt producer may be. The salt of these Cretaceous domes probably had its origin in the evaporation of seawater in shallow bays during the period of Comanchean sedimentation or the Mid-Cretaceous interval. The Geology of East Texas 309 SALINES Throughout the East Texas region there is a series of low de- pressions generally known as "Salines" or "Salt Licks". These • are irregular in size and depth — some cover only a few acres, while others cover extensive areas. Some are destitute of vege- tation, some have occasional tufts of short grass; others have a sparse covering of salt loving plants, while the more extensive ones generally develop into palmetto covered flats. Throughout the wet season these salines are mostly small ponds or marshy places, and during the summer or dry seasons they form bare spots. Some of these salines have small springs of salt water which flow during the driest season, and some of the larger ones have their surface dotted with small irregularly spaced mounds. Areally these salines extend over a wide stretch of country and the more important ones may be said to be associated with the main lines of drainage of the region. They lie in the low flat lands bordering the Sabine, Angelina and Neehes rivers. A few, such as the Saline on Texas & New Orleans Section 17 in Sabine county, another about three miles south of Jasper, in Jasper county; a Saline near Moscow in Polk county, and Mc- Kim's Prairie near Groveton, in Trinity county, appear to form the main exceptions to the rule of the salines being connected with the river drainage channels. The salines and salt springs occurring near Sabinetown on both sides of the Sabine and near the mouth of Bayou Negreei belong to the Wilcox, "Big Salt" northeast of Lufkin, Bluff Saline and two smaller salines on the Angelina and Attoyac lie within the limits of the Yegua beds and Bear Creek, McKim's Prairie with possibly Stiver, Graham's and a large saline near the mouth of Ayish Bayou are all within the limits assigned to beds of the Jackson age. Graham's and Stiver's are somewhat doubtful as they lie in depressions apparently eroded in the Catahoula sandstones but near the contact with the Jackson. A large salt water spring occurs near Rockland and the waters from this come up through broken beds of the hard gray sandstone found north of Neehes river in this region. The saline south of Jasper and probably the one near Moscow belong to the Fleming division. 310 University of Tfixas Bulletin It may be remarked here that not a single saline has been seen anywhere in the territory occupied by the Cook's Mountain or Mount Sebnan divisions of the Marine beds and although pal- metto flats are common in the other divisions and more particu^ larly so within the limits of the Yegua and Jackson formations these are also entirely absent in the Cook's Mountain and Mount Selman divisions. Thus the Salines are practically restricted to those formations which are largely composed of palustrinal deposits. ORIGIN OF SAIilNES The source of these salts may be placed in the Lignitic, Yegua and Jackson formations, which formations are highly saliferous, while the marine formations of Cook's Mountain and Mount Sel- man divisions are much less so. The Lignitic beds, as well as those of the Yegua and Jackson, carry large quantities of selenite and sodium chloride. The greater number of these salines, es- pecially those occupying the higher grounds, are associated with springs of salt water. These springs often carry other salts, such as magnesia, lime and sulphur, and by underground erosion, if we may call it so, due to the solution and carrying away of these salts, the bottom of the saline has been gradually lowered until it has reached its present condition. The springs, while fairly numerous, are never very large, but in most instances only rise a few inches above the general level and the water bubbles over a few yards to be lost in the associated sands. Many of them bring up small pebbles, thus forming a small cone arpund their vent. The springs are, of ten intermittent, but some flow even in the driest period of the year. Efflorescence of saline matter is not so conspicuous in these salines as in the lower ones and it is possible that the greater portion of the salt is carried off by the running water. In the salines with springs portions of the floor is often covered with a sparse growth of coarse grass or palmetto. Owing to the structure of some of the salt domes, such as King's and Rathbone's domes in northwestern Louisiana, it has been suggested that the larger of the salines may indicate the presence of similar salt domes. "Wells have been drilled to con- The Geology of East Texas 311 siderable depths at these localities and no evidence of the pres- ence of salt beds has been observed. MOUNDS IN ASSOCIATION WITH SALINES Many of thse salines have small mounds, or as they are some- times designated, "mud volcanoes", connected with them. Occa- sionally these mounds lie around the margins of the salines, but throughout the greater , number examined the mounds occupy prominent positions upon the surface of the saline. Mounds occur in connection with the Ayish bayou saline and here they dot the surface as well as occurring around the outer margin. On "Big Salt" Saline in Angelina county, Bluff Prairie, Mc- Kim's, Graham's and several other salines these mounds appear almost altogether to rest upon the surface of the saline. Although these mounds are frequently referred to as mud vol- canoes, there are no mud volcanoes, such as have been described as existing in some of the oil fields of the world, known in this portion of l"exas, nor in the adjoining portion of Louisiana. The only condition approaching these mud volcanoes are the so-called "suck holes". These suck holes or quaking bogs were observed n the Neches bottom four and five miles from Blix. Here the quaking por- tions of the bog are from four inches to one foot above the sur- rounding surface. The surface layer is hardened and cracked and underneath this is a light-blue liquid mud at least 12 feet deep. Beneath this was a brownish colored fine sand and upon stirring with a pole the mud gave off a few bubbles of non-in- flammable gas. The blue mud has an odor of sulphur. SALINES OF THE WILCOX There are a number of small salines and salt springs belong- ing to this formation along the eastern side of the Sabine river, from which it is reported salt was obtained by the earliest set- tlers and during the Civil War. So far as our investigation go, there appears to be only one on the western bank of the river This is a saline on Section 17, Texas & New Orleans Railroad lands. This saline occupies an area of approximately 10 to 15 acres 312 University of Texas Bulletin surrounded by a slightly elevated sandy ridge. The surface ma- terial is a grayish while sand sparsely covered with a growth of short bunch grass. The bare spots show an efQorescence of salt during dry weather. Dotted over the surface there are a num- ber of sinall mounds rising to heights of 6 to 7 feet and having diameters ranging from a few feet up to 30 feet. A number of small springs of salt water rise from the bottom of the saline and a shallow pit dug for water for drilling purposes gives a fair supply of a strong brine. A weU drilled to the depth of 1500 feet gives no evidence of the existence of a body of salt in this saline. SALINES OF THE YEGUA "Big Salt Saline — This saline lies in Angelina rivep bottom about one mile east of the Texas & New Orleans Railroad bridge in northern Angelina and southern Nacogdoches counties. It occupies a depression along the stream which is from 12 to 15 feet below the level of the surrounding country. The depresssion is covered with cream-colored sand ijnpregnated with salt, which locally forms an incrustation on the surface. Its surface in places slopes down to the level of the water in the river, but in other places the river has cut a bank from one to three feet thick below its general level. Vegetation is sparse over the saline and there are patches of considerable extent where the glistening white sands are entirely bare. Some patches are covered by short grass to the exclusion of other vegetation. The palmetto is one of the abundant plants on the saline. Shallow depressions are occupied with ponds of turbid water. There are several island-like masses, some of which cover acres in extent and rise two or three feet above the general surface. There would appear to be a perennial source of supply of the salt, otherwise the water flowing through the middle and covering it with its flood waters would have been likely to have long since dissolved out the salt. The depression occupied by the saline may have been caused by a leaching of the salt slightly faster than its precipitation. During the Civil War the saline was worked for salt to supply The Geology of East Texas 313 the local demand. The salt water was secured from shallow wells and the salt evaported in iron kettles, wood being used for fuel. Bluff Prairie Saline :— This saline lies in the vicinity of Vair Station on the Texas Southeastern Railroad in eastern Trinity county and in the flood plain of the Neches river. The saline begins in the vicinity of Vair, 600 feet southwest of Vajr Station. On the south it extends about one half mile south of the tracks of the Texas Southeastern Railroad. On the east it merges into the second bottom of the Neches and on the north into a larger saline known as Bluff Prairie. The southern saline is known as Cedar Brake Prairie. Bluff Prairie extends almost to the river at a place 11/2 miles north of the railroad. The surface of Cedar Brake and Bluff Prairies is incrusted with salt during dry weather. The surface soil is a fine white sand. The saline supports a scanty growth of scrub trees and palmetto. In places the surface is entirely bare. The level surface of the prairie is interrupted here and there by low circular or elliptical mounds varying from 2 to 4 feet in height and from 10 to 40 feet in diameter. Small pines or oaks grow on these mounds when the surrounding lower surface supports no arborescent vegetation, but here and there a hawthorn tree grows on the lower surface. SALINES OF THE JACKSON Ayish Bayou Saline : — This saline lies about twelve miles north of Jasper between Ayish bayou and the Angelina river and covers only a few acres. The surface is bare and sandy and is surrounded by an elevated rim from five to seven feet high. The material forming this elevated margin appears to be the same as that forming the mounds found within the saline. The water found in small pools is saline. Small limy concretions occur in considerable quantities both on the mounds and surrounding high ground. GrwKum's Saline: — This saline is located near the Catahoilla- Jackson contact, but from its low level it has been considered as of Jackson age. The saline proper lies on the north side of the Neches river and along the banks of Gra- 21-ET. 314 University of Texas Bulletin ham's creek and covers an area of probably twenty acres. The surrounding region is comparatively high and made up of brown sands and sandstones. The surface of the saline is a gray sand, bare in many portions, some of which are over 200 yards in length and between 50 and 75 yards in width. Other portions are covered with palmetto. Some portions of this saline are covered with low mounds from 15 to 20 feet in diameter. These mounds are mostly covered with pine trees. Several salt springs appear in the bottom of the saline and a very strong bold spring of salt water occurs a short distance from its eastern end. Several wells have been drilled in and around this saline to depths ranging from 700 to 2900 feet, all of which showed heavy flows of hot salt water with a little oil. Well No. 3 produced about 3 barrels of oil with several hundred barrels of water daily. "Well No. 9 produced about 10 barrels of oil and over 1,000 barrels of water daily for several weeks. These flows were always accompanied with heavy volumes of sul- phuretted hydrogen. No salt beds were found in any of the wells. Well No. 3 and No. 4 provided a small fauna of Marine (Cook's Mountain) fossils. The first from about 800 feet and the second from a depth as near as could be ascertained of 1200 feet. It is said salt was made here during the Civil War, but no record is obtainable as to its quality or quantity. Stiver's Saline: — This is a small saline near the mouth of Shawnee creek on the Neehes river. It is much smaller than Graham's Saline, but very much resembles it. No wells have been drilled in this saline, but it is reported salt was made from the brine from small wells sunk to a shallow depth during the Civil War. Shawnee creek runs across the western end of this saline and hard sandstones occur in the bottom of this stream. The ridge along the northern and eastern borders is made up of chocolate colored and grayish clays and sandy clays with thin seams of soft white sandstone near the top. McKim's Pra/irie: — McKim's Prairie is located in the southwestern portion of the Jose L. Lopez league in Trinity The Geology of East Texas 315 county and close to the southern boundary line of the Jackson area. This prairie covers an area of 100 to 150 acres, the greater portion of which is covered with small mounds and spots of salt incrustation. Some shallow wells have been dug at various localities but none of them exceed 35 feet in depth. SALINES AS A SOURCE OF SALT It is reported that by the earlier settlers and during the Civil War salt was made by boiling the salt water found at several places along the Sabine river. Hilgard mentions salt having been made in a flat two miles south of Myrick's Ferry, Sabine Parish. Salt was also made from the water of a saline near Stone Coal bluff and near the mouth of Bayou Negreet. Salt is also reported as having been obtained from "Big Salt" Saline near Lufkin. GYPSUM Throughout the Tertiary deposits in Eastern Texas, great quantities of gypsum, mostly in the form of selenite, makes its appearance. In some of the divisions it is more abundant than in others ; thus, it is plentiful in some portions of the Midway, present, but somewhat sparingly, in the Lignitic; entirely wanting in the Queen City beds; very sparingly distributed throughout the lower division (Mount Selman) of the Marine; abundant in the upper or Cook's Mountain division, particu- larly near the top of these beds. Selenite crystals are even more abundant throughout the Yegua, which succeeds the Cook's Mountain, but almost entirely absent in the Fayette sands, although in the overlying Jackson clays these crystals again appear in great numbers. Near the top of the Cook's Mountain beds there are large deposits of selenite and in some localities the crystals acquire a large size and most of them are almost, if not altogether, perfect in form. Many of them are twinned. Amongst the localities in which these crystals occur in great profusion may be mentioned a black sand near Forest in Cherokee county; near the contact between the Cook's Mountain beds and Tegua clays a few miles north of Bryan in Brazos county, where they aeeur in a yellowish sandy clay and associated with Claiborne Eossils ; near the southern base of Cook 's Mountain in Houston 30unty, a few miles east of Crockett. Here the crystals occur plentifully scattered through a black sand and lie in bunches a cew inches apart. The crystals found in this region are as a rule perfectly formed and but rarely twinned. In addition to the greensand marls and pyrites, the water found throughout the region occupied by these Marine deposits s for the most part alkaline in nature. The destruction of ihe pyrites sets free more or less suphurous acid, which soon changes to sulphuric acid, and this, by attacking the lime car- Donate of the shells, forms gypsum which goes into solution, is 5arried downward into dark carbonaceous sands and is there Jreeipitated in the form of selenite crystals. The Tegua is very prolific in selenite crystals ; almost every- where, where the clays of this division are found, these crys- ;als are plentifully distributed through them, and it is difficult io find any source within this division from which these crys- ;als may have been derived. These beds immediately overlie ;he Marine beds with their abundant supplies of carbonate :>£ lime, sulphuric acid and alkaline waters, and it may be possible that the gypsums now found in the Yegua deposits went into solution in the Marine deposits and were carried up mto the Yegua and meeting with its carbonaceous matter were deposited in the form we now find them. It may also )e possible that particles of lime carbonate were distributed throughout these clays as original matter and that the de- struction of some of the iron pyrites occurring in them set free jnough sulphuric acid to form the crystals, but in the light of what is known of the structure of other clays of Miocene and Pliocene age carrying gypsums in another form, it is more ikely that the selenite crystals came into both this and the jverlying Jackson division in solutions carried by water. Dead pyrites in the form of what the lignite miners call sulphur balls occur in both divisions. Many of the Jackson clays are highly calcareous, the white colored ones especially so. The darker clays resemble the The Geology of East Texas 317 Yegua clays, in that they are liberally sprinkled with selenite crystals. Sulphur water also occurs in this Jackson division. These Tertiary gypsums are interesting only from the pecu- liarity of their position and the conditions under which they occur. They are of no practical commercial value. M/ITU no A\Al CHAPPTER XIV. IRON Inteoduction Although much has been written regarding the extent and quantity of the iron ores of East Texas development has been very slow. General descriptions of the ores were given by several of the early writers and attention called to them by Shumard and Buckley. In 1890 the Geological Survey of Texas published as part of its Second Annual a report on the region subtitled "The Iron Ore Regions of East Texas" in which after a gen- eral historical introduction, as full and detailed a description of the ore beds, and deposits was given as the facilities afforded us could compass. It included a map giving, approximately, the location and area of deposits of workable ore, descriptions of the beds at many localities and analysis of what we believed to be average ores of the various localities. Kennedy summarized and discussed the results of this work and added later observations on it in a paper published in the Transactions of the American Institute of Mining Engineers in 1894 entitled "Iron Ores of East Texas." Phillips republshed the map accompanying the report in the Second Annual Report of the Geological Survey with some additions and wrote several descriptive articles for journals devoted to the iron trade. Burehard in Bulletin 620 of the United States Geological Survey has a report on "Iron Ore, in Cass, Marion, Morris and Cherokee counties, Texas, ' ' in which he descril)es the work done in the investigation of the deposits preparatory to open- ing them tip in a larger commercial way. Prom the various openings made for testing the beds he was able to give a much clearer idea of their character and extent than was possible previously when only surface exposures were available. Probably the greatc'f Oitrt of the ores are limonites or other hydrated oxides of iron which are popularly known as brown The Geology of East Texas 319 ore. There are, however, considerable bodies of carbonate ores (spathaic iron or sphasrosiderite) and the limonite and siderite are found grading one into the other. Both classes of ore are usually, if not universally, associated with glaueonitic sand. Burehard states that ore bodies of any extent are only found in such connection and are wanting in bodies of siliceous sand. When the glaueonitic beds are unaltered they frequently carry considerable amounts of spathic iron as nodules and boulders. In the beds of altered greensand these boulders of spathic iron are largely altered to limonite which also occurs through the sands in other than nodular forms. It is probable that a large part of these iron ores have their origin in the siderite and that the iron of the glaueonite and pyrite have contributed only a minor percentage to the mass of workable ores. The origin of these ores has been discussed at some length by Penrose in the First Annual Report of the Geological Sur- vey of Texas and in his report on "The Iron Deposits of Ar- kansas" in volume one Qt the Report for 1892 of the Geological Survey of Arkansas. The workable ores are of two classes: The nodular, geode or concretionary and the laminated. Kennedy describes the nodular ores as follows^ : The nodular ore is usually found in the form of irregularly-rounded, oval and flattened or ellipsoidal nodules or boulders from a few inches to one or two feet in length. Outside, these present a smooth appearance and dull or earthy brown color. When broken, the shell presents a striated appearance of yellow and brown colors, formed by the alternate concentric rings of iron- ore and oeher. These striations usually do not exceed one- fourth to one-half inch in thickness, but in some of the larger nodules the iron has a thickness of over an inch, and in many the yellow ochreous concentric rings are absent, in which case the whole shell, with the exception of the brown outer covering, is dark blue. The interior coating of the shell is often a glossy black. Many of these concretions are hollow, a great number, however, have the interior filled with a core of brown ' Iron Ores of East Texas, p. 14. 320 Vniversiiy of Texas Bulletin or yellow ocher, similar to that forming the yellow, rings; others have dendritic formations of ore spreading through the center and having the ends fastened to the inner side of the shell. Some few, particularly of the flattened oval form, have the entire center filled with convolutions of the inner ring. Most of the rounded forms are either empty or filled with the same character of yellow sand and amongst which they lie. Buehard says^ : Both the brown ore and the iron carbonate occur in nodular and geodal forms segregated in glauconitie sand and clay in thin lenses and irregular ledges, and also as more or less honey-combed thin sheets and layers, fine frag- ments, crusts, small isolated nodules, and irregular masses of almost endless variety. Unconsolidated material, residual from the breaking down of such masses, is found in many places at the surface. Bowie Hill in Cass county^ ( 1) shows the manner of its occur- rence excellently: Generalized section or ore-bearing beds on Bowie Hill. Residual fragments of limonite in top soil, in places practically solid ore gravel . . ■ ■ 1-3 ft. Ledge of nodular limonite, more or less solid % to 1% ft. Scales and thin bands of limonite with a few thicker layers or ledges interlaminated with glauconitie sandy layers. The limonite in this condition, ranges from pieces of the thick- ness of small chips up to masses 1% feet thick and is scattered through yellowish to red sand and clay. It occurs in overlapping, roughly lenticular streaks, or broken and discontinuous seams. The limonite constitutes, in the sections observed, 20 to 30 per cent, by volume, of the dirt. Thickness of limonite sand and clay 12-15 ft. . Iron carbonate in nodular masses from the diameter of an acorn up to 6 inches, or in thin irregular lenses, embedded or interstratifled in glauconitie sand and greenish-black clay called "buekfat" clay. The iron carbonate is in general partly altered to limonite or to reddish hydrated oxides of iron, which form a scale or crust of varying thickness around the carbonate nucleus and along cracks which inter-, sect the masses. Thickness of exposed portions of unox- idized beds 1-5 ft. •- Bui. U. S. G. S. 620. p. 74. 3. Idem, p. 76. The Geology of East Texas 321 The laminated ores* vary in appearance as well as texture and tKiekness. In places, these ores occur in thin laminse of dark brown or chestnut color, interstratifled with similar laminse of bright orange or yellow. These laminae rarely exceed a quarter of an inch in thickness. At other places, the ores become more massive, occur in beds from two -inches to as many feet thick, and vary in color from a dark chestnut-brown to a lighter shade of the same color, with small irregularly disseminated patches of yellow showing throughout the mass. This ore also occurs in thin wavy lamince of from chestnut-brown to black color, usually having the spaces between the laminfe filled with fine clayey ma- terial. This grade is usually of a very crumbly nature, hence the name given to it of "bufE crumbly." The laminated ores have also been made to include the botryoidal and mammillated forms frequently found intermixed with other ores. In addition to these two classes of ore there is a considerable quantity of iron ore of a conglomeratic character spread over the country which is not rich enough in iron to be considered an iron ore. While ores of both these classes are at times found together the workable bodies of nodular ore occur principally in con- nection with and interbedded in the Mount Selman deposits lying, between the Sulphur and Sabine rivers. Similar ores occur south of the Sabine in the same association as well as in the Cook's Mountain beds overlying them, but they are not present in such quantity and so far as now known are not so promising com- mercially. Laminated ores are also found in the Mount Selman in con- nection with the nndnlar ores but the bulk of this ore occurs as a blanket formation overlying the beds of the Cook's Mountain. The ore forms a practically continuous bed extending over con- siderable areas. It varies in thickness from a few inches to 6 or 7 feet and is usually overlain by sands. By its resistance to erosion it has been the preserver of parts of the ancient plateau country in .Anderson, Cherokee, Kusk and Harrison counties. * Iron Ores of East Texas, pp. 14-15. 322 University of Texas Bulletin SHELBY COUNTY ORES Beginning four miles northwest of Timpson there is a broad ridge or plateau extending into southwestern Panola county. This ridge is capped by a deposit of iron ore that is apparently of workable thickness and this is underlain by beds of altered greensand with some nodular ore. The section is as follows: 1. Sand 6 ft. 2. Ferruginous sandstone 6 in. 3. Laminated Iron ore ti in. 4. BufC crumbly iron ore 3 ft. 5. Altered greensand with nodular and geode ores 4 ft. 6. Sandy clays. Analyses of these ores give the following: Sesquioxfde Silica Alumina Phos- Water Metallic of iron phoric iron acid Laminated Ore 64.23 21.20 11.77 0.80 1.80 44.96 Buff crumbly ore 50.72 40.45 7.68 0.25 0.80 35.50 While there has been no development at this locality, the presence of a body of ore of this area and of the quality indi- cated by the analyses should insure its proper investigation whenevej" a market for these ores is available. NACOGDOCHES COUNTY ORES During the years 1863 and 1864 the McLain bloomary operat- ing in the vicinity of Linn Flat, ten or twelve miles north of Nacogdoches, produced 150,000 pounds of hammered bars from the ores of that vicinity. Seventeen miles northwest of Nacogdoches there is an elevated area kno^vn as the Brewer's Mountain region. This plateau stretches about four miles east and west vdth a width of two and one-half miles. This is apparently the southeastward extension of the plateau in Eusk county as Elkins or Iron Mountain of similar form and materials lies only seven miles to the north- westward. Brewer's Mountain is capped by a bed of buff crumbly ore which, where it is exposed, shows a thickness of from two to two and one-half feetl The Geology of East Texas 323 RUSK COUNTY ORES In the southwestern portion of Eusk county there is a plateau area of which apparently fifteen square miles are capped by iron ores. This is known by the local names of New Salem, Iron Mountain at Gould and Iron Mountain at Glenfawn. The ore is laminated and buff crumbly and varies in thickness, sometimes, as at Glenfawn, being as much as forty inches thick. Taken as a whole the thickness will probably aver- age three feet. The New Salem area four miles north of the station of Eick- law, on the Texas and New Orleans Eailroad, has been pros- pected to some extent. It is estimated that some 6,000 acres are covered with the laminated ore, varying from one foot to five feet in thickness, and selected samples of the ore run as high as 55 per cent of metallic iron. An average of 52 samples of lam- inated ore from this area gave: Iron 45.25 Phosphorus .248 Sulphur 057 Silica • ■ • • 12.19 Alumina 8.67 Lime trace Magnesia • ■ iJ4 Combined water, etc. 13.44 Those ores, while high in alumina, will make an excellent foundry iron or one well suited to the manufacture of open hearth steel. CHEROKEE COUNTY ORES The most extensive remnants of the limonite capped plateau are found in Cherokee county, forming the divide between the Angelina and Neches rivers. Beginning near Mount Melman this plateau extends thirty miles south- eastward to Alto with a width of more than ten miles, but it has been dissected by streams tributary to the rivers named into a number of flat-topped hills or mesas. These hills and mesas vary from a few acres to thirty square miles in area and aggregate approximately three hundred square miles. 324 University of Texas Bulletin The ore districts of this county were mapped by Penrose and his general description of them was given in the First Annual Report of the Geological Survey of Texas from which the fol- lowing extracts are taken: The ore belt in this county begins at its southern end, about three miles north of the town of Alto, and runs in a north- westerly and north northwesterly direction through the county into the southern part of Smith county. Going north from Alto the ore is found capping small flat-topped hills and nar- row ridges, of limited extent, until we come within five miles • of New Birmingham. These ore-bearing areas show the ususal brown laminated ore, but near Alto, their extreme southern limit in the county, it has not reached its full development and continuity as seen to the north of it. The ore is thin, and the hills are scattered, small, and form isolated points, which though low in absolute elevation lock high and imposing in comparison v/ith the surrounding flat or gently undulating country. Such eminences are Collins Mountain, Taylor Moun- tain, Carter Mountain, and many others, varying from one hundred to one hundred and fifty feet above the surrounding drainage level, and some five to six hundred feet above the Gulf of Mexico. In this region, eight miles northwest of Alto, was situated the old Philleo furnace. It was worked during the Civil War, but abandoned immediately after that time, and it was from the immediately surrounding region that it drew its supply of ore. Five miles southeast of New Birmingham we ascend the southern extremity of the main iron range of central Cherokee County, which extends thence in an un- broken table land, running off to the northwest for over twelve miles, and varying from one-half to three miles wide. It bears to the north and east of the towns of Rusk and New Birming- ham, and finally ends abruptly at Doyle's Gap, seven miles above Rusk. Throughout this whole area the character of the ore and its associated beds is identically the same. The ore varies from one to three feet thick, is of the usual chestnut color, and is overlain by from three to ten feet of gray sand. The town of New Birmingham is built on the western slope of this range at a distance of one and a half miles southeast of The Geology of East Texas 325 Rusk, the county seat of Cherokee County, and is the location of the furnaces of the Cherokee Land and Iron Company. .Doyle's Gap is a narrow break, half a mile wide, in the main range, and to the west of it we again ascend the northeast cor- ner of a similar iron-bearing plateau. This is the eastern part of what is known as the Gent Mountain country, which extends .hence in a southwesterly direction to within eight miles of the Neches river. Going west from Rusk we strike the southern part of tht Gent Mountain range in six miles, and in about four miles farther reach the village of Gent, situated on the southwestern corijer of the plateau. This range is almost cut in two by Horse Pen and One Arm creeks, running respectively north land south from the summit, but the two parts are con- nected by a narrow neck of ore-bearing land. This area is some six miles long by four to five miles wide and is almost continuously underlain by iron ore. From the Summit of Gent Mountain can be seen the sloping country to the west, running to the swampy bottom of the Neches, some eight miles distant. Beyond the river the country can be seen gradually rising into the forest-cLad hills of Anderson County. To the south the low, flat, or undulating country forming the Neches and Gum Creek bottoms spreads out in rich pine and gum tree thickets. To the east and north are seen the ore-bearing highlands of central Cherokee County, covered with a thick growth of hickory, blackjack, and post oak, and extending on the east beyond Rusk, and on the north to within five miles of Jackson- ville. Gent Mountain is some three hundred feet above the Neches River. For the first two hundred feet the slope is very rapid and then drops more gradually to the river. The following section on the slope of the plateau and just east of Gent shows the occurrence of the ore: 1. Gray or buff colored sand 1 to 10 ft. 2. Siliceous sandstone capping 1 to 2 in. 3. Brown laminated iron ore 2 ft. 4. Indurated greensand' with thin seams of clay and casts of fossils 45 ft. 5. Coarse white clayey sand 20 ft. 6. Dark blackish-brown sand, more clayey towards the base, nodules of rusty clay ironstone showing shrinkage cracks. 31 ft. 7. Brownish-gray sand to base - of section 11 ft. 326 University of Texas Bulletin To the west and northwest the Gent Mountain range is bounded by Grum Creek, and beyond it the iron-bearing plateau again becomes broken up into numerous flat topped hills and narrow ridges, extending from Gum Creek to the International and Great Northern Kailroad, and beyond. The railroad takes advantage of this break in the main range to pass through the plateau country, and it is the only east and west pass in a distance of over twenty-five miles. Among the most prom- inent of these isolated hills are Iron-Furnace Mountain (the location of the old Young furnace), Gray's Mountain and Grimes Mountain. Beyond we come to another iron-bearing plateau. It begins in its southern extremity at Ragsdale Moun- tain, three miles west of Jacksonville, and extends on the north to the old town of Larissa, where again it is cut off by Killough Creek. This range is over six miles long, and three miles wide in its widest part. On the east side it slopes off in a series of fertile red and mulatto soils into Gum Creek bottom, which separates it from the Mount Selman range. On the west slope of the plateau is a broad fertile agricultural country, with soils similar to those on the eastern slope, and reaching to the Neehes river, a distance of five to eight miles. The ore is of the same general character as that already described. It varies from one to three feet thick, is capped with the usual one to three inches of hard brown sandstone, and one to six feet of gray sand. The prosperous town of Jacksonville is beautifully situated three miles east of Kagsdale Mountain, and on the southwest- ern slope of the Mount Selman range. The International & Great Northern Railroad enters the town from the southern end of th.e range, and the Kansas and Gulf Short Line comes down the southwestern slope, intersecting the International & Great Northern at Jacksonville. Going northeast from the tovm, the summit of the plateau is reached in about one and a half miles. The ore shows itself in the gullies and breaks of the mountain slope, and is of the same character and thick- ness as that described on Gent Mountain and elsewhere. The range is of the customary plateau character, is twelve miles long, and varies in width from a hundred yards to a half mile. The sand cap overlying the iron here is much thinner than on The Geology of East Texas 327 many of the other iron-hearing ranges, and often the bare ore bed is exposed directly on the surface of the ground, thus add- ing greatly to the value of the deposit, as the mining of it re- quires but little or no stripping. The absence of this covering is doubtless due to the narrowness of the range, which has made it easy work for the surface waters to wash away the loose sand, and also to a westerly dip of the iron ore, which has still farther facilitated the erosion of the surface deposits, by allowing the superficial waters to run off at a rapid rate, and all in one direction. This westerly dip is peculiar to this plateau, and extends along it throughout its whole length. It is doubtless due to a local sinking to the west of the underlying strata, prol)ably before the formation of the iron ore, and also before the plateau was cut out of the Tertiary strata. At Mount Selman, eight miles n'orth of Jacksonville, the ore on the eastern brink of the range is seventy feet higher than it is on the western side, less than one mile distant. Another result of this dip is to make the eastern slope of the range very steep, and in some places perpendicular, while the western slope drops off much more gradually toward Gum Creek bottom. Mount Selman is simply a part of this range, and the village of that name is situated directly on the summit of the plateau. To the north of it the ore extends for four miles, and reaches its terminus at a point one mile south of the Smith County line, and a little greater distance southeast of the village of Bullard. Here the range ends in a small flat-topped hill a hun- dred yards long by ten to thirty yards wide. The Kansas and Gulf Short line follows the crest of this ridge from below Bullard to within three miles of Jacksonville. A short distance south of this is McKee's Gap, which is a narrow break in the top of the plateau and is the only inter- ruption in the continuity of the iron ore throughout its whole twelve miles of extent. The ore of this area is of very regular thickness, varying from two to three feet. The following sec- tion on the eastern slope of the range south of Mount Selman shows the occurrence of the ore : 1. Gray sand to 2 ft. 2. Brown laminated ore 2 to 3 ft. 328 University of Texas Bulletin 3. Indurated greensand 30 ft. 4. Detritus. This region forms the divide between the waters of the Nechcs River on the west and Mud Creek, the headwaters of the Angelina River on the east. It reaches its highest eleva- tion at Mount Selman, where it is seven hundred feet ahove the fiea. From here north to the limit of the iron ore there is hut little change in height, but from there to Tyler it drops off to 531 feet. To the south of Mount Selman the plateau main- tains almo.st the same elevation to within a mile northeast of Jacksonville, when it rapidly slopes off to 525 feet at that town. From Ihe .summit of the ridge the land slopes off on the east very abruptly for a hundred feet, and sometimes shows two or three successive benches ; thence the grade is more grad- ual down to the settlement of Little Arkansas and to Mud Creek bottom. To the west the grade slopes off in gently un- dulating hills, with a rich growth of pine, oak, and hickory, and watered by numerous creeks and springs. The hills on which the ore occurs are steep and show a broad flat plateau-like surface, heavily capped with post oak, blackjack and hickory, generally of a small size, but very dense. The ore crops out on the brink of these hills, forming a protruding rim or crown, and often covering the slopes with great masses which have broken off from the main bed. These plateaus are sometimes as much as twenty square miles and more in area. They are often deeply cut by the ravines of creeks which have originated in springs in the superficial sand and which flow away from the plateau in all directions, cutting deep gullies and exposing the ore bed along their courses. On top of these plateau areas the covering of sand often conceals the ore for a distance of several miles at a time but it is always found chopping out at the top of the slopes, and in wells, proving its continuity over very large areas. The ore occurs in a horizontal bed from one to three feet thick, and averages between eighteen inches and two feet in thickness. It is flat on top, but is bulging and mammillary below and lies at or near the summits of the highest hills in the region. In fact, it is to this protecting cap of hard material The Geology of East Texas 329 that the hills owe their existen'ce,' as it has saved the 'undW- lying soft strata from the effects of erxreferas^Wliiohss^eMe^?^ would quickly have lowered them to the l^Wie©* -tfig' '§ffi?P^ffii#- ing rolling country.- The iron ore bed is directly undSrlaiiPby a deposit varying from thirty to forty feet thick of a' soft yellow indurated glauconite (greensand). This bed is some- times hardened into a soft rock, easily cut with a -saTv or axe, and locally used as a building stone. The interior of the bed, however, where it has not been exposed to the atmosphere, retains the dark green color of unaltered greensand. The main ore bed is usually directly overlain by a thin seam of dark brown and very hard siliceous sandstone, varying from one to six inches thick, and averaging about one and a half inches. It adheres closely to the iron ore bed, though the line of sep- aration is sharp and well defined. Above this is a gray sandy deposit, becoming more clayey and ferruginoiis towards its base, and varying from one to sixty feet thick: This latter thickness is, however, very extreme, and the average is about six to eight feet. As a rule the thickness of the- ore depends in a general way, on the thickness of the overlying sand bed, it being thicker where the sand is less than fifteen or twenty feet than where it is greater. Burchard reports on the development as follows^ : Among the best exposures are those where the ore has been mined, as, for instance, at the several State mines, 3% miles northwest, II/2 miles north, and 2I/2 miles northeast of. Rusk •, at the Star and Crescent mines, 1% miles east of Rupk; a;ad at. the mines 2% miles southeast of Rusk, worked in, connec- tion with the Tassie Belle furnace. The latest and most extensive of the State mines are on tt^e eastwest spur of the plateau, beginning about 2^2 miles north- west of Rusk. These workings, which have been . inactive since 1909, consist of open cuts and extend westward for more than 1 mile, interrupted by places where the cover of , sand is tog thick for stripping and by a ravine where the ore bed has been removed by, erosion. An unusually good opportunity w'as af- forded to the writer, in November, 1914, to examine the ore ■' Bulletin, United States Geol. Sur. No. 620, p.'92'et sei 22-ET. 330 University of Texas Bulletin bed at one place where it had been stripped over an area of about 1^ acres. The regular furrowed surface of the ore bed is particularly well displayed in. this, stripped area, and "Vvhen viewed from the top of a high bank of sand the surface re- sembles an abandoned plowed field in which the furrows are still faintly visible. The ore bed ranges in thickness from 15 to 36 inches and probably averages at least 2 feet. Adjoining the tract where the stripped ore bed is still in place piles of lump ore about 4 feet high have been stacked up over an area of about an acre. Another locality where mining was done by the State is 2 to 2% miles northeast of Rusk, around the west rim of a northward-extending lobe of the plateau. The open cut ex- tends around the edge of the hill for a mile or more, and the stripping was carried to a maximum of 10 feet, but averages much less. The ore bed ranges in thickness from 12 to 30 inches. In places it contains a streak of sand, as is shown in the following section: Section 2 miles northeast of Rusk. Sand, fine grained, gray, with soil and grass at top 7 ft. Sandstone, hard, with streaks of limonlte 1 ft. 5 in. Llmonlte, compact 1 ft. in. Sand, yellow, soft 5 in. Limonite, compact 1 ft. 3 in. Clay, white; base not exposed. In this section the "sand cap" probably is merged into the ledge of limonitic sandstone above the ore. At other places the typical layer of sandstone, about 2 inches thick, is at the top of the ore. Near the north end of the workings the sand above the ore contains 3 to 4 feet of fairly hard concretionary sand- stone, which rendered the work of stripping more difficult. Ore was carried from this place to the State blast furnace by a steam tramroad. The last operations are reported to have been carried on in 1906. A good exposure of the ore bed was noted on the west mar- gin 1% miles east of Rusk, at the workings of the Star and Crescent furnace, where the last operations are said to have been carried on in 1907. The ore measured 32 to 38 inches in The Geology of East Texas 331 thickness at this place. More ore is still available here, as the cover has not been stripped off to as great a thickness as at the State mines. Ore was trammed down to the blast fur- nace, a distance of about 1 1-3 miles. The old mines of the Tassie Belle furnace are 1 to 2 miles farther south along the west margin of the plateau, within a short haul of the furnace. These workings have lain idle for about 20 years. In one cut half a mile northeast of the fur- nace the ore bed is 27 to 29 inches thick and is covered by 3 to 4 feet of sand at the margin of the stripping. A pile of lump ore 1% to 3 feet high, 50 feet wide, and about 300 feet long has been left here. Analyses of the various ores were published in connection with the descriptions in both the First and Second Annual Reports and others are given by Kennedy in his "Iron Ores of East Texas." These show the excellent quality of these ores which are very similar to those of Rusk county. An average of many analyses gives : Iron 45.87 Silica 10.59 Aluminia 9.64 Phosphoric Acid 0.189 Sulphur 0.063 Lime 0.13 Magnesia • 0.103 Water and Loss 11.87 ANDERSON COUNTY ORES The iron ore of Anderson County is identical in every re- spect to that of Cherokee, not only in its general character, but in its mode of occurence and its origin. In fact, it is simply the westerly continuation of the same belt as has been described in that county. Going north from Palestine, the county seat of Anderson County, the main iron-bearing range, is met at about three miles from the town, and extends in a great plateau, often broken up into separate flat-topped hills, from here northerly towards Beaver, Brushy Creek, Kickapoo, and the Henderson County line. To the east this plateau 332 University of Texas Bulletin breaks into small hills extending to the Ne'ches River, and to the west it gradually disappears in the same way in the water shed of the Trinity River. This iron region forms the divide between the Neehes and Trinity, just as in Cherokee the Sel- man Range forms the divide between the waters of the An- gelina and the Neehes. The ore found here is continuous over large areas, and main- tains a very steady thickness of one to three feet. To the south of Palestine the same ore is found, but here the bed is gener- ally thinner and less continuous and the ore bearing hills are more scattered, though the ore is of very good quality. Just northwest of Palestine the first of the great range of iron bearing hills begins. Its longer axis extends nearly north- west, and it has a length of five miles by a width of about two miles, an area of nearly ten square miles. Its boundary begins in the northern part of the J. Snively survey, runs north through the western part of the S. G. Wells, crossing into the Wm. Kimbro near the northwest corner of the Wells tract. Following a general northwest course through the Kimbro tract it crosses the southwest portion of the S. Hopkins and G. W. Ford surveys into the M. Salisar tract. Its extreme northern limit is near the centre of the tract, where it turns south to near the southern boundary of the survey, and then sharply east to the corner of the Geo. Hanks, at which point it again crosses the Kimbro tract. From here it follows an ir- regular line, crossing the J. P. Burnet, G. W. Gatewood, and Jno. Shirely tracts, back into the J. Snively and to the place of beginning. The ore is of the laminated variety with some concretionary ore in places. Just east of this is a much smaller area of similar ore is found, beginning in the northeast corner of the W. Kimbro, crossing the Peter Hinds and David Faris surveys into the southwest corner of the H. Hunks tract. This deposit has a length of about two miles and is not more than one-half mile in width. The ore is similar to that just described (laminated) and has an average thickness of more than two feet. The third area of high grade ore lies to the north of the two just described and is more extensive than either. On its The Geology of East Texas 333 c of the headwaters of the Mount Praii'ie Creek have cut deeply into it, giving it a very irregular outline. Its south- east corner is about the southwest corner of the Jno. McCrabb survey, and the line bounding it passes northward through the western part of that tract into the J. B. McNealy, of which the deposit covers probably about one-third (the western) part. The line is very irregular here, and crosses into the Elizabeth Grace League, of which it covers an area of about one square mile in the southwestern corner. The line then passes north and northwest through the J. Hendry, F. D. Hanks, and P. 0. Lumpkins tracts to its most northern point, on the Jno. Chase survey. From here it passes south through the Lumpkin tract and the eastern edge of the Geo. Andring league to its south- east corner, where it turns east through the Levi Hopkins, Danl. Parker, Jno. "Wright, and S. A. Mays tracts to the places of beginning. Its area is nearly fifteen square miles. The ore is similar to that of the other localities mentioned. Lying to the northeast of this are found two areas forming divides on the waters of Walnut Creek. One of these is on the James Hall survey, the other on the Adolph D. Latlin. The two together may aggregate one square mile. Six miles east we find another series of hills in the neighbor- hood of Kickapoo. The largest of these has probably an area of three to three and one-half square miles, lying principally in the Jose Peneda grant, but covering also the southern portion of the Jose Chireno. South of Kickapoo, on the W. F. Pool survey, is a large HU capped with laminated ore. Northeast of that town are two others on the Goss survey and one on the Timmons, and three miles east another hill is found, also on the Goss survey. Just north of Nechesville are two small hills containing ex- cellent ore. "With the exception of a few areas too small to be of economic value these are all the localities at which high grade ores exist north of the railway. South of the railway two areas of similar ore are mapped. These are, however, not very exten- sive. One of them is on the "W. S. McDonald tracts the other on the H. Anglin. There is, however, good ore on the high divide between Still's and lonie creeks. It has a length of thirteen miles and an aver- 334 University of Texas Bulletin age width of a mile and a half, giving an area of say nineteen square miles. The ore on this is of a good quality, hut it is not as thick nor as continuous as the beds north of the railroad. The boundary of this bed, beginning in the western part of W. Frost league, passes in a direction northeast by east through the north- ern portions of the P. Martin, R. Erwin, and Geo. Clewis sur- veys, crosses the Fien Roberts, G. Killion, W. C. Carter, W. Foreman and S. Tarborough tracts to the T. Pate survey, where it has its eastern point. From here it returns to the place of be- ginning by a line passing west though the Yarborough league, the Webb and Bennett surveys, and thence southwest through. the W. E. Huddlestone, Neville, Killion, Webb, Thos. Hill, J. E, Palmer, Jno. Swearingen, J. W. Humy, T. H. Hamilton, J. H.' Gillespie, and Wm. Frost surveys. In addition to the areas described there are several others which, on account of the thinness and siliceous character of the ore, are not of as great economic importance. One of the largest of these areas is of rectangular shape and lies between the greater high grade ore at the head of Mount Prairie Creeks and those of Walnut Creek, and forming the divide between these creeks. It embraces parts of four surveys, the Elizabeth Grace, James Hall, J. B. McNealy, and John Little. Two other similar areas occur between the first two high grade areas described and the third, lying east and west of Beaver Postoffice respectively. On the Stephen Cirist survey, south, of Palestine, there is an- other area of this siliceous ore, covering more than a square mile ; ai n iust i^fiiith of lonie Creek are two other hills capped with similar ore. The most westerly of these covers parts of the Wm. R. Wilson, A. Killough, J. Gibson, C. Grigsby, and Jose M. Mora surveys, and the other, beginning in the southeastern portion of the Mora survey, covers parts of the Kennedy, Jno. Blair, C. Adams, R. Walker, B. H. Adams, and W. W. Pharr tracts. It is hardly probable that these ores, if they can be called such, will be utilized at present. The better ores are similar in composition to those of Rusk and Cherokee counties but apparently average a little higher in iron, as most of the analyses show over 47 per cent. The Geology of East Texas 335 HENDERSON COUNTY ORES The ore districts of Henderson county were described by Ken- nedy in the Second Annual 'Report. They all belong to the class of laminated ores and the best are found in the eastern portion of the county. By far the most extensive ore region of this- county lies in its southeast corner in the district between Mul- berry creek on the north, and Caddo Bayou on the south. To- wards the east this field is limited by the broad bottom lands of the Neches Eiver, and on the west by a series of deposits of yellow sand. The boundary of this field, beginning at the south- east corner of the James McDonald headright, passes south through the Maria Trinidad Equis headright to the north side of the Juan Jose Martinez survey, then turns east to near the west side of the Thomas ChafBn headright. From this point the line curves around to the northeast corner of the E. Cazanova headright and thence with a gentle curve southwesterly to the southeast corner jDf the ^\. H. Caldwell headright. From there the ridge turns southeastward and crosses the Anderson County line on the Alfred Benge headright. The western boundary of the field passes northwesterly through the A. Benge and'D. M. Dickerson headrights into the east side of the Isaac Burton head- right. Turning northeast it reaches the southwest corner of the Juan Jose Martinez headright, and thence southwest to the southwest corner of the W. L. Scott headright. From here the ore boundary passes north along the W. L. Scott and Simon Boon headrights to Boon Mountain, on the northwest corner of the A. K. Jones headright; thence northeast to the southwest corner of along the south side of the James McDonald headright to the southeast corner. The total area of this field is nearly fourteen square miles. The region covered by this field presents a series of rounded, oval shaped, and long, narrow, steep-sided hills or ridges, having a general uniform elevation of from one hundred and forty to one hundred and sixty feet (bar.) above the bottoms of the creeks in the neighborhood. The deposits within the region and constituting the ridges are comparatively uniform in their positions, the ore deposit being found at a level of one hundred and forty feet, and where the 336 University of Texas Bulletin elevation of the ridge does not exceed this height the ore covers the surface in the form of a flat cap, broken into large boulders, frequently measuring from six to ten feet in length and four to ■ six feet in width, and having a thickness equal to the whole depth of the ore deposit. Such points of the ridges as reach the higher elevations of one hundred and fifty and one hundred and sixty feet are covered with a light gray and yellow colored sand. The iron ores found throughout the different ore fields of the county are all of the laminated variety of Dr. Penrose's classi- fication, and belong to that division of the laminated ores known as buff crumbly ore. These ores have all a uniform appearance and thickness, and are overlain throughout the whole of the re- gion by a soft brown ferruginous sandstone. This sandstone thickens towards the northeast, and is found in greater quanti- ties in the ore fields around Battle Creek than in the region around Fincastle and Boon Mountain, in the southern field. While the quantity of ore found in the region forming this field may not show a thickness of more 'than three feet, and a great extent of the area may not exceed two and one-half feet, the sides of the hills all show a large quantity of debris from which vast quantities of workable ore may be readily and cheaply obtained. The enormous erosion which this region has under- gone has been the means of removing the soft underlying yellow colored sands and allowing the ore blocks and fragments to fall down along the sides of the hills and ridges, until now these accumulated blocks form deposits of ore many feet in thickness, and which will require years of steady mining to remove before the ore beds now in place will require to be touched. It may be estimated that within this ore field each square mile of ore de- posits carries in the neighborhood of seven million tons of ore. The analyses show that these ores are fully equal to any in the region in iron content. HOUSTON COUNTY ORES No detailed examination of the iron ores of this county has been made. The ore at localities visited northeast and northwest of Crockett were rather siliceous and lower in iron than ores of the district east and north. They can hardly be classed as com- mercial ores at present. The Geology of East Texas 337 The deposits of iron ore briefly described above, all of which lie within the area mapped, and aggregate probably more than three hundred square miles of actual ore beds, are only a part and probably the smaller part of the iron ore deposits of Eastern Texas. Their distance from a proper supply of fuel and lime- stone and the lack of transportation facilities have retarded their development, but it is only a question of time when they will be opened up and form the basis of a very great industry. Chapter XV CLAYS Among the papers prepared for publication ijn the Fifth An- nual Report of the Geological Survey of Texas was one by Ken- nedy on the Clays of Texas, in which he brought together all the information then available regarding these materials. This report was never printed. Nearly ten years later Prof. Ries of Cornell University took up the investigation of the clays for the University of Texas Mineral Survey and in Bulletin 102 of the University the results of his examinations are presented. In the preface to this report he says: "In the limited time available it was out of the question to work out in detail the geological relations of the different clay deposits, but still in most instances the geological age of the de- posit was known and the main point was to determine the char- acter and possible practical value of the clays in these different formations. "The object of this is twofold, viz., to supply the land owner with some knowledge of the clay resources of his region, and to acquaint the prospective manufacturer with the character of the clays occurring in the State. To the former class a brief state- ment of the possible uses of the clay is most important; to the latter class a statement of the physical characters and chemical composition is the most useful. It should be understood that the report deals mainly with the use of clay for burned clay prod- ucts. Those seeking clay for the manufacture of Portland ce- ment will find the various analyses helpful. "The series of tests undertaken for this report are probably the most detailed ever undertaken by a State geological survey, and it is felt that the results obtained have warranted the time and effort spent. "Briefly summarized, it can be said that the work has de- veloped the presence of an extensive series of refractory and semi-refractory clays in certain of the Tertiary formations of the State. These are the Lignitie and Marine formations. They ex- The Geology of East Texas 339 tend across the State in a northeasterly direction from Bexar county to Bowie county, and are crossed by a number of im- portant lines of railroad." This bulletin records a number of clays from the area under discussion and gives in the most satisfactory way their character and qualities. In the following statements it has been freely used together with the reports of the Texas Geological Survey and our later investigations. The clays found in this area may be classified as follows: Fire clay, Pottery clay, Brick clay, Slip clay. 1. Fire clay. The term fire clay belongs to those clays which are capable of resisting fire to a marked degree, or, in other words, to those which are refractory and fuse only when exposed to a high temperature. Its use should be restricted to those clays whose fusion point is at least above that of cone 27 (3038°F. or 1670°C.) Good re- fractoriness is, therefore, the most important quality of a fire clay, whatever variation it shows in its other properties, such as plasticity, tensile strength, air shrinkage, etc. The main use of fire clay is for the manufacture of fire brick. These are made of many diflierent shapes to suit the conditions under which they are to be used. 2. Pottery clay. The clays- employed under this head are those employed for the manufacture of common red earthenware, stoneware, white earthenware and porcelain. Earthenware Clays. These are used in the manufacture of the lowest grades of pottery, such as common flower pots, etc. The main requirement of them is sufficient plasticity to turn on a potter's wheel, freedom from an excess of grit, and adapta- bility to burn to a hard, dense body at a low temperature. Stoneware Clays. These differ from earthenware clays in their denser burning character and greater refractoriness. Stoneware is usually made from a refractory or semi-refrac- tory clay, and the best results are obtained by employing a mix- ture of materials. Where the two clays are mixed together, the one is selected on account of its dense burning qualities, the other because of its low shrinkage and possibly also its refractoriness. A stoneware clay might be as refractory as one used for fire brick, but differ from it in its denser burning qualities. 340 University of Texas Bulletin 3. Brick clay includes clays which can be used for common, pressed or paving brick. Many common brick clays can be used for drain-tile or red earthenware manufacture, and most of the sejni-refractory buff-brick clays found in Texas could be applied to the manufacture of common stoneware, No. 2 fire brick, terra cotta or floor tile. 4. Slip clays are those containing so high a percentage of flux- ing impurities as to melt to a glass at the temperature at which stoneware is burned and are therefore used as natural glazes. The Tertiary beds of East Texas are largely composed of clays and sands but many of the clays carry too high a percentage of sand, lime or gypsum to be of much importance in the manufac- ture of clay products. Deposits of excellent clays do occur and are being utilized at many localities. CLAYS OF THE MIDWAY While these clays carry a considerable admixture of lime and gypsum there are localities at which they are sufficiently free of these substances to furnish a satisfactory clay for the better grade of brick p.iaking Although these clays hnve not yet been studied the practical tests that have been made are sufficient to warrant further development of them. These clays are found very well developed in the country around Mexia, southward as far as Groesbeek and northward to- ward Wortham and whatever uses they may be available for may with equal facility be applied at either or all of these three places. At Mexia the shales are bluish with yellow and brown streaks, but when ground together present a yellowish brown appearance. These clays are quite plastic when wet. As the clays of this formation carry more or less lime and selenite they may be considered a non-refractory or, at best, only semi-re- fractory. No tests of these clays looking to their chemical or physical character have been made, so that very little is known regard- ing their uses, outside the fact that they make a fairly hard pressed brick burning to a bright red. ♦ The Geology of East Texas 341 CLAYS OP THE WILCOX The Wilcox carries excellent deposits of clays fitted for nearly all uses except perhaps the finer grades of earthen- ware. Interbedded with the 'lignites there are beds of shale which are often semi-refractory and clays which, while non-re- fractory, possess excellent plasticity. In other portions of the beds a red-burning, tough shaly clay is found but the most valuable clays and those which seem to have the widest distri- bution are the grayish, highly plastic, refractory or semi-re- fractory clays which occur throughout its entire extent and are opened up at several localities between the Sabine and San Antonio. These deposits include fire clays, pottery clays and brick clays and are well suited for the manufacture of a great variety of clay products. FIRE CLAYS The better grade of fire clays are the grayish clays which seem to belong in the upper half of the Lignitic section. These were first developtd in the vicinity of Athens in Henderson county. The numerous openings show this bed of clay to be of a grayish white color and to have a thickness of from two to twelve feet. It rests upon a bed of white even- grained sand five feet or more in thickness. These sands and clays are found in association at numerous places. While the clay bed at Athens extends over an area of two square miles or more it is probably lenticular and one of several similar deposits as clay of the same character but of somewhat darker color is found at MalakofE, ten miles southwest of Athens, where it is mined and used. These clays are very refractory, the fusibility of them being those of Seger cones 27 to 30. They are used for the manu- facture of fire brick and pressed brick. While the beds of the Wilcox continue southwestward through Freestone county and it is entirely probable that clays of this character occur in them we have no record of their having been observed there. They are found again in Lime- 342 University vf Texas Bulletin stone and Robertson counties and as far south as San Antonio. Along the line of the Houston and Texas Central Railway these clays are found about a mile east of Denny station in the banks of Grace Spring creek. They lie in a somewhat irregular form in association with a white sand, sometimes apparently underlying the sand, at other places interstratified with the sand, or lying in the form of a large lens within the sand. This clay and sand can be followed for more than a mile along the creek. At no place can this clay be said to have a uniform thickness. It varies from two to ten and some- times fifteen feet and at one or two localities the clay has a thickness of twenty feet. The clay is white with a very faint pinkish shade. The sands are white, very fine-grained, often indurated and carry numerous small scales of mica. In places it is stained with iron. South of this at a point five and one-half miles east of Bre- mond there is an occurrence of similar clay. "While the material is not classed as a high-grade china clay, still it is of a very refractory character. The physical proper- ties of the clay were as follows: Color when moist, whitish gray; soluble salts, 0.09 per cent. The material slakes fast and mixed up with 19.8 per cent of water to a mass of low. plasticity and very gritty feel. The air shrinkage was 4 per cent and the average tensile strength 48.5 pounds, per square inch with a maximum of 57.3 pounds. In burning it behaves as follows: Wet-molded Bricklets Cone Fire shrinkage 05 03 1 3 5 9 14 33 per cent 0.1 0.7 0.3 0.3 Color Absorption Whitish "White White White White White Whitish per cent 13.86 13.46 13.13 12.85 12.93 12.06 11.18 The material even at cone 14 (2570 F.) was not steel hard and in spite of its low shrinkage its absorption was not high. This clay was so sandy that the material did not lend itself readily to dry pressing. It does not burn to the pure white The Geology of East Texas 343 necessary for porcelain manufacture. The chemical composi- tion indicates the siliceous character of the clay and cause of its low shrinkage. Per cent Silica 83 Alumina 7.4a Ferric Oxide 0.36 Lime ; . trace Magnesia 3.01 Soda 1.26 Potash 0.30 Titanic acid 0.70 "Walter 3.70 99.75 Total fluxes 4.93 This is one of the most refractory of the Texas clays tested and is well worthy of careful investigation by fire brick man- ufacturers. Very little use has ever been made of this clay. A number of years ago Mr. Denny used it for the manufacture of common jugs and other pottery ware which he burned in a small down draft circular kiln close to the railroad. The ware burned hard and of a grayish color and readily took both the Albany black slip and salt glaze. Although this kiln is still standing, no ware has been made for several years. In the vicinity of Headville in Kobertson county there are several exposures of brownish colored and white clays. The whites are somewhat sandy and in places iron stained by the presence of ferruginous nodules. In places these white clays are overlain by a white sand. The deposits are irregular in thickness, varying from five to fifteen feet. On the J. W. Harper tract the thickness exposed is about five feet, but Mr. Harper says when burning brick in this locality he found the clay to extend downward below fifteen feet. On the Harper farm the white clay is overlain by a reddish sand. The areal extent of the clay in the Headville region was not ascertained, but from its appearance in a number of small 344 University of Texas Bulletin creeks it apparently covers several hundred acres, or at least enough to justify its exploitation. This material v^hen moist is brownish gray in color and slakes slowly when thrown into water. It has 0.15' per cent soluble salts and some fine grit. When mixed with 19.8 per cent of water it gave a mass which was highly plastic to the feel, but which had a low air shrinkage and tensile strength. The former was 4 per cent and the latter averaged 64 pounds with a maximum of 70 pounds per square inch. In burning the clay behaved as follows: Wet-molded Bricklets Cone: 05 03 1 3 5 9 14 30 Fire shrinkage per cent 17 4 6 1.4 2 3 Color Whitish Whitish Whitish Whitish Light-Bufe Whitish Whitish BuS Absorption 17.20 17.18 15.97 15.82 13.83 11.92 10.71 The chemical composition of this clay is: Per cent Silica 70.82 Alumina • ■ 18.90 Ferric oxide ' 0.40 Lime trace Magnesia trace Soda : 0.50 Potash .trace I'ltanic acid - 2.10 Water • . , .' 6.80 99.52 Total Fluxes 0.90 Eegarding this clay Hies" s'ays: "This is rather an inter- esting clay and while it is a fair grade of fi're clay, it is not highly refractory, due to its high silica percentage, and no doubt also due in part to the high percentage of titanic acid." The white clay belonging to this region and ttnderlying the brownish gray clays is in many respects similar to the cky The Geology of East Texas 345 found near Denny and belongs to tne same horizon. Ries classes it as a very lean sandy clay whose physical properties were as follows: Color, when moist, white; soluble salts 0.08 per cent; water required 17.6 per cent, slakes fast; plasticity low, with much coarse grit. The air shrinkage of the molded brieklets was 3.3 per cent and the average tensile strength 40 pounds, with a maximum of 46 pounds per square inch. In burning it behaves as follows: i Cone: 05 03 1 3 5 9 31 32 ii'ire sbinkage per cent 0.1 0.3 vis. Color, Pinkish Plnlcish Pinkish Pinkish white white white white Absorption, per cenit, 14.71 14.71 14.16 13.06 13.05 12.29 The chemical composition is: Per cent Silica 77.4 Alumina 15.7 Ferric oxide 0.7 Lime • -trace Magensla Soda ,. trace Potash trace Titanic acid 0.7 Water 5.7 lOO.Z Total Fluxes 0.7 The clay burns to a good white color, and is very lean and sandy, but if it were to be used for pottery manufacture it would have to be mixed with a denser clay. It is to be classed as a fair grade of fire clay and if some of the sandy matter could be washed out of it, the refractoriness would undoubt- edly be increased This clay, together with the brownish gray clay, was used for pottery and brick making a great many years ago. It will be noted that all the analyses given are those of the raw clays, that is, the clays just as they came from the mine, without any preparation of any kind. The effects of careful 23-ET. 346 University of Texas Bulletin washing or of mixing different clays to obtain material for special industries is practically unknown. At one time parties interested in the HeadviUe clay made an effort to secure its utilization. Some of the clay was mined and washed and sent to France where it was made into table- ware which was apparently of very good quality. ' At that time, however, the cost of preparation and transportation to potteries proved to be too great to warrant an attempt to open it up commercially. These clays are well worth a very thorough investigation. Their refractory character is fully established and there is a strong possibility that they can be prepared for use in the manufacture of the better class of white earthenware. These clays are also found in the Lignitie beds in the eastern portion of the State and may occur in Shelby county. While Walker does not mention the clays he speaks of the beds of white sand five and one-half miles north of Timpson. This would be about the proper horizon and it may be they will be found there. POTTERY CLAYS. These include clays suitable for the manufacture of porcelain and white earthenware such as may possibly be found in the beds already described as well as those for stoneware and common red earthenware. Stoneware clays of excellent quality abound in the Lignitie. The general character of the stoneware clays is shown in the following descriptions: On the north side of the railroad track at Saspamco a num- ber of openings have been made in order to obtain clay for the manufacture of sewer pipe for a factory located at this point. The material is similar to that used for stoneware man- ufacture at Blmendorf, and the formation involves a series of speckled shaly clays interstratified with occasional beds of sandstone and ochreous clay. Owing to the somewhat lentic- ular character of the clay deposits, new beds have to be opened from time to time as the old ones are worked out. .The sec- tion in the bank, which was being worked at the time of the writer's visit, was as follows: The Geology of East Texas 347 1. Sandy, laminated, iron-stained, surface clay 1 ft. 2. Chocolate clay .'. i 8 It. 3. Yellow, ferruginous clay (rejected) 1ft. 4. Chocolate clay of dense, tough character 7 ft. The beds dip gently to the westward and the. deposit whose section is here given can be followed for at least 1500 feet to the north, where it dies out. Lying to the northeast and west, respectively, are two other pockets of clay, and one large pocket near the works has been exhausted. The physical prop- erties of the sample taken from the pit in operation were as follows. Clay dense and homogeneous with a few mica scales. Color, when moist, brown; soluble salts; 0.24 per cent. The material slakes slowly and works up with 30.8 per cent of water to a mass of high plasticity and great stickiness, but little grit. The average tensile strength was 257 pounds per square inch, with a maximum of 310 pounds per square inch, but was found difScult to obtain a series of briquettes free from flaws, as the clay cracked some. The behavior of the material in burning was as follows : Wet-molded Bricklets Gone: 05 03 1 3 5 9 12 28 Fire shrinkage per cent 1.6 2.7 3.3 5.6 5.7 9.4 Swells vis. Color: Buff Buff Buff Buff Gray Gray Gray Absorption per cent 11.44 9.52' 6.57 2.35 2.83 0.82 Beyond Dry-press Bricklets Cone 1 » Fire shrinkage, per cent 2.75 8 Color Buff Buff Absorption, per cent • • 10.20 2 The clay burns steel hard at cone 05, and makes a good hard body of uniform color, which is buff, until cone 9, when it burned gray, due probably to reducing conditions. At cone 12 it swelled somewhat and was slightly blistered. It gives 348 University of Texas Bulletin good results when burned. iji dry press form. The chemical composition is as follows: Analyses of Pottery Clay from Saspamco, Bexar County : Per cent Silica 64.92 Alumina • ■ 22.70 Ferric Oxide > 0.80 Lime 0.10 Magnesia • • 0.74 Soda 0.71 Potasbi 0.12 Titanic Acid 1.40 Water 7.00 Total 98.49 Total Fluxes 2.47 The material is being used by the San Antonio Sewer Pipe and Manufacturing Company for the manufacture of sewer pipes, conduits and hollow blocks. They also utilize the clay for the manufacture of fire bricks for use at their own works. Denny, Falls County : The pottery clay used at this locality is obtained from a bed about three and a half iniles South of Denny. The clay bed, which has a thickness of 12 feet, is ex- posed for a distance of several hundred yards up and down the ravine from which the sample was taken, and is underlain by a white clay similar to that described from the vicinity of Bremond. The physical properties of the clay are as follows : The material, when moist, is of light brown color and quite homogeneous in texture. When dry it is very hard and slakes slowly when thrown into water. It shows but little grit, and contains 0.14 per cent of soluble salts. It required 24.2 per cent of water to mix it up to a mass of high plasticity, and had 6.3 per cent air shrinkage. The average tensile strength of the air-dried briquettes was 217 pounds per square inch, with a maximum of 251 pounds per square inch. It behaved as fol- lows in burning: The Geology of East Texas 349 Wet-molded Bricklets . Cone: 05 03 1 3 5 9 14 28 Fire shrinkage per cent 2 2 4 4.6 5 6.6 Beyond via. Color: Light Pink Buff Bute Gray Bute Buff Absorption, per cent 12.51 12.41 9.29 6.73 5.53 1.38 Dry-press Bricklets Cone • • 1 Fire shrinkage, per cent 4 Color BufE Absorption, per cent 12.25 This clay is not imlike the regular run of Texas pottery- clays. As it will be noticed, it burns buff to cone 9, when it burns gray. At cone 14 it swells and shows slight blister- ing as well as the development of a few fused specks of iron. Five miles east of Henderson, in Rusk county, is a pottery clay pit showing the following sections: 1. Gray sand 1 % ft. 2. Yellow clay 1% ft. 3. Pottery clay 4% ft. Parts of the pottery clay show some pockets of sand with slight variations in color. The color of the clay is similar to that used by Mr. Russell, whose pit is some four miles away, but it is not possible to say whether these two pits are different beds or parts of the same one ; but the clay here exposed in Mr. Hill 's pits is thought to be an extensive deposit. The physical properties of the material are as follows: Color, when moist, brown; soluble salts, 0.50; water required, 18.7; slaking, slow; plasticity, high; grit, very low; air shrinkage, 6 per cent; average tensile strength, 89.7 pounds per square inch; maximum 110.8 pounds per square inch. In burning it behaved as follows: 350 University of Texas Bulletin . Wet-molded Bricklets Cone: 05 03 1 3 5 9 14 27 Fire shrinkage per cent 2.3 2.4 4 5 5 6.3 7.3 vis. Color: Pink Pink Llglit Liglit Buff Butt Gray Buff Buff Absorption per cent 18.70 18.17 12.22 10.42 9.22 6.34 2.27 Dry-press Bricklets Cone 1 Fire slirinkage, per cent 3.38 Color Pink Buff Absorption, per cent 14.30 The wet-molded bricklets burn steel hard at cone 1, as did also the dry-press ones. The fire shrinkage of the clay, it will be noticed, is only medium and the clay is to be classed as a low grade fire clay. This, clay does not burn to as bright a buff as many of the pottery clays tested. That burned at cone 5 got flashed at one edge and showed a very much deeper color. Pottery clay is dug on the Henderson and Marshall dirt road, four aaid a half miles northeast of Henderson. The beds are at least 6 feet thick, but the base has not been exposed. The upper 1% feet is of reddish clay, but has considerable iron stain, which is pink when dry and blue when wet. Nothing definite can be stated regarding its extent. The physical qualities are as follows: The material is a hard, homogeneous clay, with a conehoidal fracture and some mica scales. It contains 0.06 per cent of soluble salts, and when thrown into water slakes slowly. With 29.7 per cent of water it works up to a mass of good plasticity containing a little fine grit. Its air shrinkage is 7 per cent and the average tensile strength 148 pounds per square inch, with a maximum of 177 pounds per square inch. In burning the material be- haved as follows: Tlie Geology of East Texas 351 Wet-molded Bricklets Cone: 05 03 1 3 5 9 14 Fire shrinkage per cent 1.7 2.6 4.3 4.7 6 6 6.6 Color: Pink Pink Pink Pink Pink Pink Gray Buff Bute BufE Buff Buff Buff 05 03 1 3 5 9 14 Absorption, 27 per cent 15.53 12.59 11.16 9.82 5.41 4.83 3.11 Dry-press Bricklets Cone: 1 9 Fire shrinkage 1.33 3.33 Color Pink Pink Absorption, per cent 7.53 ... The wet-molded-brieklets burned steel hard at cone 1. In its general features this clay closely resembles the Athens and the Denton pottery clays. The chemical composition is as follows : Aanlysis of Pottery Clay from near Henderson, Rusk county Per cent Silica 67.84 Alumina 21.80 Ferric Oxide 1.00 Lime trace Magnesia trace Soda ^ 1.11 Potash 0.39 Titanic Acid 1.48 Water ■ • 7.37 100.99 Total Fluxes 2.50 In the neighborhood of Evansville, Leon county, clays of economic value are found in association with the lignite de- posits. At various localities on the Connelly league and Rejon grant blue and gray clays occur which are of a refractory or semi-refractory nature and compare favorably with the clays 352 Vrdversity of Texas Bulletin used at Saspamco for the manufacture of sewer-pipe and drain- tile. These Evansville clays would take the necessary glaze. The Lignitic area of eastern Nacogdoches county, Shelby county, and the northern portions of San Augustine and Sabine will probably yield clays of similar character. The fact that certain clays are grouped here under the head of stoneware clays is not to be regarded as indicating that they can be used for this purpose alone, but the term is to be regarded as an index of certain physical qualities character- istic of stoneware clays. The most important use of stoneware clays is for the manu- facture of terra cotta, buff brick, floor tile, retorts, fire brick, in short, as an ingredient of many kinds of ware in which a refractory, plastic, more or less dense burning clay of good bonding power is required. Their value is never sufficiently high to permit of their ship- ment to distant markets, and consequently, tbey must be worked up near the point of production. The Texas stoneware clays have not, by any means, been developed to their full capacity, for at present they are utilized in the most limited manner by small potteries scattered here and there- over the State. The wares now being produced show that they can not only be made to yield a good stoneware body, but -vy^ill also take either a slip, salt or Bristol glaze- ware with good results. CliAYS OP THE MARINE The Marine is prevailingly sandy but carries some clays of economic importance. As has been stated previously, beds of lignite occur in it ocasionsially and these are accompanied by clays or clay shales of good quality, some of which are refractory and others, while not sufficiently refractorjr to be classed as fire clays, are well adapted for the manufacture of bufl brick. The deposits occurring at Minera in Webb county in connection with the cannel coal of that region are of this latter class. The de- posits worked near Nacogdoches are of the former. A stoneware clay is dug near Carmichael's pottery six miles south of Nacogdoches. The material is a dark brown, finely The Geology of East Texas 353 gritty clay, containing 0.10 per cent soluble salts. It slacks slowly, but with 25.3 per cent. water, works up to a mass of high plas- ticity whose air shrinkage was 9.6 per cent. The average tensile strength was 302 pounds per square inch, with a maximum of 374 pounds per square inch. In burning it behave as follows. Wet-molded Bricklets Cone: 05 03 1 3 5 9 14 Fire slirinkage, per cent 03 1 2.6 3 4 5.7 vis. Color: Bult Dark Deep Deep Gray Gray Gray Buff Buff Buff Buff Buft Absorption, per cent 10.35 8.63 5.68 5.32 3.30 4.00 I Dry-press Bricklets Cone : 1 9 Fire shrinkage, per cent 2.33 6 Color Buff Light Gray Absorption, per cent • ■ • • 14.50 4.86 The clay burned steel hard at cone 9, but was nearly so at cone 3; its fire shrinkage is low and it burns to a good d«nse body. The slight increase in absorption of the wet molded brick- let at once 9 is due to a slight blistering of the ware. The chemical composition of the sample tested is : Analysis of Pottery Clay from Nacogdoches, Nacogdoches County Per cent Silica 75.33 Alumina 14.73 Ferric Oxide . . ■• J .10 Lime • ; 0.05 Magnesia l-fil Soda 0.10 Potash 0.64 Titanic Acid 1.27 Water . . .' 4.50 Total : 99.33 Total Fluxes 3.50 354 University of Texas Bulletin This clay is at present used for making common stoneware. It burns to a deeper buff than the Athens stoneware clay. It is not sufficiently refractory to bfr used for fire brick manufacture, but could profitably be utilized for making buff brick, terra cotta, or at least for the backing of encaustic tile. CLAYS OF FAYIETTE AND YEGUA These formations both carry numerous beds of clay. Some of the clays of the Fayette are white in color and are of good plasticity. They have been called kaolins but are probably not entitled to such classification. They vary very much in character and the specimens analyzed by Ries supposedly from these beds are not thought to be of especial value. A sample of the so-called kaolin was tested from the property of Mr. Lytenburg, southeast of Lena. This material is whitish in color, but contains heavy limonite stains on all of the joint and fracture surfaces. It slakes very slowly when thrown into water and forms a gummy mass of very low plasticity, but practically free from grit. Its tensile strength is so low that it was difficult to test the briquettes made from the clay. The material was so lean and cracked so when drying that no wet-mud bricklets were tested and the sample burned were all molded dry-press. When burned at cone 9 a sample ground to 60 mesh showed a fire shrinkage of 8 per cent and absorption of 9.44 per cent. Another sample ground to 100 mesh and burned at this cone showed a fire shrinkage of 12 per cent. A third sample ground to 60 mesh and burned at cone 12 showed a fire shrinkage of 13.33 and an ab- sorption of .61. The clay burned steel hard at cone 9, and al- though its general color was whitish, all of the samples burned showed small black specks. The material is not a fire clay for at cone 27 it fuses to a clear glass. Its ■chemical composition was as follows : Per cent Silica 73.00 Alumina 15.79 Ferric Oxide 63 Limi ; 1.29 Magnesia 1.53 The Geology of East Texas 355 Soda 16 Potash. trace Titanic Acid 10 Manganese Dioxide ■ trace Water 5.76 Total 98.69 Total Fluxes 3.71 This is the only test of which we have record, and it should not be taken as characteristic of all Fayette deposits, for among them will be found clays of better grade than this. In the region under consideration the Fayette outcrop at Bomer in Angelina county may repay examination. This bed of clay is white to cream-colored, sometimes grayish when damp. It is hard, compact, fine-grained and breaks with a conchoidal fracture. Sections of four to five feet were found with bottom not seen. It appears to be a lenticular deposit with an east-west diameter of 2,000 feet or more. A commercial an- alysis gave the percentages of silica 64.85, alumina 17.01, with about 6 per cent of fluxing material. The shales and clays accompanying the lignites of the Tegua should yield some fair beds of plastic or semi-refractory clays but so far they have not been studied nor are there any localities within the area at which they have been utilized. CliAYS OF THE JACKSON While we have no analyses of clays belonging to the Jackson, there are beds occurring in the Caddell series which are appar- ently of good quality for the manufacture of bricks and common earthenware. Among, the clays of the upper portion of the Jack- son some of those which have been derived from the alteration of the sediments of volcanic origin will furnish good slip clay ma- terial and this is also true of similar clays in the Corrigan. Ries gives the analyses of one of .these. Two miles southeast of Carmona and 8 miles east of Corrigan clay is found outcropping for a distance of some five hundred feet on the bank of Bull Creek on the property of the Cameron Lumber Company. The thickness exposed is at least six feet but the base of the bed is hidden. The clay, when moist, is of a 356 University of Texas Bulletin sky blue tint and very uniform color, but when dried is almost white. It appears to be slightly granular in texture, but is soft and can be easily crushed between the fingers. A sample of this clay was tested with the following results : Soluble salts, 0.06 per cent; water required, 36.3 per cent; slaking fast; plas- ticity, low; texture, sandy. The air shrinkage is 1.3 per cent and the average tensile strength 61 pounds, with a maximum of 62 pounds per square inch. Analysis of Clay from Carmona, Polk County: Per cent Silica 68.34 Alumina 15.i!ii Ferric Oxide ii.44 Lime ■ • 1.20 Magnesia 0.88 Soda 3.55 Potash 2.47 Titanic Acid 0.52 Water . . • ■ 4.70 Total 100.38 To;al Fluxes 11.54 Among the peculiar physical characteristics which the clay shows are its low air shrinkage and its remarkably high fire shrinkage, which at cone 1 is 16 per cent. It has no value what- ever as a brick clay and its chief use would be as a slip clay for decorating pottery. Clays of this character are rather common in both the Jackson and Corrigan of our area and they also occur in the Fayette west of the Colorado. Kennedy says of a clay of this character from Grimes county : An extensive deposit of a good clay occurs in the neighborhood of Piedmont Springs. In structure it is thinly stratified and breaks with a sub-eonchoidal fracture. Thin streaks or stains of iron occur at places throughout the partings, but in general the clay' is milky white. An analysis in the laboratory of the Survey shows : The Geology of East Texas 357 Per cent Silica 58.50 Alumina 18.39 76.89 Ferric oxide ■■.•... 3.21 Lime ii.34 Magnesia 1.61 Potash 2.70 Soda 4.93 Sulphuric acid trace 14.79 Water and loss 8.70 8.70 Specific gravity, 1.5 100.38 The high percentage of the alkalies, iron, lime and magnesia contained in this clay places it in the anomalous position of midway between the grade of a good pottery clay and a ' ' slip ' ' clay. It might probably, with care, be utilized for certain grades of earthenware. In composition the Piedmont clay re- sembles the "Albany" slip so much used among the pottery manufacturers for glazing purposes. CLAYS OF THE FLEMING The prevalence of calcareous material in the Fleming clays is against their use as fictile material but there are oecasi9nal deposits of value. A sample of clay from the land of U. R. Shine, Hortense, Polk County, had the following physical properties: Color, pinknbrown; soluble salts, 0.15 per cent. It contains very little grit and works up with 30 per cent of water to a mass of high plasticity, whose air shrinkage is 8.1 per cent. The average tensile strength of the air-dried briquettes was 248.5 pounds with a maximum of 269.5 pounds per square inch. Its burning qualities were as follows: Wet-molded Brichl&ts Cone: 05 1 3 5 9 Fire shrinkage, per cent Color: Absorption, per cent 12.37 9.35 7.96 4.25 2.33 2.6 4.3 5.3 6.7 8 Pink Pink Gray- Gray Gray Brown Brown 358 University of Texas Bulletin Its chemical composition was as follows: Analysis of Clay from Hortense, Polk County. Per cent Silica 70.00 Alumina 18.60 Ferric Oxide 4-50 Lime trace Magnesia ' trace Soda 0.90 Potash *race Titanic Acid >• 0-60 "Water 6.10 Total 100.70 Total Fluxes 5.40 Although this is a rather siliceous clay, as shown by the physical properties and the chemical analysis, still it bums to a rather dense body and becomes steel hard even at cone 1. At the present time it is not being worked for any purpose, but would, no doubt, lend itself to the manufacture of com- mon brick, or even, perhaps, dry-press brick, and is less sili- ceous than some clays which are being used in the State for molding in dry-press machines. There is a possibility that some of the more highly calcareous clays of the Fleming would furnish material for the manufac- ture of natural cement. 1 An analysis of clay of this character from near Courtney in Grimes county shows: Per Cent Silica 40.69 Alumina 12.68 Ferric Oxide 3.90 Lime 18.12 Carbonic acid gas and water 18.91 Alkalies Dy difference 1.14 Magnesia .92 Manganese trace Water at 100 degrees C 3.64 100.00 The Geology of East Texas 359 At many localities within this area there are deposits of clays suitable for the manufacture of red brick and pressed brick some of which are being utilized by local brick yards. Taken all together, therefore, the clay resources of the area appear to be ample for a great production of common brick, pressed brick and fire brick, common red earthenware and stoneware, sewer-pipe, drain-tile, encaustic tile and, in short, practically all clay products below the grade of white earthen- ware with a possibility of some clays suited for that use. CHAPTER XVI. FULLER'S EARTH, VOLCANIC ASH, GLASS SAND FULLERS EARTH Fuller's earth is a material having a chemical constitution similar to that of clay, but differing from ordinary clays in some of its physical properties. It possesses a high absorbent power for certain substances and by reason of this is very useful as a decolorizing agent. Its chief use is for filtering, bleaching and clarifying fats, greases and oils. The value of any deposit for these purposes cannot be determined by chem- ical analyses, but must be ascertained by practical test. To be' of commercial importance, the fuller's earth must not only bleach the substance treated, but it must leave no disagreeable taste or odor, must not absorb too much oil, must filter well and without cloggin'g filter press. Fuller's earth that gives excellent results with one class of fats or oils may be far less satisfactory with others, and that which is used for bleaching petroleum oils is seldom the best bleaching and clarifying agent for use with vegetable and animal oils. To fit fuller's earth for use it must be prepared by drying and grinding to the size best suited to that use. In preceding chapters attention was called to the prevalence of volcanic ash or tuff and fuller 's earth in the upper portion of the Jackson and the Corrigan throughout the region be- tween the Neches and the Brazos. The deposits are at times very closely associated and constitute a considerable portion of the deposits of the formations named. It is probable that the fuller's earth is simply altered portions of the ash or tuff. The relations of the volcanic ash or tuff and fuller's earth are shown by the occurrence on Lucas creek north of San An- tonio, where there is a bluff 18 feet in height, of which the lower 8 feet are fuller's earth and the upper 10 feet rhyolitic tuff or ash. There is a little selenite near the border line be- tween the two. Similar occurrences were noted south of Cor- The Geology of East Texas 361 rigan, the fuller's earth being found in one or two instances overlj'ing the ash instead ot beneath it. In color, the fuller's earth of this region varies from a creamy white to yellow, brown and gray. Some typical exposures of fuller's earth occur in the vicinity of Corrigan and Moscow. About 1% miles southwest of Corrigan along Bear Creek, there is exposed a bed of fuller's earth. The section along the creek is as follows: 1. Light-brown or drab colored plastic fuller's earth. Thin- bedded 4 % ft. 2. White, fine-grained volcanic ash made up of minute white grains 3 in. 3. Greenish brown, structureless gypsiferous clays, weathering yellow 3% ft. If this fuller's earth proves to be of good quality, the de- posit could be easily worked. A hill section one-fourth mile west of Moscow Station on the Trinity road shows fine, loose, imperfectly laminated clay, light to dark cream colored on surface exposures, but grayish to greenish-drab underneath. The layei-s which show the laminations are creamy white, non-plastic, clay and may pos- sibly be fuller's earth. The following is the section from bottom up: 1. Light gray to light green drab clay 3 ft. 2. Creamy white non-gritty laminated fuller's earth 1 % ft. 3. Clay like No. 1 % ft. 4. Pine and laminated cross-bedded light yellow clayey sand weathering whitish to light-blue and with very thin seams of whitish clay 3 % ft. 5. Fuller's earth like No. 2, becoming more gritty towards the top where it has white limestone nodules • 10 ft. 6. Light green clay with large and small calcareous nodules. A number of other' occurrences are noted in the description of the stratigraphy of the Jackson, Corrigan and 'Fleming We have no record of any of these earths having been util- ized commercially to any extent, but with the great number of 24- ET. 362 University of Texas Bulletin refineries so near them it would seem advisable to have the various localities studied and the material carefully tested. VOLCANIC ASH Volcanic ash is used as a polishing powder and in the man- ufacture of scouring soaps. Deposits of this material of considerable thickness are found throughout the region between the Neches and the Brazos in the Jackson and Corrigan and probably in the Fleming. In the Jackson there are two or more beds which are trace- able for a long distance and which are excellent horizon markers. In the other formations the deposits are more local in their nature, but taken as a whole form a considerable part of the sediments composing them. Many of these occurrences have been referred to in the description of the stratigraphy of the region. Some of the other localities mentioned by Baker and Suman are Sulphur Springs, five miles north of Chester in .Tyler county, where there is a six foot bed of white volcanic ash; Chalk Bluff, northeastern Polk county, where there is an ex- posure of 8 feet of thin-bedded, medium grained volcanic ash. Around Potomac, Polk county, there are deposits of volcanic ash five feet and more in thickness. The ash is pure white in color and of very fine even grain. It also occurs at Groveton, where it contains pellets of cream-colored, non-plastic clay, probably fuller's earth. This bed of ash is cream-colored and pink. Kennedy, under the term "siliceous sinter," describes the various deposits of ash of the Piedmont Springs area in Grimes county: "In Grimes county these deposits are best developed in the neighborhood of Piedmont Springs. Small outcrops of sinter occur at Kellum Springs and on Mr. S. Smith's land, about two miles east of Union Hill. In the Piedmont Springs area the deposits consist of light gray sands, with great quantities of beautifully opalized wood, sandy clays, white thinly lami- The Geology of East Texas 363 nated fine-grained clay, and extensive irregularly shaped de- posits of siliceous sinter. A section close to the springs shows : 1. Light gray sand 5 ft. 2. Light gray or pinkish gray sandy clay 2 ft. On the C. 0. Edwards headright, and about a mile northeast of the springs, another section shows: 1. Gray sand ., 1 ft. 2. Thinly laminated yellow and brown sands 5 ft. 3. Pine-grained laminated white clay 4 ft. The surface of the country in this region is covered with grayish white or light gray sands, containing bowlders of coarse-grained flaky siliceous sinter and great quantities of opalized wood of different colors. While the greater portion of the pieces of opalized wood are small, many of them measure from four to eight feet in length and from one to three feet in diameter. These large trunks are very easily broken, and break with a glassy fracture, although longitudinal sections of from two to four feet are easily obtained. Two miles west of the springs, deposits of a very fine-grained siliceous sinter occur upon the southwest corner of the James Tuttle league and on the W. P. Zuber headright. A section on the Tuttle league shows: 1. Coarse gravel Scattering. 2. Dark gray sandy soil 1 % ft. 3. Siliceous sinter 4 to 5 ft. This deposit of sinter underlies an area of from twenty-five to thirty acres. On the west side of the same league, and about a mile farther west of this deposit, the bank of a small creek running into Dry branch shows a section of: 1. Gray surface sand with small quantities of pebbles 4 ft. 2. Soft fine-grained sand 10 ft. 3. Broken laminated bluish gray clay 3 ft. 4. Lignite 3 ft. 364 Vniversity of Texas Bulletin Southwest of the siliceous sinter deposits of the Tuttle league there is another deposit of the same class of material on the W. P. Zuber headright. The sinter in this area occurs in all the creeks and washouts along the east side of the headright, and is overlain by a. light gray sand and gravel made up of pebbles of quartz and jasper, and underlain by a gray sand, as seen in the following section: 1. Light gray sand and gravel, the gravel scattering 2 to 5 ft. 2. Siliceous sinter 4 to 5 ft. 3. Gray sand, visible 2 to 6 ft. Two miles east of Piedmont Springs a cutting on the east side of Sandy creek shows a section of: 1. Gray-sand with white opalized wood 3 to 5 ft, 2. Thinly laminated gray sandy clay 2 to 6 ft. Going northward to Kellum Springs deposits of siliceous sinter occur on the Wm. Pitzgibbon league, and one mile west of the spring the following section occurs in Chalk branch, a small stream tributary to Gibbon's creek: 1. Gray sand 1 ft. 2. Lignitic sands and clays 5 to 12 ft. 3. Siliceous sinter 2 ft. 4. White sand 1 ft. 5. Brown lignitic sandy clay. In this region the sinter lies in thin strata or seams between deposits of a coarse white sand, which rests upon a laminated brown sand. The section shown for nearly a mile southward along the creek is a succession of lignitic sands and clays, alter- nately dipping southeast and northwest. , These ligfiitic de- posits overlie the siliceous deposits. This siliceous sinter, which is locally known as chalk, is reported as occurring in small quantities at other places in this region and in the area between Piedmont and Kellum Springs. Five miles northeast of Kellum Springs, on a Mr. S. Smith's The Geology of East Texas 365 land, near Union Hill church, there is an isolated deposit of siliceous sinter covering an area of nearly ten acres and having a thickness of over twenty feet. The greater portion of this de- posit is covered by a dark gray sandy soil, and gray sands form the prevailing characteristic of the surface of the whole surrounding country. Nowhere throughout the area occupied by these beds can the thickness of the deposits belonging to the Piedmont Springs group exceed thirty feet. On the northeastern border the gray sands and sinters either rest upon or are interstratified with the lignitic deposits; and toward the southwest, in the neighborhood of Piedmont, where they attain their greatest Thickness, wells dug to a depth of thirty feet pass completely through these beds and enter blue clays containing thin seams of an earthy brown coal. The siliceous sinter found in these deposits is a very fine- grained, soft, pulverulent, snow-white mass, amorphous in places and showing lines of stratification in others. It has a .specific gravity of 2. Under the microscope the grains are small, rounded, and angular, generally flattened and scaly, and all translucent, some of them being perfectly transparent. Many of the scales are striated and marked in such a manner as to resemble thin sections of the opalized wood. GLASS SANDS Sands for the manufacture of glass, especially that of higher grade, must be practically free of impurities. Iron oxide, even in small quantities, colors the glass green and any ad- mixture of clay tends to cloud it. Even sands of pure white color are sometimes not sufficiently pure for this use without washing. The glass sands of East Texas are found in two horizons. The lower, geologically, are the white sands that come in con- nection with the gray refractory clays occurring above the middle of the Ligjiitic, and these have been reported both from the eastern and western portions of this area. The upper deposits are of Pleistocene age and occur in the drainage areas of Trinity and San Jacinto rivers. The Pleistocene sa^ds are 366 University of Texas Bulletin derived from the disintegration of the rice sands of the Cor- rigan. SANDS OF THE LIGNITIC In Shelby county, Walker calls attention to a pure white sandstone at Cave Spring 5% miles north of Timpson. TMs is a soft friable sandstone, in places stained with iron, but when washed as in the neighborhood of the spring, of pure white color and apparently well suited for glass making. Similar sands were noted at several localities to the north of this in Panola county, among which were a creek crossing one and one half miles northwest of Beckville on the Harmony road and Grand Bluff on the Sabine river. This sand is also found three miles north of Jacksonville in Cherokee county as a pure white siliceous sand. Along the lines of the Houston and Texas Central Railroad sands of the same character ar'e found from Dennys to Head- ville and with small preparation will yield glass sands of ex- cellent quality. SANDS OF PLEISTOCENE In the drainage valleys of the Trinity and San Jacinto rivers south of the belt occupied by the deposits of the Corri- gan there are numerous bars and banks of a pure white sand derived from the disintegration of the rice sands of that forma- tion; These are good glass sands and can be had in abundance at or rtear the railway crossings on these streams. Chapter XVII BUILDING STONE AND GRAVEL STONE Building stone is relatively scarce in our East Texas area and the only stone of value is sandstone, of which there are two classes. Brown sandstones which are altered glauconitic sands or sands cemented by ferruginous cement. Gray sandstones with calcareous or siliceous cement. The brown sandstones are found almost entirely in connection with the Marine beds. In some places the altered greensands are of sufScient hardness to be quarried and are used occasionally where other rock is scarce for building foundations and chimneys. At other places the sand beds have been cemented by ferruginous solutions and hardened into good beds of sandstone. The gray sandstones are by far the most abundant and are found in Fayette, Jackson and Cbrrigan. Some of them have a calcareous cement, but probably the greater part have a si- liceous matrix. No limestones suitable for building are known in the area. SANDSTONE OP THE MARINE — BROWN SANDSTONE The most important of these sandstones are a series of local and limited deposits formed by the action of ferruginous solutions on the original loose sands. This varies from a comparatively soft friable mass to a compact hard and flinty rock ; from yellow to very dark brown in color, and from one to twenty feet thick. Such rocks are found everywhere throughout the East Texas re- gion, and are often used for foundations and chimneys. They occur plentifully in the bluffs of the Angelina at the mouth of Walker creek, and on the Neehes river west of Gent, in the shape of a soft friable sandstone. The State Penitentiary at Eusk is built of a soft yellow sandstone, containing specks of altered glauponite and a few casts of fossils. This was obtained from a 368 University of Texas Bulletin bed ten feet thick immediately underlying the main iron-bearing greensand bed It is soft and easily cut with a saw. A rock very similar to this is found capping Cook's Mountain, three miles west of Crockett, in Houston county. It is friable sand- stone, and composed of siliceous sand with specks of glauconite and mica, is of a yellow color, contains many fossil casts in places, and shows considerable cross-bedding. The greensand bed which directly underlies the brown lami- nated iron ore stratum has often become yellow and hardened to a sufficient degree to be utilized as a building stone. In the re- gion where it occurs it is very extensively used for 'fireplaces and such small structures. It is of a chalky or waxy consistency, dense and compact in structure, and easily shaped into the desired form by an ax or saw. On account of the ease with which it can be cut, and also a certain toughness which it preserves in spite of its softness depends its universal use wherever it can be found. The greensand bed varies from thirty to forty feet thick, but it is only in parts of it that he hardening process has gone on to a sufficient extent to make it available for building pur- poses. These indurated places vary from one to ten feet thick. Sometimes the greensand has become hardened without losing its green color, and in such cases we have a green rock of very sim- ilar nature to the yellow one just described. Such material is found in Doyle's Gap and on the slope of the Mount Selman iron range, in Cherokee county. The glauconite in this green rock is generally mixed with a large amount of clay of the same color, and in some places the clay almost entirely replaces that mineral. This presence of clay probably accounts for the hard- ening of the bed as it has acted as a cement in indurating the glauconite. Sometimes, also, finely disseminated carbonate of lime is the cementing material in such rock. These sandstones, although soft when first quarried, have a tendency to harden when exposed to the weather and are very durable, although they will not admit of fine dressing. The building stones of Robertson county are wholly of brown sandstone, and occur in many locations along the ridges extend- ing across the country from the Houston and Texas Central Rail- way eastward. They are rather coarse-grained, and contain fre- The Geology of East Texas 369 quent streaks or pockets of coarse sand or fine gravel in the form of a conglomerate. The sandstones found along the top of the ridge on the Den- ver Jones headlight form a bed from two to four fee,t in thick- ness, and have been quarried for railway purposes, having been used as piers and abutments of bridges on the line of the Houston and Texas Central Railway. In the neighborhood of Franklin the hills near the town and surrounding Racetrack prairie contain soft brown sandstones, which may be utilized for building purposes They also occur to the west of the town, and at several other places in the central portion of the county. These sandstones are quarried only as needed and no regular quarries have been opened in them. SANDSTONE OF THE FAYDETTE Southeast of Alto in Cherokee county a hill at Huston Park 75 feet in height has in the upper 60 feet a hard cream colored sandstone. It is fine-grained and in places approaches a quartz- ite in texture. It weathers irregularly with fretted forms. The outcrop of this rock extends a mile east of Huston Park and as far to the south. Penrose states that properly quarried it will be a valuable stone. The Fayette areas along the Houston, East and West Texas Railway north of Burke show similar sandstone. It is all fine- grained, some of it is laminated and it varies in hardness. A fine grade of light gray sandstone of medium grain occurs east of Blix on Jack creek in the Lavinge survey, Angelina county. It is of medium hardness and in layers of about one foot in thickness. To the west of the creek it outcrops in a ridge ten to twenty feet high and a well fifty feet deep was in sandstone throughout. In the Fayette at Huntington a small hill on the Renf ro place is composed of a very hard sandstone, almost a pure quartzite in places, breaking with splintery fracture. Similar sandstones occur near Homer where it was formerly quarried and used for lining walls and building chimneys and foundations. The quantity however is small as it is at Hunt- ington. 370 University of Texas Bulletin SANDSTONES OF THE JACKSON Sandstones of good quality are found in places in the Jackson area. No attempt will be made to enumerate them but of some those which came more directly under our notice will be described. On the sides and top of the low hill 1/4 mile east of Manning is found a coarse-grained medium-hard, light gray sandstone in layers averaging about one foot in thickness. The cement is whitish and granular. The sandstone overlies the flaggy shaly beds which outcrop in the town of Manning. This stone could be readily dressed. Three miles south of Manning, east and west of the Carter- Kelly lumber tram there outcrops along the tops of the lower ridges and in the middle slopes of the higher hills, a white, fine- grained, well indurated and rather heavy bedded sandstone. Several holes have been blasted in the vicinity. The rock is of good quality, but its thickness could not be determined. The harder rock is underlain by soft sandstones and arenaceous clays. About three and one-half miles slightly north of east of Po- tomac, near the southern line of the W. B. Hardin Survey, on the farm of Mr. Barch, is a ridge trending in a general east-west direction, capped by a hard dark gray quartzite outcropping in rough irregular blocks. This rock has a splintery to conchoidal fracture and should be admirably adapted for use as crushed rock in concrete work. The ridge was followed for % of a mile with continuous outcrop of sandstone. The thickness was indeter- minable. Near the line between Section 40, International & Great North- ern Railroad land and the Rains Survey, some two miles west of the Houston, East and West Texas Railway is an outcrop of fine-grained, fairly resistant sandstone. There is a thickness of 12 feet along a hillside and quarrying here would be a very simple matter. While this rock might possibly be a little soft for building purposes, it might be of use for ballast. A hill seventy feet in height with a summit area of two and one-half to three acres is found in the bottom of Dean Creek, Trinity county. The creek bows along the northern and north- The Geology of East Texas 371 eastern base of this hill. In the bed and banks of the creek ia found the following section, detailed from the base upwards ; 1. Base, dark brown carbonaceous clay, total thickness unknown. 2. Lignite, poor in quality 1 ft. 3. Dark brown carbonaceous clay, gradually becoming lighter with a lessening in the amount of carbonaceous matter toward the top 1 ft 4. (a) At the north along the creek banks is exposed 10 feet ^ of thinly laminated light-brown to drab sandy clay carry- ing plant fragments. The bedding is not very regular and the individual beds are not lof uniform thickness. At the easternmost locality examined the beds dipped 3 % " to the southward, 50 yards south the dip is 8° to the southward, while 100 yards south of the latter locality, the dip is ap- parently 4 or 5° to the westward, but this apparent dip may have been caused by slumping. 4. (b) At the south, directly under the northeast base of the hill, there is 12 feet of thinly laminated brownish to buff sand carrying thin streaks of brown carbonaceous material, but becoming sandier and thicker bedded towards the top. The bedding here is also slightly irregular. Above the bed 4 (b) the surface of the hillside is strewn with blocks of sandstone. A rim of sandstone in place surrounding the top of the hill is in places a massive bed three to four feet thick. Locally these sandstone blocks are quartzitic; in places they exhibit imperfect lamination and break in blocks thick enough to be suitable for dimension stone. The rock last de- scribed splits readily along the bedding planes and could easily be shaped into rectangular blocks. In texture the sandstone is medium-grained. It contains thin flakes of selenite and much of it case-hardens on the surface on exposure to air. This property of ease-hardening is a valuable one in building stone of this kind, since the stone in the quarry is soft enough to be readily cut and shaped, and it becomes harder after removal from the quarry. All of the rock seen is suitable for crushed stone of a very fair quality. Near the east corner of the John Veatch grant, approximately two miles north of Groveton, the sandstone outcrops on the north- west side of a hill. There is a vertical thickness of 30 feet in which the rock is found. At the base of this thirty feet, hard 372 University of Texas Bulletin rock is found in place in layers varying from six inches to a foot in thickness. Above this outcrop hard sandstone blocks are found on the side and top of the hill, although no other ex- posures of rock actually in place were noted, save that mentioned above. The sandstone as* a whole varies in degree of hardness from a fairly hard rock, breaking with clean fracture, to a hard gray-blue silica-cemented rock which is really a quartzite. This quartzite is hard, compact, and brittle, and breaks into angular fragments. The softer varieties of rock vary from light brown to buff in color. Some of the reck is irregularly stained a brown- ish color with limonite. The rock contains small irregular flakes of selenite. All of the rock seen in this hill is suitable for crushed rock and some of it which lies in layers of ten inches and upwards in thickness is suitable for building stone. The blue- gray quartzite, with its pleasing color and great crushing strength would be especially suitable for building stone. West of the Trinity the sandstones of the Welborn division will probably furnish some good building material. In Grimes county, the hard, semi-quartzitic and close-grained . sandstones occur only in the north central portion of the county, where they appear as a narrow belt, extending from the L. J. P. Mammel headright northeasterly to the northwest corner of the Biggam White headright, and from this latter thin beds extend north and easterly to within a few miles south of Bedias post- ofiSee, on the D. S. Stone headright. They are best developed on the Biggam White headright, where they are repesented by a ledge from fifteen to twenty feet high. The rocks forming this ledge are stratified and lie in strata from six to eighteen inches in thicness, and change fom a soft gray colored to a hard gray and brownish gray colored sandstone, with occasional blocks showing the characteristic texture of quartzite. Some of the beds are very much broken and tilted in places, and lie mostly in the shape of boulders or blocks, many of them measuring from eight to ten feet in length and nearly as many feet in width. On the Mammel headright the same class of rocks occur along the northern edge of the Gibbons creek bottom lands. Here they lie in a very similar condition to that on the Biggam White land although the blocks are more irregularly formed and much smaller and are of less value as a building material. The Geology of East Texas 373 Intermediate between these exposures the rocks belonging to this group are white and grayish white, evenly bedded, close- grained sandstones. This class occurs in quantities along the Upper division of Rock creek on the John Bowman headright. Another deposit is found in the Francis Holland headright, about a mile south of Anderson, on the Anderson and Navasota public road. These rocks lie close to and appear on the surface in many places. They have been quarried both on Rock creek and in the neighborhood of Anderson, and from the smoothness of their grain and closeness of texture admit of being dressed in a fairly good condition, although somewhat limited as to size. The stone 'finishings of the court house at Anderson are from the quarry south of that place. The building stones of Brazos county are almost altogether confined to the hard gray sandstones of the Wellborn beds. Small deposits of a coarse, soft, brown colored sandstone occur on the McMillan and Williams headright, about four miles west of Bryan, but these deposits are of comparatively little value. Isolated patches of gray sandstone occur on the James Hope league, and on the Sam Davidson league much larger deposits occur. These have been quarried in the neighborhood of Well- born and Minter Springs for .building purposes. In the Rock prairie region, on the Stephenson and Robertson leagues, as well as on the N. Clampett headright, deposits of a close-grained, fi:rm sandstone occur, which can be obtained in blocks of large size and admit of fine dressing. A quarry on the N. Clampett headright supplied the foundation stones for some of the Agricultural and Mechanical College buildings a number of years ago. SANDSTONE OF THE OORRIGAN These are the beds best known of all the Bast Texas sandstones as the5^ furnished much of the material for the harbor improve- ments at Galveston and Sabine Pass and are now being worked to supply crushed rock for concrete work throughout South Texas. These sandstones are of various degrees of hardness, many of them being hard compact quartzites but the degree of induration 374 University of Texas Bulletin varies very, much locally. Some strongly indurated sandstones have a white porcellaneous matrix while in others, which are less indurated, the cementing material, while white, is not lustrous. The deposits of the Neches river drainage, southern Angelina and northern Polk, Tyler and Jasper counties, are those which have received most attention. Two miles west of Aldridge in northern Jasper county Kyle'i Quarry in the Conn league has been opened on a deposit of the Corrigan sandstone. This quarry is in the quartzitic phase of the Corrigan with local lenses of greenish clay. 'The main layer quarried is from 35 to 40 feet thick, but the superficial 10 feet is not indurated enough to produce crushed rock. The rock worked has hackly fracture with sharp edges. It is suitable only for rough masonry or for crushed rock. There is 10 to 12 feet of Lafayette over- burden to be removed. The hard rock is very light gray or gray blue in color. It con- tains angular fragments of hard whitish and greenish clays. The rock is made up mainly of quartz and chert, sometimes coarse enough to be conglomeratic, with a porcellaneous to translucent cement. Some specimens show an outside film of porcellaneous ce- ment which is about % inch thick, the interior of the rock being quartzitic, suggesting that the porcellaneous surface film may possibly be an alteration of the quartzitic interior. The inter- bedded lenticular clays are sulphurous. About two miles southwest of Rockland there outcrops on the sides of a large hill a porcellaneous-cemented sandstone showing a high degree of induration, and in places being a fine quartzite. A vertical thickness of 10 feet was exposed. The same rock again outcrops about % mile west of this place. To the west of the point where the Carter-Kelley Lumber Company tram crosses the Neches river, along the southern bank, a series of high bluffs rise above the river. They ex- posed at the top and well down the sides a medium to doarse- grained sandstone having a porcellaneous matrix. Underlying is a white, somewhat arenaceous claystone of various degrees of induration. The sandstone is in places indurated to a quartzite and would make a good rock for concrete work. The Geology of East Texas 375 Near Mt. Hope church, some 2^^ miles north of Chester an exceedingly well indurated fine-grained sandstone, showing a splintery fracture wherever broken into, outcrops over an area approximately eight to ten acres, and along a bluff overlooking Russell creek. This quartzite is at least eighteen feet thick, as shown in outcrop along the public road. It is underlain by a clay, weathering cream colored. At Griswold, three quarters of a mile west of Stryker on the Missouri, Kansas and Texas Railroad, a spur turns off south for the quarry of the Texas Grading Company. A ridge of sandstone commences near the Missouri, Kansas and Texas track and continues south along McManus Creek for nearly a mile. The rock in the northern end of the quarry is a soft to medium hard coarse-grained, gray to light brown sand- stone, for the most part massive but locally showing up as cross-bedded. The matrix is in places porcellaneous, but in other places it is fine granular. In the center of the area over which quarrying operations have been carried on there out- crops fifteen feet of a hard, medium-grained, sandstone, mas- sive in structure, and of a good quality for jetty work, rip- rap, etc. In the extreme southern end of the quarry where operations are being carried on at present, there is a ledge of very hard, almost quartzitic sandstone, bluish-gray in color and made up of fiue rounded quartz grains set in a porcellaneous matrix. In the eastern side of the quarry, the section is as follows from bottom up: 1. Blue-colored massive arenaceous claystone, contains nodules of marcasite, not fit for quarrying 3 ft. 2. Bluish gray fine-grained sandstone, almost a quartzite, mas- sive; has a splintery fracture and is very hard 2 ft. 3. Fairly hard sandstone, grayish white In color and grading intoi thin bedded at top 4 ft. 4. Gray sand, overburden to be stripped 8 ft. 10 in. In the southwestern end of the quarry there is ten feet of extremely hard, fine-grained, bluish-gray sandstone with por- cellaneous cement and splintery fracture overlain by twelve feet of loose clayey sand. The sandstone everywhere contains iiiany rounded drab to gray clay balls and the coarser sand- 376 University of Texas Bulletin stone always contains abundant well preserved leaf impres- sions, reeds and palmetto leaves being predominant. Silicified wood fragments are also common. A quarry one-half mile north of Corrigan and one-quarter mile east of the Houston, East and West Texas Railroad shows at the western end a medium to fine-grained, medium hard, white to gray and yellowish brown, sandstone. This is for the most part massive, but exhibits some cross-bedding. Locally the sandstone contains hard rounded clay balls. In the eastern end of the quarry the hard sandstone grades into a thin-bedded softer rock. The rock in the western end of the quarry appears very well adapted for rip-rap and ballast, but in the ea.stern end it is too soft for these purposes. A graded spur connects this quarry with the Houston, East and West Texas Railroad. About one mile southwest of Corrigan there is a hill of por- ce]laneou.s sandstone. Tbei'c is a thickness of fully thirty-five feet of this sandstone exposed, but only half of it is said to be valuable. There are locally fragments of clay, some of which were rounded. The quartz grains of the sandstone are re- markable for their clearness, large size and angularity. Locally the rock is quartzitie. West of the Trinity no quarries have as yet been opened in the Corrigan quartzites in our area, but there has been some quarrying for' local use of the sandstone occurring in the upper portion of the Corrigan and the base of the Fleming. Kennedy says of the beds in Grimes county: These sand- stones are usually thinly bedded, rarely exceeding six inches in thickness, show a rough surface, and in quarrying break into irregular masses or slabs. Their texture is soft and coarse- grained, in places strongly calcareous, and often inclose small nodules or fragments of white clay. In color they vary from a soft gray to a white or creamy yellow. They are irregularly distributed in the beds, changing frequently from the consoli- dated sandstone to an unconsolidated mass of grayish yellow sand, and in this condition form a continuously alternating series of lenticular masses of sandstone and sand. The sec- The Geology of East Texas 377 tions exposed in the several quarries are made up of alternate strata of sand and sandstone. Exposures of these rocks occur at numerous places through- out the southern central portion of Grimes county and in the neighborhood of Navasota. The exposures seen near this place form a ridge extending from near the Navasota river in a northerly direction, skirting; the river bottom to Holland creek, a distance of about four miles. This same ridge then passes up the south side of Holland creek to the crossing of the Navasota and Anderson public road, where the sandstones are exposed over an area ofi several hundred acres. These rocks also appear on Grimes prairie and near White Hall post- ofSee and several other points along the northern side of the prairie. Sandstones in the neighborhood of Navasota belonging to this group have been quarried for building purposes for a great number of years. They were used in Navasota as building material almost exclusively. GRAVELS All of the gravel of this area which is of any commercial value comes in connection with deposits of Lafayette age. It is frequently mixed with sand or with clay and the workable deposits are limited in number. At Urbana a mile or two south of the Houston, East and West Texas Ry. Company's bridge over the Trinity river a gravel pit has been opened. The pit lies in a flat area bordering the river bottom proper ftnd lies at a slight elevation above it in an area not subject to overflow, the same constituting what might be termed the . "second bottom." The gravel has been found by boring, to cover an area of from seventy to one hundred acres and the depth of the gravel ranges from twenty-two feet in the west side to thirty-three feet in the east side. This is practically all workable gravel, as there is only a surface covering of from eighteen to twenty-four inches of fine gray sand. The pebbles in the gravel are rounded and up to two and a half inches in diameter, but they probably average about haK an inch. The 378 University of Texas Bulletin deposit runs about 40 per cent gravel, considering everything as gravel that remains on a one-eighth inch screen. The re- maining 60 per cent is a coarse-grained sand having angular grains. The gravel as loaded into the cars weighs 3,000 pounds per cubic yard. West of the Houston, East and West Texas Eailv/ay there are gravel deposits on a ridge which strikes west from near Willard, in Polk county. At the Watts place on the John Lindsey league a well was dug for water. At four feet they entered a red sandy clay containing the gravel and went out of the same at 221/2 feet. Mr. Watts also had a prospect hole dug to the depth of seven feet and the material from this hole was examined. The gravel was about one-half flint pebbles and the other half a stifE sandy clay, which when it gets dried out is very hard to pick into. The flint pebbles in the gravel vary in size from two inches to half an inch in diameter, averaging about one inch. This material would make an excellent ballast although it contains too much clay to admit of being economically washed for use in concrete construc- tion work. Similar gravel occurs northwest on the Hood farm in north- west corner of Cartwright league. Here there is a hill cover- ing some five or six acres, the surface of which is covered with a gravel consisting mostly of rounded flint and jasper pebbles averaging three-fourths to an inch in diameter. At Mr.' Hood's house a well was dug some thirty-six feet deep and it is re- ported gravel was encountered all the way down, but that it became more clayey toward the bottom. There are probably other deposits on the interstream areas where the Lafayette overlies the Fleming. Between the Trinity and the Brazos gravel deposits are found in the Lafayette and will doubtless prove to be of im- portance locally but they will probably not be as extensive as those west of the Brazos. INDEX Page Ackerman formation 53, 54 Actaeoh punctulatus Lea 95, 96 Agaronia punctulifera Gabb 95 Aguilares 305 Alabama 11 Alabama bluff 91, 125, 267 Alabaster : 164 /.Idridge 192, 199 Alticamelus 231 Alto 88, 141 Analysis, of clays 343 344, 348, 361, 353, 354, 356, 357 of iron ores 322, 323, 331 of lignite ..279, 280, 283, 284, 286, 287, 288 Ancilla ancellops Hulp 97 Stamlnea Conrad 91, 92, 95, 97, 100, 106 Anderson 236 Anderson County 3, 65, 146 Anemia eocenica Berry 125 Anseles. Mex 183 y^n^elina and Neches River Rv..-.118 Angelina-Caldwell flexure 200 Angelina County 3, 6 Angelina deposits 7 Anhydrite 25. 261 Annona Ohalk 22, 27, 295. 303 Anomia ephlppoides Gabb 71 89, 91, 95, 97, 99, 100, 103, 107, 108, 131, 138 sp 41, 224 Annua texana Berry 170 Anthony's Perry 182, 189 Antlers ; 15 Antonio 15 Aphelops 232, 237 meridianus Leidy . 238 Apoctiophyllum tabellanum 52 new .species 125, 170 Appalachian belt 11 Apple Springs 119, 122, 165 Apporhais sp. 33 Area rhomboidella 7-2 sp : 107, 171 Airchitectonioa meekana Conrad... 95 Areal distribution ; . . 32, 38, 45, 59, 62, 146, 189 Arenosa 74, 249 Arkadelphia clay 23 Arkansas 31 Arunijo pseudo'joeppertl Berry. . . .125 Asnlenium eolignitica 52 A^imira eocenica Lesquereux 37 Athens 59, 341 Aturia ,sp. near ziczac 96 Austin 15 Austin Chalk 5, 13, 9-> Avicula sp 92 Ayish Bayou 76, 194 Saline 313 Baculites 33, 48 Baker, C. L. 2, 34 41, 44. 64, 67, 109, 142, 172 Balonophyllialrrorata van. mortonl Gabb and Horn 107 Baldwin granite 200 Barbatia cuouUoides 43 Basalt 262 Bashi formation 37, 39, 53 Page Basin 25 Battls ferry isi Bayou Kegnet 64, 68, 73 Bayou Toro 191 Becker 2'36 Bedias 154 Bee shoals 49 Bell's ferry .'194, 196 Bell's Landing 37 Belosepia ungula 71. 78, 92, 93. 96, 97, 98, 100, 126, 128 Bend formation 11, 12 Benf ord Tram 175 Berry. E. W 37, 39, 55. 61, 81, 94, 123, 124, 164, 174 Bethea, J., Grant 289 Bevilport 192, 251, 266 Bergen sand 21, 31, 295 Rig Prairie saline 313 Bi,s Salt saline 309, '312 Bird Mountain ■ 258 Birdwell siding '. | 75 Birkinbine. J 7 Black Bluff. . .• ZZ, 49 Blanco beds 220, 244 Bland lake 74 Blastomeryx •232 -a-emmifer. . . . . ; 9.ZI -wellsi '.'. 232 Blos=om sand 21, 295 Blount, B. G 284 Blue shoals ' | . 33 Bluff crossing 106 Bluff saline '. '. .309 BlufBngton, Mrs 142 Rcatright headright 291 Bogtry Creek 150, 222 Bostick, J. W 2 Branner, J. 11. 12 Brazos County 3. 373 Brazos section 33 Brick 340 Are 341 Briquettes 282 Briquetting 276, 282 Broaddus 112 Brookfield bluff 90 Brookland 192 Brooks 9 Brooks, Bros '. !290 Brooks S'aline 26 Brown coal '.'6, 275 Brown's Mountains 322 Brownstown marl 1 . 22 Buccinanoos ellipticum 43 Buckley,. S. B 6, 318 Buda limestone 16, 17, 18 Buhlers ferry 196 Building ,stone 367 Bulimella kellogii Gabb 92, 171 Bu"a Vellogii Gabb 95 Bullard 65, 87 Bumelia pseudotenax 54 Buchard 31.8, 320, 329 Burke 141, 179, 273 Burkville 219, 261 Burkeville formation 29 -222 Buhrstone 5 55 Burnett County ' 15 Burr's Ferry 189, 222 Butler dome 299, 308 Byssoarca curuHoides Conrad.... 89, 92, 95, 97, 98, 99, 100 380 University of Texas Bulletin Page Caddell beds ..29, 147, 148, 152, 165, 171, 187 section 177 Caddo 22, 147, 295 Oadulus subcoarcuatus Gabb : 92, 96, 107 Calcote 249 Calhoun's ferry.' 125, 157 Calvert 59, 282 bluff 49 Calycites ostreaf ormis 54 Calyptrea sp 171 Calyptrophorus trinodiferus 44 valvatus Conrad 84, 93, 98 Cambrian, middle 11 Camilla 229, 259 Canary 208. 229 Cancellaria gemmata Conrad.. 9, 106 minuto Harris 98, 106 penrosei 148 quercolis 43 var. greggi 63, '89, 96, 106 tortiplica 95, 106 Capulus americanus 182 Carboniferous 106 Carium tuomeyi Aldrich 43 Cardita planicosta 10 " sp. .166 Oaricella demessa var texanum Gabb. . 92 subangula 89, 92 Carlisle bulff 265 Carmona 35$ Carpollthus n. sp '. '. 123 Carrizo 108. 133,137 sands 29, 55, 57, 61 springs 61 Carter'.s bluff '.'.'.' ' ' ' Vl 97 Cass County . . 7, 46, 59^ 66 Cassia bintonensis 54 Cassidaria brevicostata 84 brevidPntata 43 planotecta Aldrich 92', 107 sp 171 Catahoula formation „ ^ 9, 29, 170, 177, 182,'l86 Cedar Mills 19 C«drela sp ' ' 123 Center. . 277 Centerville \[ 67 Cerithiopsis burkevillensis ball ! . 224 Cerithium penrosii Harris 34, 48 sp. .^ 108, 113 vmctum Whitfield 89, 90 webbi Harris 1O8, 131 whitfleldi 34 Ceronia sp 43 45 C«rro Gordo ' ' ' ig Chalk bluff 134', '-212 Chama sp '.' 106 Chambers' ferry 41 63 Cherokee County 3 6 65 Ohireno 3O4 Chita ■...'.'.'! 209 Chrysodomus enterogramina Gabb 96 97 99 Cibota mississippiensi's Conrad. . .' 95 Cima 253 Cincinnati bluff I59 Cinnamonium affine Lesquereux.37, 52 Citrophyllum sp . . . 81, 125 Cladosporites fasciculatus Berry 94, 164 Claiborne 143 fauna 8 formation 26, 29, 56, 145 lower 56, 61 Mississipplan 56 sands 56 upper 56, 61 Page Clampitt tract 218 Clarke bluff 266 Clavilithes dumosa var. trapaquara 89, 92, 98 humerosa var. texana 89, 98 penrosei Harris. .... .71, 92, 98, 107 Clays 9,45, 338 brick •. 339 china 342 Are 339, 341 pottery 339, 346 slip 339 Clegg's shoals 162 Cleveland 256, 271 Climax 81 Close of Cretaceous 24 of Eocene 183 of Lower Eocene 54 of Neocene 160 Coast clays .246, 264 prairie 269 Costal domes 261, 262 Cockfield beds .71, 189 Colita 208 CoUard's Ferry 98 Cold S'prings . 220, 258 beds 29 Colmesniel 253 Columia 223 Columbian area 11,-44, 71, 110 formation 204 Columbus, La 44, 71, 116 Comanche Peak limestone 15 Comanchean 14, 18 close of 19 elevation 19 erosion 19 sea 13 Combretum ovalis 52 Concretions, calcareous 35, 36, 41. 138. 146, 221 cannonball 109, 122, 131, 183 limonite ...109, 113, 116, 124, 146, 167, 178 Cone-in-cone 117 Conn Survey 195 Conrad, T. A 56 Contact, Corrigan-Fleming 192, 218, 225, 241 Cretaceous-Tertiary 34 Fayette-Jackson 135 Fleming-Lafayette 236 Jackson-Corrigan.163, 196, 209, 213 Lafayette-Port Hudson. .. .259, 260 Marine-Yegua 86, 101, 103. 106, 111, 122 Midway-Lafayette. . ..34, 38, 45, 48 Wilcox-Olaiborne. .62, 66, 73, 78, 89 Yegua-Fayette 106, 133, 134 Yegua-Jackson 112, 117, 122, 147, 153, 157, 178, 180 Yegua-Lafayette .-. . . 255 Conu,s sauridens Conrad. 89, 92, 95, 97, 99, 100, 106, 108, 131, 137, 138 Cooks Mountain 7, 91 beds 57, 65, 66 Cope, B. D 44 Corbula, alabamensls Lea 44 92 93 96, 101, 106, 108', " '132, 148, 'l71 aldrichi, var. Steithvillense Har- ris 96, 97, 98 oniscus 110 171 texana Gabb. . ..74, 97, 99, lOO' 176 Cornelia armlgera 71, 92, 96, 97, 108, 131, 13'7","l38 Correlations 39, 60 Corrigan deposits 7 formation 9, 29, 145, 182, 187 Corsicana 25, 295, 298 The Geology of East Texas 381 Page Cottonwood formation 287 Courtney 358 Cragtn, F. W 17 Crassatella antistriata Gabb 106 flexura 171 srabbi 36 rotexta Conrad var 138 texana Heilprin 89, 92, 171 trapaquara Harris- 106 Creeks: Alabama 166 Alligator 194 Ata-scosa 108 Bedias 142 Bear 118, 193, 202, 361 Beef 268 Boi-riBas. 249 Bridge 178 Bug- 179 Calaveras ; 53 Cameron 289 Campbell 96 Cane. . . » 94 Cp,ney. . 165, 167 Carolina 211 Clear 178, 236 Oriswell 134 Dellards 158 Dean 169, 370 Dolores. . 132 Durano 83, 117 Elkhart 90 Elm 102, 106 Gail 273 Harmon 189, 215, 232 Kellison 125 Kickapoo 189, 207, 268 Louis-ville 164 Little White Rock 164 Lo-svs 44, 64, 67, 73 L.UOUS 360 Ma'on 41 McGee 210 Mill 84, 212 Muddy 281 Nails 106, 139 Neg-ro 267 N'elson 160, 217 Patoquacho 73 Penitentiary 226 Piney 167 Pond 33, 48 Procella. . . ' 84 Rocky 175, 189, 196, 207 Salt Branch 34 San Lorenzo 183 S'ha-wnee 198 SDrine- 126, 266, 271 S'tovall 179 Tak kiln 149 Tia-re 138 Town 269 White Oak 168 ■WTiite Rock 168, 209, 2S9 White's 150 Willis Wills S3 WriKht=!' 160 Cretaceous 13 beds 14 domes 261 elevation 24 fc^^ils 236. 238 islands 55, 57, 58 lower 11, IS .=ea ■ 14, 28 submurgence 3 UDOer 20, 23 Crihb's bluff 33 Crider 37 Crockett 91, 122 Page Crocodilus gryphus Cope 39 Crowther 295 Ciucullea macrodonata Whitfield.. 33 saffordi 36 Cummins. W. F 2 Cupanites, n. sp 125 Cupressinoxylon dawsoni. . .94, 123 Cylichna Kellogi 148 Cymbyola texana Gabb 95 Cytheria bastropensis Harris 96, 98, 101, 106, 137, 138, 148 texacola Harris ..89, 92, 93, 98, 99, 100, 108, 132 tomadonis Harris 96, 97, 99, 171 Dall. W. H 219, 224 Damon Mound 261 Davidson 81 league 150 Deane league 175, 266 Deep River beds 231 Del Rio 22 clays 16, 17 Denison 16 beds 17 Denny .station 134, 348 Dentalium minutistriatum Gabb.. 88, 95, 96, 97, 98, 99, 100 var. dumblii Harris 89, 96, 98, 99, 106, 171 sp. .166 Denver formation 53, 77 Deposition 31, 38, 57. 186 Deu-sen, A 5, 9, 31, 37, 53, 110, 148 Devil's bend 198 Dexter 28 Diatomaceous material 182 Dimmit County 61 Diospyros brachyse^tata 54 Dip 45i 122, 132, 195, 200, 234 Distortrix septemdentata Gabb... 89 92 93 95,' '96,' '97, ' 99,' ' 166,' 'loi, 105, ' Ditrupa subcorculus Gabb Dolichites deusseni Berry Dome oil Domes 25, 27, 55, 184, 296, Donovan Drake. N. F Drake's ==aline 20 Drew's Landing 229, Dromomeryx 232, Droddv's Landing Dryophyllum moori n. sp 123, Duck O-reek beds Duff siding 50, 64, Dumhle, E. T 2. 5, 7, 8, 10, Duna<2ran Dunn's r^nch 107 96 37 297 307 176 12 25 269 233 323 62 170 17 74 lOS 112 96 Fagle Ford 21 Faele Pass 23 Farle 37 Fa'st Prairie 164 Fastham's plantation 268 Fa-t Texas Coal Co 279 Fchinoderms 77 ■J^d ward's limestone 15. 17, 22 Flevations 236, 261 Flkins mountain 322 Flmendorf 346 T^lmo 33 Fl Paso 13. 16 Fnal 304 Fnplimatoceras ulrichi Wbitf..33. 36 T^ndonachys maclurii. .93, 97, 100. 107 Eocene 29. 30 upper 57, 147 middle , 38, 56, 134, 147 lower 30 382 University of Texas Bulletin Page Epicontinental seas H Equus 242 Erato seminoides Gat>b 35 Eriphyla trapaquara Harris 92 Erosion 64, 143, 147, 187 Erwin 240 Euschistodon reticulata Gabb.... 94 Evansville 280, 361 Evergreen crossing 106, 231 Exogyra arietina clays 16 Falls County 32, 33 Fasciolara juvinis 44 moorii Gabb 96 Pant 171 • sand 171 Fannin, W 288 Fayette beds ..7, 29, 57, 58, 102, 134, 149, 187 overlap 142 Ficus denveriana Coclierell 37 n. sp 126 occidentalis Le^quereux 37 planico^tata maxima 52 sciiimperi 52 37 sp. vaugliani. Fenneman. Fitzi. .62, 64 ... 9 78 Flabellum conoideum 36 cuneiforme Gabb and Horn 107 var. pachyphyllum Gabb and Horn 107 sp 96 wailegii Conrad .171 page Grand Gulf 9, 186 formation 182, 186, 187 Grand Junction 63 Grand Saline 20 Grapeland 272 Gravels 377 Graif's mountain 60 Grayson marls. 17 Greensand 45, 58, 64, 81 Gregg county 46, 59, 66 Grenada formation 53, 54 Grewiopsis tennesseensls 53 Gregg's landing 37 Grimes County 3, 8, 372 Grimes Mountain 60 Grimes station 153 Ground sloth 264 Groveton 122, 146, 164, 289, 371 Grypliea mucronata 17 Gulf coast sediments 4, 24 eocene 25 Gulf costal plain , 3. 13 Gypsum 20, 25, 28, 109, 184 crystals 67 Hager, L 2 Hall's bluff 5, 90 Hatton's ferry 189 Haminea gradis 171 Hamilton 40, 53 Hammock 180 Hanks, W., grant 252 Hardin County 3, 6 Harper tract 343 Harris County 259 TTie Geology of East Texas 383 Page Inga n. sp 125 Irona 74, 248 Interior domes 263 International & great Northern Ry 282 lola 153, 154 Iron mountain 323 Iron industry 7 Iron ore,s 6, 58, 59, 66, 318 carbonates 64, 66, 73 conglomerate 49 ?. laminated 321 nodular 319 Jack's tayou 141 Jackson 9, 145 formation, . 29, 59, 110, 145, 184, 187 Jacksonville 65, 66 87 Jasper 192, 249 Jasper County 3 Jefferson 62 Jewett 279 Johnson 30 Johnson's bluff 229 Jones' bridge 130 Jurassic 13 Keechi dome 300, 308 Keechl island 26 Kelley, W. "W 2, 151, 239 Kellum springs 291, 362, 364 Kelley's .switch 258 Kellia pruna 44 Kennard mill 258 Kennedy, W. . .-2, 7, 8, 33, 35, 46, 65, 86, 91, 107, 125, 149, 269, 303, 319 Kerr, W., tract 218 Kiamitla clays 17 King dome 36 Kittrell 158 Knight's landing 223 Knowlton 47 Koppe's bridge 151 Kruttschnitt, J 2 Kuykendall survey 103 Kyles quarry 374 Lacinia alveata Conrad 108, 131, 137, Lafayette ..29, 64, 70, 77, 81, 113, 116, Lagarto 29, 220, 236, Lamb S'prings Land, Barney Lapara 29, 220, Lapparia pactilis var. mooreana Gabb 92, 98. Laramide elevation 24, 25, 26 Las Guerreras bluff Latirus moorei Gabb . .88, 92, 96, 97, 98, 100, 101, Laurella. . Laurlnoxylon n. sp Laurus wardiana Knowlton Lea, Isaac Leda aldrichiana corpulentoides houstonia Harris 91, milamensls Harris 34 opulenta Conrad 95, 98, 100, 101, 106, 74, sp Leggett Leguminosltes arachiodes Les- quereux Leiostoma ludivlciana Lena Leon County 3, 64. Lerch, Otto 138 120 244 2'91 194 243 1'07 28 139 107 205 125 37 66 44 43 106 48 138 166 227 53 36 354 277 7 Page Levif usus indentus 43 pagoda 43 supra planus 43 trabeatoides 99, 100, 101 trabeatus -....43, 44, 108, 132 Liberty County 267 Lignite 7, 28, 43, 45, 58, 109, 275 Lignitic beds 37, 38, 39, 73 fauna 62 land 27 stage 29, 45 Limestone County 3, 6, 45, 277 Limonite 29, 64, 66 Lisbon beds 56 Little Rock 32 Llano 11, 12 Llano-Burnet 11. 14 Llanoria. 11, 1'2, 13 Loess 264 Lopansport 40 Longbridge 6 Longviewo 62 Lorimer 156 Lovelady 123, 273, 285 Low, Jesse, survey 27 Lowe, B. C., survey 195 Loup Fork 238, 243 Lucas headright 179 Lufkin 83, 84, 117, 119 Lufkin deposits 7 Lunulites 96 Lygodium kaulfussi Heer 125 mlssissippiensis Berry 170 Mactra sp. a 148 bistriata 44 Madracis sp 107 Madison County 3, 129, 287 Mainstreet limestone 17 Malakoff 341 Malone Mountain 13 Malvern 32, 54 Mammoth 264. 268 Mancha league 289 Manning 370 beds 29, 148, 156, 187 Manspeed 36 Manton Ill, 256 Many dome 36 Mararinella semen Lea 95, 110 Marion beds 38, 58 county 46, 59, 62, 66 front 58 substage 29, 57, 64 Marlbrook marl 23 -Marshall 6, 47 Martesia texana Harris 89 Mascall beds 233 Mastodon 233 Matthew, Dr, W. D 219, 231, 236 Matthews' landing 34 Matson, 187. 224 Maverick County 32, 61 Mazzalina plena 43 McClanahan's shoals 69, 249 McGee, J. W 246, 259 McGilreny bluff 179 McKem's prairie 309, 314 McLain 322 Melrose 6 Mendez, Mex 183 Meniphylloides ettinghauseni 53 Merychippus 225, 231 seversus. . . ■ 232, 237 Mesalia claibornensi,s Conrad 89, 92, 96, 97, 99, 100, 107 Mesozoic 11, 13 Mespilodaphne n. sp 123, 125 Metopium wilcoxianum 53 Mexia 34, 35, 29& 384 University of Texas Bulletin Page Mexico 11, 13, 22, 24 186 Midway fauna 8, 26, 30 stage. . ^^'„52 Milam 249 bluff; -oV ii county 'ooi Miller, R., survey ^^1 Mimositeg georgianus Berry 1^6 Mineral localities ^ Minter springs Ig^ Miocene • • ■ Ig^ Mis=is,sippi embayment, . . .13, 28, 54 MToffltt Springs 217 mooriana Gabb ^5 Modiola alabamensis 43 stubbsi 3 b Moffiitt Springs 217 Monoptygma crassiplica Conrad. . 95 Monterey, Mex 32 Monterey, Tex 112 Montgomery County 3 Moran's landing 41 Mormisia americana Berry 125 Morris County 59 iron 7 Moscow 204. 227 MOpSeley'"! Ferry _99 Mo^sy Hill 193 Mott, Jas 178 Mounds 272, 311 Mount Enteprise 67 Mount Salman 59, 248 M.ud volcanoes 294, 311 Munsou's .shoals 129 Murchison headriprht 90 Murex compsorhytis Gabb 94 Murfreesboro 15 Myrcia catahoulensis Berry 170 Myristica catahoulen,sis Berry.... 123 Nacatosh sand 23, 295 Nacogdoches 63, 78, 294 beds 57, 65, 67, 89, 265 N'acogdoches County 3, 6, 49, 59, 81, -264, 277, 352 iron ores 7, 322 Naheola 34 Nanafalia 37, 39, 40, 43 Napier 258 Nassa exilis 43, 44 Natica alabamensis 43 aperta 43 arata Gabb. . . .92, 93, 96, 97, 101, 107 eminula 43, 44 limula Conrad 92, 93, 96 Limula var 89, 107 newtonensis Aldrich 89, 98 recurva var. dumblii Heilprin. . 108, 131, 132, 137 pemilunata var. janthinops sp 36, 92, 107, 166 Natural gas 292 Navarro beds 23, 26, 29 county 3, 45 N'avasota beds 220 Nectandra lancifolia 53 n. sp 123, 125 n. var 123 sp 53 Nelleva junction 1S9 Neocene 29. 218, 219 Nentunea enterogramma Gabb.... 94 Neritira sparsalineata Dall 2'5 >"e verita arata Gabb 95 Nevil's prairie 123 New Birmingham 60 New Salem 323 Newton County 3 Niblett's shoals 99 Page Nimrod 256 Normanville 258 N'ucula magnifica Conrad „„ 95, 97, 101, 106 Nueces section 105 Nyssa n. sp 123 .231. Oakhurst Oakville Oakville formation 29, 189, Obsidian 204. Occulina sp 93 Odontaspis Oil Oil City ., : Olevilla bombylis var. burlesonis Harris ■ • • ■ • • ■ Oligocene 9, 24, 184, Onalaska 207, 209, beds 29, 189. Oolitic greensands Opaline matter Opaline cemented sandstone 123 157 209 Opalized 'wood'.'.'.'.'. .109, 147, 204] Orange sand 220, Orbitoides papyracea Bou Ordovician Orell's crossing Oreodaphne n. sp obtusifolia Oreodont Orogenic action Orasenic forces Orogenic movements. .35, 59, 143, yVustin chalk Upper Eocene Upper Pliocene Ostrea alabamensis Lea 92, 95, 108, 131, var. contracta Conrad. . . . ; 136, 137. 138, 139. crenulimarginata Gabb 33 georgiana johnsoni var pulaskansis Harris. . . .33, 36, 69 ;=ellaefornis Conrad 56, sp. var. divaricata Lea .". . 88, 90, 92, 95, 97, 98, 99, 108, Virginia Gmelin Ouachita sediments Owen,sville Oyster bluff > 33, 258 220 238 206 , 97 175 292 304 L 98 185 229 215 70 147 215 213 246 186 .15 104 125 53 232 4 13 261 5 5 5 132 171 , 36 136 72 72 106 76 132 224 12 281 48 Pachycheilus anaprramatis Dall...22'4 saltilensis Aldrich 224 sauvis Dall 225 Page 15 Palaganche 44, 249 Paleozoic 11, 12, 31, 32 Palestine 59, 67, 304 dome 20, 25, 143, 299, 308 Palmetto 221 Palmoxylon texense 193 Palm's fossil igg_ 221 Paludestrina plana Aldrich 225 Paluxy sand 14 Panola Coimty 3, 27, 49 57 iron .' 7 Parker survey 209 Patrick's ferry 229 Patroon bayou 41 Pawnee Creek beds .231 Peces ferry 199 Pecten claibornensis .' 39 cornuus gS deshaysil Lea gg^ gg ■sp .' 76 Pelican station 271 The Geology of East Teioas 385 Page Pennington .'.142, 164 prairie Pendleton 40 bluff 39 Pennsylvanian 1] Penrose, R. A. F. Jr 5, 6, 37, 60, 87, 102, 108, 134, 324 Perchoerus 231 PerlRue bluff 265 Perkins grant 252 Permian 12 Persea longipetiolatuni 53 n. sp 88, 92, 125 Pery ' 121 Petroleum 6, 292 Petunculua idoneus 72, 106, 171 .sp 171 Phelps 231, 259 Philleo furnace 324 Phillips, Drurv McN 9 Phillips, W. B 9, 285, 318 Pholadomya claibornensis Aldrich P sp. .171 Pholas alatoideus : 44 Phos 106 texana Gabb. var 89, 92, 93, 95, 96, 97, 100. 101, 107 Piedmont springs 291, 356, 362 Pilot Knob.' 24 Pine Bluff 128, 135, 267 Pine island 2^9 Pinna sn 106, 171, 176, 179 Planorbi=i 231 Plant remains 170 Platanu"! latifolia Knowlton 55 occidentalis. . . ., 37 Plate * Ill, 256 Plei."?tocene 264 Plejona praecursor 34 Plevo river 11, 13 Pleurotoma 104, 106 anacona 33, 36 bela Conrad 96 childreni Harris 96, 97, 98, 101 crassiplicata 106 enffonata Conrad.. 91, 92, 95, 99, 100 faunae Harris : . . 98 gabbi Oonrad 88, 91, 92, 95, 96, 97, 98, 99, 100, 106 huppertzi 44 infans 92 moorei Gabb 91, 95 var 100 natchi 43 nodocarinata Gabb.... 89, 91, 92, 95, 96, 97, 99, 100, 106, 108. 132 ostrarupis Harris 33, 48 Plenta Harris.. 95, 97, 99, 100, 106 var. bitota 106 quassalis 148 quasitus 101 reticulata 106 retifera Gabb 96 sulcata 43 ,?p 91, 92, 94, 95 terebriformi"! 110 texana var pleboldes Harris 92 texicona Harris 106 Plicatula fllamento'a 72, 89, 91, 95, 98, 106 Polk County 3, 264 Pollock 89 Pomeranes, Sierra de 184 Porcellaneous cement 109, r46, 147, ISS .oanflstone 192 Port Caddo landing 47, 53, 62 Port Hudson formation 230, 264 Portamides mat=!oni Dall 224 var. gracillior Dall 224 Page Potomac 173, 180, 289 Pottsboro 17 Pouroma texana Berry 37 Powell 295 Prado leaigue 164 Pre-Cambrlan 12 Pre-Cretaceous 11 Presidio del Norte 14 Preston beds 17 Prices crossing 104 Procamelus 237 Producer gas 9 Prosthennops 231 Protohippus 225 medius Cope 238 perditus Leldy 238 placidus Leldy 238 Pretolabis 237 Pseudoliva Pteropsis conradi Dana 96, 100 Pvrite 29, 73, 76, 212 Pvrula penita Oonrad var 96, 98 'texana Aldrich 97, 100, 107 Quaking bogs 273 Quartzite 140, 142, 154, 175. 201 Queen City 61, 65 beds 29, 38, 47, 54, 58, 61, 71 Raprsdale Mountain 60 Ramireno ranch 137 Ramones 32 Ranem .survey 229 Rapid=i 200 Ra=:pberry headright 207 Ratcliff 258 Renfroe place 140 Rhamnites berchemiaformis 54 Rhinoceras 242 Rice sands 146, 188, 206 Ridden, J. C 5 Ries, H 9, 338, 344 Rimella texana var, plena Harris. 89, 98 Ringicula trapaquara Harris 106 Rio Grande embayment 24 Ripley sea 31 Rivers: • Angelina. . 30, 82, 116, 117, 178, 265 Atascosa 59 Attoyac 116, 249 Brazos 21, 29, 30, 32, 45, 67 Colorado. . .14, 16, 18, 21, 23, 32, 45 Conchos 183 Devils 17 Frio 32 Litle Brazos 34, 101, 129 Navasota 30 N'eches 117 Nueces ■ Old 135 Pisquiera 32 Red 16, 21, 27 Rio Grande 14, 22, 23, 32, 107 Sabine 29, 30, 38 Palinas 32 S'an Jacinto 266, 259 Trinity 6, 29, 30. 266 Tegua 102, 107 Riverside 163, 210 Roan's Prairie 217 Roark'.s gravel pit 258 Robbin's ferry 94, 110, 125 Robertson County 3, 8 Robin's ferry. 181 Rock Bluft 40 Rockdale 282 Rockland 195, 253 Rocky Mountain chain 24, 25 province 53 386 University of Texas Bulletin Page Roemer, P 99 Roock league '217 Roma 136, 139 Rose quartz 210 Rusk 60, 87 county 3, 6, 49, 65 iron 7, 323 Sabalites grayanus 53, 54 vlcksburgensis Berry 170 S'alinas movement 24 Saline embayment 299 formation 38 parish 38 peninsula 26, 55, 57, 68, 261, 299, 301 phase 40 stage 29 Sabine Pass 6 Sabine River beds 38, 64 S'abinetown 26, 27, 63 Sabinetown bluff 38, 39, 43, 248 ferry ■_■ 43 S'alinas barrier 24 Saline 272, 309 Salmon 272 gait 25, 28, 261, 296, 307 deposits 20 domes licks 309 rocks 262 San Augustine 63, 76, 249 San Augustine County 3, 6, 49, 59, 74, 178 S'an Fernando ° 183 San Ignacio 132 Sand basal dunes hills Sandstone 367 Sandstone dikes 179 Sapindus bintonensis 54 formosa 125 georgiana Berry 125 lineariforlius 54 Saratoga 294 S'aspamco 346 Scala sp 126 S'chuchert, C 11 Scobinella crassiplicata Gabb 94 leviplicata Gabb 94 Scott, W. B 2 Scutella 70 caput-leonensis 89 Sections: Aaron's hill 79 Alto 88 Angelina river 194 Bowie Hill 320 Brazos and Grimes county 149 Brazos river.. 48, 97, 129, 218, 238 Burkeville. 223 Cold Spring's 230 Colorado river Cooks Mountain 91 Gibson gin 49 Groveton 165 Groveton-Lufkin & Northwest- ern Ry 119, 165 Hidalgo Blutt 239 Houston East and Wast Texas Ry..63, 78, 117, 170. 200, 227. 256 International and Great North- ern Ry.l22, 153, 163, 213, 217, 231 Irma 74 Kickapoo creek 207 Man'ing 176 Mt. S'elman 87 Nacogdoches 79 Page Neches river 197 Orton Hill 79 Pendleton bluff 42 Rio Grande 130, 136 Rusk 88 Sabine river 40, 67, 87, 110, 181, 189, 222 S'abinetown bluff 43 San Augustine 75, 76 Santa Fe Ry . .50, 64, 74, 111, 180, 192, 225, 249 St. Louis & Southwestern. .86, 112 Tehuacana ; 34 Te.xas and New Orleans Ry. . . . Ill, 195, 226, 253 Texas Southeastern Ry 119 Trinity Brazos Valley Ry 152 Trinity river.. 89, 125, 157, 210, 229 Westmoreland bluft 127 Whellock 94 Wills Point 35 Selenite 81. 84, 103, 109, 118, 122, 179, 184, 202 clastic 109 S'emele lienosa 137 Sevenoaks 227 Shale Oil 297 Shawnee prairie 176, 179 Shelby County 3, 27, 49, 57, 277 iron 7, 322 Shepherd 256, 258 S'hiloh 35 Shipp's ford 143 Shreveport 191 Shumard. B. F 5, 242, 318 Slderite 28 Sierra Blanca .• 13 Sigaretus declivis Conrad 44, 93, 96, 97, 98, 99 incinstans /.Idrich 96. 101 Silicified wood 109, 112, 120, 122, 141, 154, 166, 194, 250 Siliqua simondsi 148 Silurian, upper 11 Simonds 9 Singleton 153, 156, 217 Smiley's bluff 33, 48 Smith County 26, 59, 65 Smith, Eugene 30 Smither's farm 215 S'mlthfleld ■ 229 Smith's ferry 199 Snell's landing 190 Soil. .181 Solarium acutum, var. meekanum 89, 96, 97, 99, 100, 107 alvatum 98, 107, 171 bellastriatum 107 bellense 43 huppertzi 107, 171 scorblculatum 96, 97, 98, 107 vespertinum 96 Sonada, Mex 183 Sophora wilcoxiana Berry 125 Sour Lake 6, 145. 294 South Texas Coal Company 279 Southern Pacific Company 12 S'outhwestern Fuel Company 282 Spanish Bluft 127 Rpharella antiproducta 49 Sphaerodial weathering 206 K'pindletop 275, 294 Spirorbls leptostoma Swain.... 92, 95 Splendora. 256 Spring 259 Spring Line '70 Star and Crescent Mines 329 Starr County 136 .''tate farm 235 State mines 329 Tlie Geology of East Texas 387 Page S'teen's Saline 25, 26 Stephenson, L. "W 37 Stephenson league 148 Sterculia n. sp 125 Stivers' Saline 309, 314 Stone. Robert, grant 194 Sucks 273, 311 Sulphur 28, 261, 296 Sulphur bluff 130 Sulphur Springs 291 S^iman, J. R 2, 93, 109, 141, 170 Summit 221 Sun Mounds 260, 261 S'ymola trapaquara Harris. . .107, 144 S'ynecodus 78, 175 Taff, J. A Tallahatta 55, Tamaulipas range. 24, 56, Tampico .' Tarkington prairie Ta>T=ie Bell furnace Taylor marl 23, Tehuacana Teleoceras 225, Tellina mooreana Gabb 101, 108, 132, 137, 138, sp Tenuiscola Tepetate. Mex Terebellum sp Terebra houstonia Harris. .88, 95, texasyra var, Harris 92. Terminalia hildegardiana Lesau- ereux 37 Terraces 208, 251, 266, Terrell Terry Tertiary formation fossils sands sea section Tetrabeledon Texarkana Texas Grading Company quarry. . Thompson Bros. Lumber Co Thompson lieadright Thorp, Jane, survey Thornton Thrall Timber Belt beds 7, 31, 38, Timpson Tishomingo Titanotherium Topography 46, 49 59, 109, 141, 177, 181, 193, -204, Tordo bay Town bluff 226, 251. Trans-Pecos 16, 24 Transitional beds 33, 65, 188, Travis Peak sand Trewick's bluff 84, Triassic -. ■ Trlforis Trigonarca corbuloides Oonrad. . . . pulihl-a' Gabb '.'.'.'AH 'sV, ' 9l', 95', Trilophodon 230, 231, 232, euryphodon Tritonidea pachecci ■ . • ■ Trinity Ko. County • • ■ formation 14 Trinity-Neches divide Troohita sp • • • ■ • Trochosmilla mortoni Gabb Trosper farm Truitt place 17 56 183 25 271 329 298 34 232 171 171 100 184 89 101 106 , 53 268 7 ■261 28 29 8 10 29 29 230 26 375 162 90 27 34 .295 102 278 15 242 '260 24 252 , 25 221 14 265 13 107 101 106 233 231 43 162 3 , 20 ,147 98 , 93 302 ,193 Page Tuba antiqua, var. texana. .96, 99, 107 Turginolia pharetra Lea 92, 93, 96, 97, 98, 100, 107 Turpentine 289 Turricula polita Gabb.. 92, 96, 99, 107 171 92 94 94 94 94 100 107 171 43 93 43 166 37 62 3 164 sp texana Turris kelloggi Gabb nodicarinata retifera Turritella dumbli Harris.. 96, 97, dutexta 89, houstonia 107, 108, 132, mortoni 36, nasuta var 71, praecincta. . . /. »r 53, 98, 104, 105, 148, 155, Tuscahama Tyler County prairie Udrlen, J. A'. 2, 12 Udell, C. B 258 Umbrella planulata 182 Unconformities 81, 82, 250 Unio sp 69, 128, 236 Union Hill 362 Upshur County 59, 66 iron. . 7 Urbana 258 Urbana gravel pit 377 Uvalde 12 Vair 122 Van Zandt County 33, 45 iron 7 Vaughan, T. W 62, 107, 145 Veatch. A. 5, 9, 38, 40, 47, 68, 110, 143, 145, 178, 186, 187, 222 Venericardia alticostata 33, 36 var. perantiqua 133 planicosto Lamarck 36, 41, 44, 48, 66, 69, 88, 92, 93, 96, 97, 98, 99, 100, 101, 106, 108, 132, 137, 138, 148, 155, 171 rotunda Lea 88, 98, 171 sp 74, 176 Vertebrates 231, 236, 242 Vicksburg formation 9, 145, 185 Vivian 27 Volcanic ash 24, 146, 154, 182, 188, 202, 361, 362 eruptions 4, 146, 187 necks 5 tuft 163, 168, 183 Volcanoes. ' 147, 206 Volga 267 Volutilitbes 104, 137, 176 dalli Harris 96 limop.sis Conrad 36 petrosa Conrad. 44, 88, 89, 92, 95, 99, 100, 107, 108, 132. 137, 138, 171 var. indenta 89, 92, 96, 97, 98, 107, 108, 132 praecursor Dall. . . .89, 92, 96, 97, 99 rugatus 36 sp 69 Volvula conradiana Gabb 91, 95 • minutissima Gabb 106 "Waco 6, 24 "Wailes 186 Walker County 3 Walker, J. B 7 ^V^alnut clays 15 Warsaw 116, 255 Washington 242 Washita formation 16 388 University of Texas Bulletin Page limestone 16 Water supply 9 Waters Park 295 Webb County 131 Webberville 23, 32 Weiser's Bluff 159 Weldon 126 Welborn 145 beds 29, 142, 147, 148 Wells, Cleveland 257 Espersa 297 Flat Fork ' 302 Groveton Light and Ice Co 289 Lucas 294 Marshall 47 Mexico Oil and Gas Co 298 Mineola 47 Palmetto Petroleum Co 302 Producer 301 Sulphur Springs 48 Wells, Texas 89 West Point 134 Westcott 258 Westmoreland bluff 126, 266 Westville 168 Wheelock 94, 282 White Bluff marl 256 White City 178, 179, 255 White Marl Bluff 134 White Rock ghoals 212, 267 "Wicker Slarvey 169 Wilcox '. 37 fauna 8, 25, 39, 45 Page formation 29, 37 Wilkins mill 62 Willard 154 Williams quarry 148, 150 Willis 232, 268 Willow switch 62, 260 Wills Point 32, 35 Wilson County 53, 59 Winfield 143 Wood County iron 7 Woodbine 18 formation 20, 21, 25, 29, 294, 300 Woodville 246 Wood's Bluff 37, 39,- 44 Wooters Bluff 90 station 123, 284 Worril 9 Wortham 34, 298, 340 Yazoo City 145 Yegua age 106 beds .29, 8« deposits 7, 58 substagc 57, 65, 102, 296 Yoldia aldrichiana 101, 137 claibornensis 95, 101, 148 Young's furnace 321 Zapata 108, 136 county ,..131 Zavalla 289 Zana 252 Zenyloda 145, 178