Cornell University Library QE 168.S6U18 The deep boring at Spur 3 1924 004 622 084 Cornell University Library The original of this bool< 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/cu31924004622084 BULLETIN OF THE UNIVERSITY OF TEXAS NO. 363 SCIENTIFIC SERIES NO. 28 OCTOBER 5, 1914 BUREAU OP ECONOMIC GEOLOGY AND TECHNOLOGY WILLIAM B. PHILLIPS, Director THE DEEP BORING AT SPUR BY J. A. UDDEN GEOLOGIST FOR THE BUREAU SECOND PRINTING 1926 Published by the University six times a month, and entered as second-class matter at the postoffice at Austin, Texas 3)S CONTENTS Page Introductory Note 7 History 7 Acknowledgments 9 The driller's record 9 Explanation of terms used 18 Methods and rate of drilling 19 Study of rock samples 1 20 Taking of the samples 21 Mixing of returns in rotary drilling 21 Descriptions of samples . 22 Description of the formations explored in the Spur borin,g: ^ 52 The Red Beds 53 Upper part 53 Middle part .___. 53 Lower part 54 Salt of the Red Beds 55 Gypsum and Anhydrite 55 Calcareous material . 56 General character of the Red Bed sediments 56 The Dolomite Beds 57 The dolomite 57 Crystalline texture 57 Size of dolomite crystals 58 Chemical composition _ 59 Clastic texture 60 Oolitic dolomite 60 Dolomite of fragmental and other texture 62 Distribution of textures 63 Interbedded sands .__ 64 Interbedded shale 65 Anhydrite 67 Secondary anhydrite 68 4 Bulletin of the University of Texas Page Origin of the anhydrite — VO Other minerals 71 Quartz 71 Calcite 71 Pyrite 72 Gypsum and salt 72 Bitumen and ammonia : 72 The Cisco Formation 74 Limestone 74 Shale 75 Notes on fossils i 75 Fossils in the Cisco 76 List of fossils from the Cisco formation 76 Fossils of the shaly dolomitic beds 84 Fossils from the sandy dolomitic beds 84 From 2267 to 2956 feet 84 From 2244 to 2264 feet ' 85 From 1250 to 2042 feet 86 Economic results 87 Water 87 Discovery of potash 87 Analyses of rock samples 91 Prospecting for potash 93 Westward dip of strata 93 Outcrop of potash-bearing horizon 95 Potash in other well-waters in Texas 95 Oil and gas 96 Index 99 LIST OF ILLUSTRATIONS Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, Figure 10. Figure 11 Figure 12. Figure 13 Figure 14, Figure 15, Figure 16, Figure 17, Figure 18, Plate 1. Plate 1. Plate 2. Plate 3. Plate 4. Plate 5. Plate 6. Page Section of dolomite from 1250 to 2042 feet below surface . 27 Section of oolitic rock from same depth 28 Section of another rock from same depth- 29 Foraminifera from the Cisco 77 Unknown foraminifera from the Cisco.— 77 Foraminifera from the Cisco 78 Foraminifera from the Cisco 78 Foraminifera from the shaly dolomite and the Cisco 79 Foraminifera from the Cisco 79 Foraminifera from the Cisco - 80 Foraminifera from the Cisco 81 Sponge spicules 82 Fossils from the Cisco 82 Fossils from the Cisco 83 Fossils from the shady dolomite 84 Fossils in thin sections of dolomite 85 Fossils in thin sections of dolomite 86 Sketch map of a part of Texas 94 Following Page A. Thin section of oolitic dolomite 102 B. Thin section of dolomite 102 Vertical section of dolomite from 1600 feet below surface 102 Vertical section of dolomite containing an- hydrite 102 A. Photograph of a piece of core. B. Section of a concretion 102 Section of dolomite showing oolitic spher- ules and some organic structures 102 Section of dolomite showing oolitic spher- ules and some organic structures 102 List of Illiistrations Plate 7. Plate 8. Plate 9. Plate 10. Plate 11. Plate 12. Plate 13. Plate 14. Plate 15. Following Page Section of dolomite of organic and oolitic origin -■- 102 Vertical sections of oolitic dolomite 102 A- Horizontal section of siliceous dolomite. B. Horizontal section of oolitic dolo- mite 102 Horizontal sections of dolomite 102 Horizontal section of dolomite 102 B. C. Horizontal sections of dolomite 102 A. B. Horizontal sections of dolomite 102 Horizontal section of limestone 102 General section of Spur boring Insert THE DEEP BORING AT SPUR BY JOHAN AUGUST UDDEN INTRODUCTORY NOTE In the northwest part of the State, east of the Pecos, the formations lie nearly horizontal. This structure prevails over the entire Plains, extending from the north end of the Panhandle to a line joining San Angelo and Pecos on the south. This area measures 330 miles from north to south and 170 miles from east to west. The deeper lying rocks can hence be known here only from inferences based on their appearance in distant outcrops outside of this area and from such local observations as may be obtained from deep explor- ations. It is singularly fortunate for our knowledge of the stratigraphy of this part of the continent that a deep boring was made at a point not far from the central part of the area delined. The exploration enables us to know by actual observation what strata underlie. It will enable us to say with greater accuracy what other borings will pene- trate even at considerable distances from this exploration. It furnishes firsthand information on the stratigraphy of this part of the State. While this paper describes the section of a single boring, it really gives the only facts so far known concerning the deep stratigraphy of a region cover- ing one-fifth of the area of this State. HISTORY The deepest boring in Texas is now (1914) at Spur, in Dickens county, south of the east portion of the Panhandle. This boring has been made by large landholders in this and adjoining counties, in search of water for the town of Spur, and as a general exploration of the formations for the 8 Bulletin of the University of Texas vicinity. Spur is the present northwest terminus of the Stamford & Northwest^n Railway. The boring is located . about a half mile southeast from the railroad station, with the curb at 2335.4 A.T. Work on this well was begun in June, 1909. The drilling rig had been hauled overland from Rotan, in Fisher county, which was at that time the nearest railroad point to the Spur Ranch. All the work was done with a rotary machine, and Mr. H. P. Minihan, who was engaged as driller, con- tinued in charge throughout the entire operation. The hole was abandoned and wrecked in November, 1913, at the depth of 4489 feet. The cost of the boring was slightly more than ten dollars a foot, or nearly $50,000.00, including the cost of the rig, piping and all expenses. The salvage brought the net expense down to about $45,000.00. The first serious difficulty encountered in this work was the caving of sand at the depth of sixty feet. This was remedied by setting a ten-inch casing at 60 feet and 6 inches. Later it was found necessary to set an eight-inch casing at 476 feet, a six-inch casing at 1357 feet, and a four- inch casing at 3044 feet. From this last depth to the bottom the hole was not cased, and the drilling through the four- inch casing was done with a three and seven-eighths-inch bit. Mr. C. A. Jones, the manager for the company, under whose directions the work was done, writes concerning the undertaking as follows : "The remarkable feature of the boring was the continuity and the persistency of the rock. The log will show what a tremendous bed of rock was penetrated. At different times, due to imperfect method of securing cones to the drillhead, in the roller bit, cones were lost in the well, giving us serious fishing troubles. The final failure was due to this cause. A cone was lost in the well and in attempting to go after it, the fishing line was lost in the well, probably owing to caving. It was impossible to free it, and after several months of attempts, with every variety of fishing tool that could be suggested, the well was abandoned. It is a matter of great regret that we were compelled to The Deep Boring at Spur 9 abandon this well, but it was something of an achievement to have made the deepest exploration in the state." Through the kindness of Mr. W. E. Wrather, the writer's attention was first called to the work on this boring in the latter part of December, 1911, when it had reached a depth of 2600 feet. We jointly made a visit to Spur and secured a log of the ground explored. I also examined some pieces of core, which had been taken and preserved. Arrange- ments were at the same time made with the manager, Mr. C. A. Jones, to furnish to the Bureau of Economic Geology and Technology cuttings from all depths possible. It is due to the generous policy in this matter on the part of Mr. Jones that it is now possible to describe in considerable detail the strata penetrated and to verify and correctly interpret the long record, which was kept with more than usual care by the driller, Mr. H. P. Minihan. A cknowledgments The detailed examination of a large number of samples, which consumed much time, was in part made possible by the assistance of the U. S. Geological Survey, for which the writer wishes to express his obligations. The same survey has also kindly made all but one of the photographs . for the plates of this bulletin. The Driller's Record Feet below surface. Thick- Prom. To. ness. 1. Brown soil 2 2 2. White porous material 2 6 4 3. Yellow sand 6 16 10 4. Sand and gravel, water 16 23 7 5. Hard concrete of light color 23 27 4 6. Tough red clay 27 53 26 7. Hard concrete 53 65 12 8. Isinglass (selenite) and red clay 65 75 10 9. Hard, flinty rock 75 85 10 10. Red clay and red sand rock 85 98 13 11. White chalky rock *. 98 101 3 10 Bulletin of the University of Texas 12. Isinglass (selenite). 13. Red clay and red sand rock.. 14. Isinglass (selenite). 15. Red sand rock, thick streak of red clay — 119 16. Red clay, thin streak of blue clay. 17. Red clay and sand rock 18. Red clay and isinglass (selenite). 19. Red sand and clay 20. Isinglass (selenite) 21. Red gumho- 22. Isinglass (selenite) and gypsum.. 23. Red gumbo 24. Isinglass (selenite). 25. Soft red sand rock 26. Soft red clay.. 27. White flinty rock and isinglass (selenite) 28. Sand, salt water 29. White flinty rock 30. Red sand rock 31. Hard gray sand, and red sand.. 32. Soft white clay 33. White hard flinty rock.. 34. White tough rock 35. Hard white flinty rock.. 36. Salt rock 37. Brown sand rock.. 38. Hard white flinty rock.. 39. Brown sand rock 40. Tough white rock 41. Hard white flinty rock.. 42. Hard brown sand rock.. 43. Salt rock. No sample.. 44. Light soft rock 45. Hard sand rock 645 46. Notes wanting 47. Hard sand rock 48. Soft sand rock 49. Soft white rock, hard in streaks.. 50. Salt rock 51. Hard concrete sand rock.. 52. White flinty rock 53. Concrete sand rock 54. Sand rock and red gumbo.. Feet below surface. Thick- From. To. ness. 101 108 7 108 115 7 115 119 4 119 135 16 135 137 2 137 149 12 149 153 4 153 192 39 192 199 7 199 221 22 221 223 2 223 239 16 239 254 15 254 272 18 272 285 18 285. 298 13 298 330 32 330 403 73 403 468 65 468 532 64 532 538 6 538 540 2 540 568 28 568 570 2 570 580 10 580 586 6 586 596 10 596 603 7 603 624 21 624 628 4 628 633 5 633 638 5 638 645 7 645 674 29 674 688 14 688 715 27 715 725 10 725 732 7 732 741 9 741 773 32 773 778 5 778 804 26 804 812 8. The Deep Boring at Spur 11 Feet below surface. Thick- Prom. To. ness. 55. White flinty rock 812 816 4 56. Red sand rock 816 853 37 57. White flinty rock 853 858 5 58. Red sand rock 858 931 73. 59. Hard blue rock 931 932 1 60. Notes wanting 932 958 26 61. Red sand rock 958 1113 155 62. Gray lime 1113 1117 4 63. Red sand rock 1117 1123 6 64. Gray lime rock.. 1123 1125 2 65. Red sand rock 1125 1174 49 66. Soft white rock 1174 1222 48 67. Gray lime rock 1222 1235 13 68. Soft white rock 1235 1250 15 69. Hard gray rock 1250 1252 2 70. Hard limestone 1252 1270 18 71. Very hard lime rock 1270 1272 2 72. Hard limestone 1272 1302 30 73. Very hard limestone 1302 1309 7 74. Hard limestone 1309 1313 4 75. Hard blue rock 1313 1327 14 76. Hard limestone 1327 1335 8 77. Blue rock 1335 1337 2 78. Hard limestone 1337 1341 4 79. Somewhat soft limestone. 1341 1347 6 80. Very hard limestone 1347 1349 2 81. Lime and blue rock 1349 1364 15 82. Hard lime rock 1364 1370 6 83. Blue lime rock 1370 1376 6 84. Hard lime rock 1376 1390 14 85. Limestone 1390 1391 1 86. Hard limestone ^ 1391 11397 6 87. Hard limestone with soft blue streaks 1397 1403 6 88. Hard limestone 1403 1419 16 89., Lime rock 1419 1425 6 90. Hard lime rock with soft streaks 1425 1433 8 91. Hard lime rock 1433 1454 21 92. Hard lime rock with soft streaks 1454 1461 7 93. Hard limestone 1461 1478 17 94. Very hard rock 1478 1483 5 95. Hard rock . 1483 1502 19 96. Sand rock, fossils 1502 1503 1 97. Blue rock 1503 1506 3 12 Bulletin of the University of Texas 98. 99. 100. ■101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117. 118. 119. 120. 121. 122. 128. 124. 125. 126. 127. 128. 129. 130. 131. 132. 133. 134. 135. Feet below surface. Thick- From. To. ness. Sand, lime, and blue rock 1506 1510 4 Hard blue rock 1510 1514 4 Blue and gray rock 1514 1520 6 Hard gray rock 1520 1523 3 Very hard gray rock 1523 1525 2 Hard gray rock 1525 1538 13 Blue and gray sand rock 1538 1546 8 Blue sandy and slaty rock 1546 1551 5 Blue sandy rock 1551 1554 3 Hard gray rock 1554 1555 1 Gray and blue hard rock 15.55 1558 3 Hard gray rock 1558 1560 2 Hard gray and blue rock 1560 1563 3 Very hard gray rock 1563 1575 12 Very hard gray flinty rock 1575 1579 4 Gray, blue, and yellow rock 1579 1581 2 Hard blue rock : 1581 1595 14 Gray and blue rock 1595 1599 4 Blue rock 1599 1600 1 Hard gray rock 1600 1619 19 Gray and blue rock 1619 1631 12 Hard blue rock 1631 1639 8 Hard blue and gray rock 1639 1645 6 Hard gray rock 1645 1651 6 Very hard gray rock... 1651 1655 4 Hard gray rock. 1655 1668 13 Blue and gray rock 1668 1676 8 Hard blue rock , 1676 1688 12 Gray and blue rock 1688 1703 15 Very hard flinty blue rock 1703 1704 1 Very hard sand rock above and then very hard sand and flint rock. Very rough. Rock seemed to have a split in it 1704 1705 1 Gray rock. (Mr. W. E. Wrather, who examined this piece of core, describes it as a rough-grained, hard cemented sand rock) 1705 1707 2 Hard blue and gray rock 1707 1730 23 Very hard blue flinty rock 1730 1738 8 Hard blue rock 1738 1741 3 Hard blue and gray rock 1741 1780 39 Hard flinty rock 1780 1783 3 Hard gray and blue rock 1783 1794 11 The Deep Boring at Spur 13 Feet below surface. Thick- From. To. ness. 136. Hard blue rock _.. 1794 1799 5 137. Hard blue and gray rock 1799 1803 4 138. Hard gray rock, quit in very hard .sand rock 1803 1805 2 139. Very hard sand rock. Had split in it. ■ Very rough 1805 1806 1 140. Upper six inches very hard sandy, flinty rock, rough; had crack in it. Lower two and a half feet is very hard blue flinty sand rock 1806 1809 3 141. Very hard blue sand rock 1809 1810 1 142. Hard blue rock 1810 1816 6 143. Hard gray and blue' rock. Quit in flint at 1823 1816 1823 7 144. Very hard sand and flint rock 1823 1824 1 145. Hard sand and flint 1824 1825 1 146. Blue rock 1825 1826 1 147. Hard flint rock 1826 1827 1 148. Hard sand and flint rock in the upper six inches, then flint sand and blue rock 1827 1830 3 149. Blue rock with flint at bottom 1830 1838 8 150. Flint and blue rock 1838 1845 7 151. Gray and blue rock 1845 1851 6 152. Hard blue rock with streak of flint 1851 1855 4 153. Gray and blue rock 1855 1860 5 154. Hard gray sand and flint 1860 1862 2 155. Very hard sand and flint and very rough sand and flint 1862 1863 1 156. Flint and sand a few inches, then blue rock 1863 1864 1 157. Blue rock 1864 1874 10 158. Hard blue rock and flint rock ;. 1874 1877 3 159. Blue rock with sand and very hard flint rock in bottom 1877 1884 7 160. Hard blue rock 1884 1898 14 161. Gray and blue rock. Some sand in it 1898 1910 12 162. Blue rock, not very hard 1910 1936 26 163. Hard gray rock 1936 1938 2 164. Very hard blue rock 1938 1952 14 165. Flint and blue rock 1952 1955 3 166. Blue rock 1955 1964 9 167. Hard blue rock 1964 , 1969 5 168. Blue and gray rock 1969 1975 6 14 Bulletin of the University of Texas Feet below surface. Thick- From. To. ness. 169. Hard gray and blue rock; 3 feet gray above, 2 feet blue below 1975 1980 170. Hard gray and blue rock, gray rock and flint, and sand rock.. 1980 1988 8 171. Very hard sand and blue rock 1988 1992 4 172. Hard blue and gray rock 1992 2000 8 173. Grayish blue and gray rock, with flint below 2000 2007 7 174. Very hard flint and sand rock 2007 2008 1 175. Flint and blue rock, very hard 2008 2011 3 176. Very hard blue rock 2011 2014 3 177. Gray and blue rock 2014 2027 13 178. Hard gray rock with streaks of blue.: 2027 2032 5 179. Hard blue rock with flint in lower part...... 2032 2036 4 180. Hard blue rock with streaks of flint 2036 2041 5 181. Hard blue rock 2041 2042 1 182. Blue shale 2042 2047 5 183. Soft red sand rock, water 2047 2049 2 184. Blue and gray rock 2049 2050 1 185. Hard gray and blue rock 2050 2059 9 186. Very hard blue rock 2059 2063 4 187. Flint 2063 2064 1 188. Blue and gray rock 2064 2068 4 189. Soft red sand rock, hard in streaks 2068 2107 39 190. Red sand rock and hard gray lime rock 2107 2115 8 191. Very hard gray limestone, almost flint 2115 2126 11 192. Blue rock 2126 2128 2 193. Gray, blue and red sand rock 2128 2131 3 194. Hard red sand rock 2131 2162 31 195. Red sand rock, not very hard 2162 2176 14 196. Hard red sand rock 2176 2204 28 197. Very hard sand rock 2204 2209 5 198. Very hard red sand rock 2209 2211 2 199. Hard blue lime and flint rock. 2211 2214 3 200. Very hard flint rock (three days' drill- ing) 2214 2216 2 201. Very hard sand and flint rock (three days) 2216 2219 3 202. Blue limestone 2219 2223 4 203. Very hard flint and limestone 2223 2224 1 204. Very hard limestone 2224 2226 2 205. Very hard blue limestone and flint 2226 2236 10 206. Very hard limestone and flint 2236 2239 3 The Deep Boring at Spur 15 Feet below surface. Thick- From. To. ness. 207. Very hard blue limestone and flint 2239 2240 1 208. Very hard sand and flint rock 2240 2242 2 209. Very hard sand rock 2242 2243 1 210. Very hard sand and flint rock 2243 . 2244 1 211. Sand in flint rock (core) ...2244 2250 6 212. Very hard sandstone (core), much pyrite near this depth reported by Minihan.... 2250 2270 20 213. Hard blue lime rock (core) 2270 2274 4 214. Blue limestone 2274 2276 2 215. Red sandstone 2276 2278 2 216. Hard lime rock...! 2278 2281 3 217. Very hard lime rock 2281 2287 6 218. Very hard limestone and flint 2287 2291 4 219. Very hard blue lime rock 2291 2296 5 220. Very hard lime rock 2296 2298 2 221. Very hard lime rock and flint 2298 2300 2 222. Hard lime and flint rock (six days' drill- ing) 2300 2307 7 223. Very hard limestone and flint rock 2307 2312 5 224. Very hard blue lime rock 2312 2322 10 225. Hard blue lime rock. 2322 2329 7 226. Red sand rock 2329 2331 2 227. Hard blue lime rock 2331 2333 2 228. Very hard blue lime rock 2333 2343 10 229. Very hard blue lime rock, almost flint 2343 2348 5 230. Hard limestone 2348 2382 14 231. Hard blue limestone 2362 2381 19 232. Blue limestone 2381 2383 2 233. Hard limestone 2383 2392 9 234. Red sand rock and limestone. 2392 2395 3 235. Blue limestone 2395 2396 1 236. Red sandstone and blue limestone. 2396 2401 5 237. Blue limestone 2401 2413 12 238. Very hard limestone 2413 2416 3- 239. Blue limestone 2416 2429 13 240. Hard limestone 2429 2442 13 241. Blue limestone 2442 2450 8 242. Lime and red sand rock — : 2450 2466 16 243. Hard blue sand rock 2466 2472 6 244. Blue sandstone and limestone 2472 2480 8 245. Limestone 2480 2487 7 246. Blue limestone '. 2487 2535 48 247. Red sandstone and limestone 2541 2551 10 16 Bulletin of the University of Texas 248. Limestone 249, 250. Feet below •surface. Thick- From. To. ness. 2551 2560 9 Blue limestone 2560 2599 39 _„„ Lime and red sandstone 2599 2612 16 251. Blue limestone 2612 2622 10 252. Lime and blue sandstone. 2622 2640 18 253. Blue sand and red sand rock 2640 2653 13 254. Red sand and lime rock 2653 2664 11 255. Soft red sand rock 2664 2673 9 25i6. Blue limestone 2673 2677 4 257. Blue shale 2677 2682 5 258. Limestone 2682 2685 3 259. Blue sand rock, very hard 2685 2694 9 260. Blue sand rock 2694 2701 7 261. Lime and brown sand rock 2701 2716 15 262. Hard brown sand rock 2716 2735 19 263. Brown sand rock 2735 2744 9 264. Soft gray sand rock, hard streaks 2744 2751 7 265. Brown sand rOck, hard 2751 2802 51 266. Brown sand rock_ 2802 2969 167 267. Hard brown sand rock 2969 2975 6 268. Very hard brown sand rock and flint 2975 2980 5 269. Anhydrite, water seep 2980 2995 15 270. Limestone - 2995 3045 50 271. Anhydrite 3045 3046 1 272. Limestone 3046 3060 14 273. Hard blue shale with streaks of lime 3060 3075 15 274. Streaks of anhydrite and hard limestone 3075 3125 60 275. Limestone, hard 3125 3141 16 276. Limestone 3141 3180 39 277. Brown limestone 3180 3185 5 278. Limestone 3185 3200 15 279. Limestone and anhydrite 3200 3205 5 280. Limestone 3205 3210 5 281. Limestone, very hard 3210 3215 5 282. Limestone 3215 3240 25 283. Limestone and anhydrite 3240 3245 5 284. Limestone 3245 3255 10 285. Brown limestone .. 3255 3260 5 286. Limestone 3260 3280 20 287. Brown limestone 3280 3290 10 288. Limestone ._ 3290 3320 30 289. Limestone :- 3320 3340 20 290. Brown limestone 3340 3345 5 The Deep Boring at Spur 17 Feet below surface. Thick- From. To. ness. 291. Limestone 3345 8350 5 292. Brown limestone 3350 3355 5 293. Limestone 3355 3363 8 294. Very hard brown rock 3363 3371 8 295. Limestone 3371 3512 141 296. Very hard limestone 3512 3521 9 297. Very hard brown limestone 3521 3540 19 298. Limestone 3540 3667 127 299. Blue shale 3667 3669 2 300. Limestone 3669 3752 83 301. Very flinty limestone 3752 3763 11 302. Hard limestone 3763 3791 28 303. Limestone 3791 3842 51 304. Brown and hard limestone 3842 3850 8 305. Very hard limestone 3850 3858 8 306. Limestone 3858 3926 68 307. Hard limestone and some pyrite 3926 3932 6 308. Limestone with lot of pyrite 3932 3947 15 309. Very hard limestone and pyrite 3947 3952 5 310. Limestone 3952 3964 12 311. Brown limestone with pyrite 3964 3975 11 312. Limestone 3971 3986 15 313. Limestone with pyrite 3986 3994 8 317. Limestone 3994 4020 26 318. Hard limestone 4020 4045 25 319. Limestone 4045 4075 30 320. Very hard limestone 4075 4076 1 321. Limestone and anhydrite 4076 4088 12 322. Gray limestone -- 4088 4152 64 323. Very hard limestone 4162 4168 16 324. Limestone 4168 4215 47 325. Hard limestone 4215 4218 3 326. Limestone -. 4218 4263 45 327. Brown limestone 4263 4278 15 328. Limestone 4278 4288 10 329. Gray limestone 4288 4305 17 330. Limestone 4305 4325 20 331. Very hard limestone 4325 4332 7 332. Hard limestone 4332 4350 18 333. Limestone 4350 4389 39 334. Limestone and' shale 4389 4398 9 335. Limestone, streaks, dark shale 4398 4407 9 336. Dark shale and limestone 4407 4431 24 18 Bulletin of the University of Texas Feet below surface. Thick- From. To. ness. 337. Dark shale with streaks of limestone 4431 4470 39 338. Limestone and dark shale 4470 4475 5 339. Limestonef . 4475 44/79 4 340. Limestone and shale 4479 4489 10 EXPLANATION OF TERMS USED The above record was kept in five standard diary books for the years the work was in progress by Mr. H. P. Minihan, the driller. In these he recorded not only the depth bored each day and the nature of the rock on which the drill was working, but also generally the hours of time consumed in actual drilling, the kind of bit used, and the many other operations incident to the actual drilling. All these records have been generously submitted to the writer. Mr. Minihan's record of the strata penetrated has been copied from his notes practically verbatim, with the mere elimination of repetitions incident to the making of daily entries. Though being a driller of wide experience, Mr. Minihan had not worked in the Red Beds previous to his engagement at Spur. A few notes on the descriptive terms used in his entries may not be amiss. "Isinglass" is frequently used in the southwest for gypsum, especially when it is in the pure crystalline form of selenite. It is evident that the term is thus used here. "Gumbo" is "clay which adheres to the bit." The red: clays so designated in this record had the same property, and they seem to have been marly. "Flinty," as used in the uppermost 1000 feet of the record, has refer- ence to compactness of texture in anhydrite, except in num- ber 9, where there were some flint and quartz pebbles. The compactness, the gray color, and the conchoidal fracture of some of the close-grained anhydrite gives to this rock a notable optical resemblance to flint, and chert, as this ap- pears in the Edwards limestone and other parts of the Comanchean. Between 1600 and 2000 feet it is believed the descriptions "flinty rock," "flint rock," "flint," and "sand The Deep Boring at Spur 19 flint," often refer to concretions and layers of tough chalce- donic quartz, which occur in association with anhydrite in some of the limestone penetrated. In number 211 and presumably in some preceding entries, the word "flint" is to be understood in its usual sense, as is shown by the samples. Between 2210 and 2200 feet below the surface, there was a siliceous dolomite, dark in color, which was very resistant to the drill. This may probably be most correctly described as a chert. In some other cases, the significance of the term flint is not so evident. Throughout most of the first 2000 feet of this record the qualifying word "hard" is generally used to denote moderate induration in distinction from the soft unindurated state of such rocks as sand,, clay, marl and shale. Especially is this true when the term is applied to limestone. "Very hard" is then used to describe more than normal hardness. When used to describe sandstone and shale, the term "hard" is evidently used to distinguish particular strata of these sediments from others of the same kind which were less Indurated. In this sense it appears to be used also when applied to limestone in the last 2000 feet of the section. "Flint sand" and "sand and flint rock" are two unusual and, in one sense, contradictory terms describing a somewhat unusual kind of rock, consisting of dolomite, into which have been introduced anhydrite and some siliceous material. It is believed that the oolitic character of part of this lime- stone has naturally caused it to be classified as sandstone or sand rock. This appears to be the case with the sand- stone in number 212, and it may explain some of the differ- ence between the driller's record and the samples described from between 2800 and 3050 feet in the section. METHODS AND RATE OF DRILLING The drilling was performed by a rotary machine from beginning to end. Down to 2307 feet the fish-tail bit, the core-barrel bit, the square bit, and the diamond-shaped bit were used; the two latter were used only when very hard ground was encountered, or when some obstruction had to 20 Bulletin of the University of Texas 1273-1280, 1369-1370, 1806-1810, be worn away. Below 2307 feet the roller bit was used, being found much superior, when in order, to other bits for drilling in limestone or other moderately hard rock. Coring was done for the following depths (in feet below surface): 913.5-963, 969-1033, 1035-1053, 1055-1068, 1082-1143, 1151-1169, 1225-1250, 1253-1270, 1284-1287, 1288-1309, 1313-1320, 1331-1331.5 1494-1510, 1525-1558, 1566-1627, 1705-1713, 1827-1830, 1838-1845, 2244-2255, 2256-2264. The deepest run for a day with the fish-tail bit was 57 feet, at the depth of from 225 to 282 feet; the next three highest runs were 56 feet, from 121 to 187 feet; 38 feet, from 187 to 225 feet; and 36 feet, from 2071 to 2107 feet. These speeds were in soft red sandstones and shales, containing some small beds of gypsum. The slowest drilling was in strata containing flint and other concretionary quartz, where the speed was reduced to from six inches to a foot for a day's continuous work. From Mr. Minihan's notes it appears that the average depths drilled in a day of eight hours, by different drills, was about as below, for the differ- ent rocks explored : Average Rate of Drilling in Different Rocks and by Different Drills, in Feet per Day Soft sand- stone and sandy clay tihale Limestone Hard sandstone Flint beds Roller bit IS 20 10 5 6 3 2 Fish-tail bit 20 1 STUDY OF ROCK SAMPLES To properly interpret the driller's section, some 330 samples of drillings and pieces of core have been examined. Thin sections were made of some 200 rock samples, nearly all dolomite, limestone and anhydrite, and notes were taken on a number of minute fossils found in the cuttings of lime- stone and shale mostly in the lower 2400 feet of the well. The Deep Boring at Spur 21 Taking of the Samples The number of rock samples which have been examined is 330. The first fifty-eight of these were cuttings selected by the driller to represent the several strata explored in the first 914 feet. From this depth down to 1174 feet, the sam- ples are mostly broken pieces of core similarly selected. From 1174 to 1250 feet no more than two samples of cuttings represent the ground penetrated. From 1250 to 2042 feet there were only five samples taken from depths definitely known, but there are four more samples known to have come from somewhere between these two depths. All are pieces from cores. From 2042 to 8050 feet the section is represented by 48 samples, some of which are selected to represent the formations, and some not thus selected. From 3050 feet down to the bottom came 202 samples, which are cuttings taken quite regularly every five or ten feet, irrespective of the nature of the rock drilled. Mixing of Returns in Rotary Drilling It is sometimes urged that the identification of strata explored by examination of cuttings in rotary drilling is impossible, on account of the mixing of the returns. This is not at all the case. In the first place, no rock can appear in the returns before it has been entered. There is no possibility of the mixing in of any accidental foreign in- gredient except from above. Examining the samples in the order from above downward, the upper formations are known and are usually easily recognized. When mud is prepared and used to support the walls in case of soft ground, the case is different, of course. Mixing of returns increases with depth and an extreme case can be gauged in the lower part of this well after it was cased down to 3044 feet. The finest material silts out very tardily in the mud pool, and may remain in circulation no doubt for sev- eral days. But the old fine mud is continually diluted and replaced by new fine material. The coarser material con- sisting of particles a half millimeter or more in diameter 22 Bulletin of the University of Texas settles in the reservoir more promptly, and at the average rate of drilling it practically disappears from the cuttings in from ten to thirty or forty feet, even at a depth of 4000 feet. Thus it will be seen that brown limestone reported at from 3964 to 3975 feet disappeared from the drillings below the depth of 3990 feet. The white limestone which first ap- peared in the drillings at 4095 feet had mostly disappeared at 4145 feet. In this latter case, it is possible that the transition from dolomite to limestone was itself gradual, or intermittent. From 4152 to 4163 the driller reports very hard limestone, and it is evident that the slow drilling at this depth was due to chert, which appears in the drillings promptly from 4150 to 4155 feet and continues in the sample taken at 4160 to 4165 feet. The more slow the drilling, the purer is the sample. Fine sand consisting of grains more or less rounded is apt to stay with the silt in circulation. The driller reports in this boring a red sand rock at 2541 to 2551 feet, and again at 2640 to 2653 feet. Some red sand grains are present in most of the material from between these depths. Shaly admixtures show greater irregularity, owing no doubt to caving. But this affects the samples taken from other than rotary drilling as well. In the case of a shale reported at from 3060 to 3075 feet in the present instance, an increase in the shale in the returns began at 3070 feet and there was a noticeable diminution at 3080 feet. The essential reliability of the samples in the present case is evident from a comparison of the section as made out from the cuttings with the speed of the drilling. Wherever chert, or flint, appears in the cuttings, drilling was slow ; while, in case where shale and some sandstone appears in the returns, the work was most rapid. (See Plate 13.) Descriptions of Samples Descriptions of the samples have been made as full as possible in the hope that when we shall have a more detailed knowledge of these formations from their outcrops, it may be possible to make correlations with greater confidence and precision than is possible at the present time. The Deep Boring at Spur 23 Feet From. To. 1. Soil 2 2. Sub soil 2 6 3. Pinkish yellow sand 6 16 4. Gravel 16 23 5. Brown sand 23 27 6. Bright red marl 27 53 7. Red marl and gravel 53 65 8. Gypsum and red clay 65 75 9. Red sandy shale, crystalline and fibrous gyp- sum, some limestone, fragments of quartz and chert pebbles. The shale shows some light blue spots 10. Red clay and red sand of fine texture 11. Gypsum 12. Gypsum 13. Red sandy shale .. 14. Gypsum 7S 85 85 98 98 101 101 108 108 115 115 119 119 135 149 153 153 192 192 199 199 221 15. Red sandy shale 16. Brown sandy shale, blue shale, and much gyp- sum ;.: 135 137 17. Red sandy shale. Some shale shows blue cir- cular spots % mm. in diameter 137 18. Red sandy shale and gypsum 19. Red sandy shale and gypsum 20. Gypsum :. 21. Red marl 22. Crystalline gypsum, structureless gypsum, and some red shale 221 223 23. Red marly clay or shale, most particles meas- uring from 0.001 to 0.04 mm. in diameter 223 239 24. Crystalline gypsum 239 254 25. Soft red sand of fine texture, with some cal- careous material 254 272 26. Bright red clay, calcareous 272 285 27. Compact anhydrite and some white gypsum, and red shale 285 298 28. Deep red sand of fine texture 298 330 29. White, compact, or finely granular anhydrite.;.. 330 403 30. Gravelly and well-worn sand, red limestone, and sandy shale, with gray chert. This sample contains some small crystals of anhydrite, some lumps of anhydrite and a few scales of gypsum 31. Red sand of fine texture 32. Sand, clay, and anhydrite 403 468 468 532 532 538 24 Bulletin of the University of Texas Feet From. To. 33. Red and gray sand, with white fine-grained and tough and hard anhydrite and red gran- ular limestone 538 540 34. White tough anhydrite , 540 568 35. White, tough and close-grained anhydrite 568 570 36. Salt, finely granular, mixed with (1-20) fine red sand and silt, and showing laminations of the thickness one-half to two mm 570 580 37. Worn quartz sand from 1 to % mm. in diame- ter, and some anhydrite in entire granular crystals 580 586 38. Anhydrite of fine granular texture, pink, red, and white, with some red sandstone having white blotches 586 596 39. Mostly quartz sand. Also red silt and clay. Calcareous fragments, black, white and red 596 603 40. Tough, compact, white anhydrite 603 624 41. White anhydrite, some finely granular, some more compact in texture 624 628 42. Red sand and silt, with much calcareous ma- terials. Crystals of anhydrite and quartz noted 628 633 43. No sample. Driller reported salt 633 638 44. Silty red sand with light gray spots and blotches, and containing small particles of anhydrite, calcareous 638 645 45. Red sand and clay with some calcareous ma- terial 645 674 46. Quartz sand, coarser and clearer than the aver- age in preceding samples 674 688 47. Red sand of fine texture, with red silt 688 715 48. Red sand of fine grains 716 725 49. Anhydrite, compact, bluish white . 725 732 50. Salt, transparent and crystalline, but clouded with blotches of red silty material 732 741 51. Dark red silty sand, and some coarse sand with some compact anhydrite. Crystals of quartz, anhydrite and gypsum noted 741 773 52. Anhydrite, showing cracks and joints, mostly white, some pink 773 778 53. Red sand of fine texture. Crystals of anhy- drite and quartz noted 778 804 54. Dark red sand, shale and clay, with thin folia- tions of gray anhydrite 804 812 The Deep Boring at Spur 25 Feet From. To. 55. White, irregularly finely laminated anhydrite. A sample from this depth was ground to powder, very fine, by the bit. This powder stuck to bit, and dried (set) to a hard cake, almost pure white. This was sulphate of lime, mostly gypsum, containing much water 56. Red sand of moderately fine texture.. 57. White anhydrite of fine texture.. 812 816 816 853 853 858 858 914 58. Red sand, with some clayey material 59. Red, fine-grained safidstone, with gray spots, and containing 20 per cent salt (no potash) and a red rock consisting of 67 per cent of salt and 33 per cent sand. The salt is crys- talline, showing large crystalline surfaces with continuous reflections. The salt and sand are very evenly mixed 914 931 63. A dark brown rock consisting of 68 per cent silt (none of silt above % mm. in diameter of grains) and 40 per cent of salt. The silt has the fineness of loess. Rock is laminated 931 932 61. Gray compact anhydrite, in a separate sample from 931 62. Crystalline salt and fine red sand 950 1000 63. A dark brown rock consisting of 69 per cent of silt, and 32 per cent of salt. No potash. The silt is of about the fineness of loess. Con- tinuous reflections of the crystalline salt were noted 958 962 64. Granular anhydrite, with grains about % mm. in diameter. This contains scattered sub- angular grains of quartz, about % mm. in diameter, and some grains of a green min- eral, in a separate sample from ... 992 65. A brownish red rock consisting of 50 per cent of red sand and 50 per cent of salt. Test for potash negative 962 1113 66. Gray, close-grained anhydrite, containing some salt, was noted in a sample from 1005 67. A laminated, close-grained, gray and grayish pink anhydrite, containing from 5 to 8 per cent of salt, no potash, and some siliceous silt. It contains no limestone. Some grains of a green mineral were noted 1113 1117 26 Bulletin of the University of Texas Feet From. To. 68. A blotchy brown and gray close-grained rock showing reflections of halite. It contains 37 per cent of salt. No potash. The rest is sand and silt -— 69. A close-grained bluish gray anhydrite, quite free from impurities. No reaction for lime- stone 1117 112a 1123 1125 70. A red, sandy and silty rock, showing mica scales in some seams and reflections of halite on some fractures vertical to the indistinct lamination. It contains 30 per cent of salt, and the insoluble material is in part siliceous sand and silt, and contains some anhydrite — 1125 1174 71. Fine sand and silt and some calcareous frag- ments, black, white, and red, evidently from concretions. Some anhydrite. The rock loses about 15 per cent by solution in cold water. The rock also contains some coarse quartz sand, well rounded. Some chert noted. No potash 1174 1222. 72. Brown sandy silt, with some larger fragments of limestone or calcerous concretions. Some anhydrite. No potash 1222 1235 73. Mostly white and gray anhydrite, mixed with a few calcareous fragments and much red sand and silt. Crystals of anhydrite and gypsum noted 1235 1250. 74. From between 1250 and 2042 feet below the surface came several pieces of cores, from depths not specifled, as follows: (1) A part of a large septarian concretion. It shows two Assures at right angles filled with an- hydrite, calcite and pyrite. The matrix be- tween these Assures consists of a dark grray, very compact material, effervescing slowly in acid, but not slacking in water after ex- posed to reducing flame, nor becoming mag- netic. (2) Two pieces consist of dark gray, impure limestone, stratified. One is ob- scurely oolitic, the other is an oolitic' fine- textured organic breccia, in which an apex of a gastropod, some bryozoans, and foram- inifera were noted. (3) A siliceous dolo- mite, dark gray, effervescing slowly, thinly laminated, laminae about 89 in one inch. The Deep Boring at Spur 27 Feet From. Seen in vertical section, the laminae are ir- regular, turning in small abrupt bends so as to frequently diverge, converge and end at ir- regular intervals. In places, they turn around small imbedded granules. The lami- nae are marked by black, very thin folia, which are separated by thicker layers of transparent material. The rock gives fumes of bitumens and sulphur when heated in a closed tube. Plate 1, B. (4) A dark gray dolomite of fine texture. In thin section it isi seen to consist of fine oolitic material, To. Figure 1. Impure oolitic and concretionary dolomite. From be- tween 1250 to 2042 feet below surface. Part of the rock is replaced by anhydrite. A.A. Matrix of the concretionary rock, showing crystals of dolomite 0.01 mm. in diameter. B.B. Minute concretions imbedded in the matrix and having a fine texture. C. Trace of a fossil in the original rock, shown by a smoothly curving zone of crystals of larger size than the prevailing crystals in the matrix. D. D. Crystals of anhydrite replacing part of the matrix and parts of concretions^ Magnified about SO diameters. 28 Bulletin of the University of Texas Feet From. To. the spherules being slightly less than 1 mm. in diameter, oval and spherical. With these are mingled many organic fragments. Some otf these are thin fragments of ostracod shells, minute fragments of bryozoa and f oraminif era, apices of gastropods, and tubu- lar structures. One of the foraminifera has biserially arranged chambers. In one sec- tion a perforate test was noted. Plate 1, A 1250 2042 75. Gray, close-grained anhydrite, at 1590 76. A dark gray dolomite limestone with cherty layers. There are alternate layers of darker and lighter gray, the darker being the more siliceous. In thin section the rock is seen to Figure 2. Section of rock somewhere from 1250 to 2042 feet be- low the surface. Dolomitic oolite containing imbedded shells of ostra- cods, gastropods, foraminifera. Slight impregnations of bituminous material give a brown tinge to many of the spherules and organic frag- ments. The matrix in which the spherules are imbedded is more coarsely crystalline than the spherules themselves. See Descriptions of Samples 74 (4). X about 30. The Deep Boring at Spur 29 Feet Prom. To. consist of a matrix of minute dolomite crys- tals. Among these there are larger ob- scurely outlined, elongated bodies which are siliceous. Some of them have a faint re- semblance to sponge spicules, being straight. The others are more like small fragments of thin shells, broken so as to be about twice as long as thick. Along some planes in the rock are small cavities filled with chalcedonic quartz. These cavities are mostly spherical and from less than >^ to 1 mm. in diameter. The chalcedony shows imbedded rectangular bodies which have a tendency to lie end to end, in irregular chains. The rock shows minute black streaky stains, probably manga- nese. This sample is doubtfully labeled as coming from 1600 Figure. 3. Vertical section of siliceous dolomite from somewhere between 1250 and 2042. See Descriptions of Samples, 74 (3). X about 40. 30 Bulletin of the University of Texas Feet From. To. 77. Gray magnesian limestone of fine texture. It is porous and when ground dry has a slight bituminous odor. In thin section it is seen to be a finely crystalline dolomite, filled with porosities, angular or spherical. As there was much salt on the surface of the speci- men, it seems likely that these porosities had contained the salt. Plate 2. From 1600 78. A section from rock at 1800 feet consists of an oolite matrix, dolomitized, in which are in- cluded crystals of anhydrite, which consti- tute one-half of the mass, nearly, and have replaced the oolitic matrix. This closely resembles the other oolitic rock, from 1250- 2042 feet, described above. Plate 3 1800 79. A dolomitic limestone of fine texture, contain- ing spherical pockets of anhydrite in small crystals of irregular arrangement. The crystalline texture in the dolomite exhibits a grouping which indicates clastic or oolitic structure in the original rock. Black streaks - and particles of marl, apparently, are nu- merous. Imbedded straight sponge spicules ;gre also,, seen in placed, in the arrangement of the crystals of the dolomite 1 1810 1870 80. Blue shale, effervescing slowly in acid. . There are some white fragments which consist of a tangle of slat-like crystals. This rock gives '■^ trace of potash.„ 2042 2047 81. Fine sand, red, mixed with gray shale and an- hydrite. At red heat the shale gives very strong fumes of sulphur ......... 2047 2049 82. Soft, shaly limestone, dove-colored......_ 2049 2063 83. Gray, purple and red anhydrite \yith some •.brown shale and a few grains of red and white limestone 2064 2068 84. Deep brown, highly ferruginous and slightly micaceous, sandy shale, and dark gray, soft anhydrite-bearing dolomite. Sample gives a trace of potash 2068 2110 85. Soft gray dolomite, and some gray shale 2110 2127 86. Dark red clay, containing some fine mica and very fine sand 2128 2212 The Deep Boring at Spur 31 Feet From. To. 87. A thinly, curvingly_ laminated gray dolomite with red sandy shale, and anhydrite. Also gray shaly dolomite 2212 2214 ■88. Gray dolomite and some almost black and greenish gray calcareous shale, with a few large and rounded quartz sand grains. Some white quartz present. Some white calcareous grains and some brown shale. The black shale contains small angular crystalline par- ticles of anhydrite, gives fumes of oil and sulphur in closed tube 2214 2219 ■89. Gray dolomite. No flint noted. Much anhydrite and some red silt 2219 2241 ■90. A light gray dolomite of fine texture, very soft. In thin section it is seen to consist of uni- formly small crystals of dolomite. There are some very thin black lines, probably bitumi- nous. These follow the bedding planes in broken irregular curves. The core contains a concretion of anhydrite, some three inches in diameter, imbedded in the rock. This con- cretion partly is lined externally by a layer of white quartz and it also contains nodules of quartz internally. The rock yields fumes of bitumen, sulphur and ammonia when heated in closed tube. Plate 4, A__. 2250 '91. Five fragments of rock weighing from 5 to 10 grams each. One is a laminated gray dolo- mite of fine texture. Two fragments are' gray chert. One is apparently from septaria, showing vein material of gypsum and pyrite one-fifth of an inch thick, on two surfaces at oblique angles to each other. One f ragn^ent consists of anhydrite, showing black cloudy specks 2241 2271 '92. A dark gray impure dolomite, soft, and break- ing like shale; shows fine but obscure lamina- tion and shows grouping of crystals indi- cating original organic fragmentary struc- ture. Several concretions of chalcedonic quartz noted, from one-fourth to one inch in diameter. This rock contains some salt.,.. 2244 2264 32 Bulletin of the University of Texas Feet From. To. 93. A gray fossiliferous oolitic dolomite. A small lamellibranch, a spiral shell of small size, and a bryozoan were noted ; under hand lens some small bryozoa were noted and the en- tire rock was seen to consist of a matrix in which there are imbedded round and oval bodies of variable shape, like oolitic spher- ules. Nearly, all of these show an outer limiting crust. Most of them are from one- sixth to one-half mm. in diameter. Some are several times as long as broad, and one showed a row of internal chambers. Some are clearly foraminifera. Heated in closed tube, bituminous fumes are produced. Plate 5 2250 2264 94. A light gray dolomite of fine texture, and soft. It contains concretionary structures of lighter gray. In thin section many brown- ish dark streaks of bituminous matter are seen and scattered small pockets of anhy- drite. In a concretion some light specks and straight crystals are seen. These are prob- ably quartz. In closed tube it distils oil and gas. Taken at 2260 95. Oolitic dolomite, containing much secondary an- hydrite. Plates 6 and 7 2264 96. Gray dolomitic shale and shaly limestone, con- taining fragments showing a tangle of slat- like crystals like those at 2042-2047 feet be- low surface. Obscure fragments of shells. A thin horizontal section shows some small circular areas of more compact dolomitic ma- terial 2271 2329 97. Like the preceding, but with more anhydrite and gypsum 2329 2331 98. White granular anhydrite and gray anhydrite.. 2331 2336 99. Brown, gray and white granular anhydrite. No sand noted 2336 2338 100. Mainly white granular anhydrite with some light gray dolomite. In thin section this dolomite is seen to consist of crystals less than 0.01 mm. in diameter, among which are scattered crystalline bodies of anhydrite of larger size 2338 2392 The Deep Boring at Spur 33 Feet From. To. 101. Black shale, some red sandy and micaceous silt, some gray shaly dolomite. The black shale emits bituminous and sulphurous fumes when heated in a closed tube 2392 2394 102. White and gray anhydrite, mostly. A frag- ment of anhydrite contains streaks of finely granular dolomite and a fragment of dolo- mite contains angular particles of anhydrite 2394 2454 103. Mostly white granular anhydrite. A part of the sample is a red silt, slightly calcareous. A few quartz grains were noted, small, angu- lar and rusty 2454 2460 104. Gray dolomite containing scattered grains of anhydrite and cavities from which the an- hydrite has been dissolved, probably. Some red silt and quartz grains noted 2460 2476 105. White and gray anhydrite and some greenish shaly limestone and shale, dolomitic 2476 2539 106. Mainly anhydrite. A dolomitic oolite in which the texture is obscured by the process of dolo- mitization and by a partial replacement of the dolomite by anhydrite. Much anhydrite and a few grains of rusty quartz sand present 2539 2545 106a. Mostly white anhydrite and some gray dolomite 2545 2606 107. Gray, soft dolomite and much anhydrite. In thin section the limestone is seen to be an oolite, containing much anhydrite. Some red shale and rusty quartz grains present 2606 2609 108. Gray dolomite, consisting of oolitic oval spher- ules. Both matrix and spherules contain nearly one-half their bulk of introduced an- hydrite. The spherules have sharply de- fined outlines and measure 0.2 mm. in diam- eter 2609 2624 109. Gray, soft dolomite and anhydrite, with some red sand grains 2624 2644 110. Red clay, red quartz sand, and some limestone 2644 2660 111. White anhydrite, with a few fragments of gray, soft dolomite 2660 2664 112. Red clay and silt and brown and gray anhy- drite, and quartz sand 2664 2673 34 Bulletin of the University of Texas Feet From. To. 113. Light bluish gray and soft dolomite containing much introduced anhydrite. Some red clay and sand. One fragment shows clusters of spicular structures, probably from sponges. Plate 9, A 2673 2677 114. A rock which consists of variable ratios of gray dolomite and anhydrite, with some red sand, some shale, and some red anhydrite. The outlines of a chain of chambers of a Nodosaria (?), composed of dolomite crys- tals are preserved in a matrix of anhydrite in one fragment 2677 2682 115. Gray and blotched white anhydrite in slender crystals of roughly fascicled arrangement 2682 2685 116. Eed shale and gray dolomitic limestone. Some of the latter is of uniformly fine texture, some contains many imbedded crystals of anhydrite. Some dolomite shows traces of oolitic structure. Bituminous matter pres- ent in streaks in the rock 2685 2698 117. Yellowish gray, bituminous dolomitic limestone, containing many clear crystals of anhydrite and yellow streaks of bituminous matter. Distils oil in closed tube and also ammonia 2698 2709 118. Light and dark, gray dolomite. The dark frag- ments effervesce most slowly. In some of the dark fragments is clear anhydrite, fill- ing oolitic spherules and foraminifer tests. Some red shale. Plate 9, B 2709 2735 119. Dolomitic limestone and fine yellow quartz sand, mostly from 0.25 mm. to 0.06 mm. in diameter. The grains have a thin coating of red oxide of iron and are not thoroughly rounded. No foraminifera seen in the lime- stone, but traces of other organic forms noted. Gypsum, pyrite, and anhydrite seen 2735 2751 120. Dark gray and light yellow oolitic dolomite, some coarse and rounded quartz sand, and some red shale. Some of the limestone con- tains clear anhydrite in a matrix of uni- formly fine crystalline dolomite. Pyrite noted, and gypsum 2751 2900 121. Gray dolomite. Under the microscope it is seen to be traversed by anhydrite. Some light colored fragments consist of minute round The Deep Boring at Spur 35 Feet From. To. lumps of a micro-crystalline dolomite in- cluded in a copious matrix of anhydrite. One fragment is clearly an oolite, with a matrix of anhydrite. Others are altered oolitic dolomite with spherules less well preserved 2900 2950 122. Like the preceding, with obscure traces of fos- sils 2950 2956 123. Rock like the preceding. No traces of fossils noted. Minute gypsum crystals noted 2956 2980 124. White anhydrite. 2980 2995 125. A bluish gray dolomite with black minute streaks, with small pockets and concretions of anhydrite. In thin section the body of the rock is seen to consist of small crystals of dolomite among which are brown streaks, and some angular and other cavities filled with anhydrite. Some faint curving marks resemble traces of fossils 2987 3002 125a. Yellow oolitic limestone and yellow dolomite of compact texture, showing oolitic spherules and thin imbedded fragments, probably or- ganic. There is some gray sandy shale and some anhydrite. Some dolomite contains an- hydrite, replacing a part of the original rock 2995 3050 126. Anhydrite and gray dolomite. The dolomite consists of crystals of uniform size, about 0.008 mm. in diameter. It contains black and rusty red specks and streaks. The specks are much smaller than the crystals 3044 3046 127. Dark greenish gray shale, and some yellowish gray dolomitic limestone 3046 3050 128. Gray oolitic dolomite. Some spherules have the outlines of organic fragments. Introduced anhydrite present 3050 3055 129. Yellowish gray dolomite, somewhat compact in texture 1 3055 3058 130. Yellowish gray dolomite and greenish shale 3058 3060 131. Dark shale, of conchoidal fracture and fine ho- mogeneous texture, slightly calcareous. With this is a concretion of anhydrite of an oblate spheroid shape, nearly an inch in diameter — 3060 3065 132. Dark shale and some yellow dolomite 3065 3070 133. Greenish dark shale, with some fragments of yellow doloniite 3070 3075 36 Bulletin of the University of Texas Feet From. To. 134. Dark shale, yellow dolomite, anhydrite and gypsum 3075 3080 135. Dark shale and anhydrite, with fragments of yellowish gray dolomite 3080 3085 136. Greenish gray shale, dark shale, and anhydrite 3085 3090 137. Green shale, dark shale, some yellowish gray dolomitic rock, effervescing somewhat rap- idly for a dolomite. The green shale has minute dark curving streaks 3090 3095 138. Dark shale, a compact yellowish gray dolomite, and anhydrite 3095 3100 139. Dolomite, anhydrite and shale 3100 3105 140. Anhydrite and dark green shale, with some dolomite 3105 3110 141. Dark green shale, with some yellow dolomite and some anhydrite 3110 3115 142. Yellowish dark gray dolomite of marked oolitic texture and with a matrix containing intro- duced anhydrite. Much dark green cal- careous shale 143. Shale and dolomite 144. Like the preceding 3115 3120 3120 3125 3125 3130 3130 3135 3135 3140 145. Dark greenish gray shale and compact yellow dolomite with some anhydrite 146. Like the preceding 147. Mostly dark shale and some brownish gray dolomite. The dolomite has secondary anhy- drite and shows traces of brecciated and oolitic texture in some fragments 3140 3145 148. Dolomite and shale. Dolomite has imbedded dark fragments, in part angular 3160 3155 149. Dolomite and dark shale. Dolomite effervesces slowly, is mostly yellowish gray, and mi- nutely brecciated in some fragments. It con- tains some secondary anhydrite 3155 3160 150. Mainly yellowish gray limestone, some of which is calcareous. Also some dark shale 3160 3165 151. Dark and light gray dolomite of uniform and compact texture and with secondary anhy- drite. In closed tube it distils oil 152. Like the preceding 153. Shale and yellowish gray dolomite. Some sand in a white calcareous matrix— i 154. Gray dolomite, with inclosed dark particles 3180 3165 3170 3170 3175 317S 3180 3180 3185 The Deep Boring at Spur 37 Feet From. To. 155. Dark gray dolomite with much secondary anhy- drite. An organic fragmental structure is indicated by the iilled mould of a shell frag- ment in one case and by the grouping of the dolomite crystals. Streaks of brown bitu- minous material present. Distils oil in closed tube 156. Like the preceding 157. Like the preceding . 3185 3190 3190 3195 3195 3200 158. Whitish dolomite, with imbedded minute darker fragments. Considerable anhydrite, green and dark shale. Pyrite in shale 3200 3205 159. Some dolomite containing secondary anhydrite, some oolitic dolomite with streaks of bitumi- nous material, and with structure showing traces of shell fragments, and some dark shale. A fragment of anhydrite contains many octahedrons of pyrite less than 0.02 in diameter 3205 3210 160. Dolomite of fine texture, containing small grains of a transparent mineral, probably anhydrite, evidently of secondary origin. Anhydrite fragments contains minute cubes of an opaque mineral 3210 3215 161. Dolomite and much dark green shale 3215 3220 162. Dark dolomite with some imbedded fragments of different shade. Bluish green shale 3220 3225 163. Some white rock, effervescing somewhat readily for dolomite. Also dark dolomite and green and dark shale 3225 3230 164. Dark green and dark gray shale and dolomite. The dolomite shows traces of oolitic spher- ules in some fragments and traces of irregu- lar fissures 3230 3235 165. Mostly dark green and black shale, with lime- stone as above 3235 3240 166. Like the preceding, with some anhydrite 3240 3245 167. Like the preceding, but with less anhydrite and more light gray dolomite. This dolomite has imbedded small lenticular bodies of darker dolomite, and is traversed by irregular bodies of anhydrite. Plate 10, A 3245 3250 168. Light gray dolomite, dark brown limestone, and much dark green shale 3250 3255 38 Bulletin of the University of Texas Feet From. To. 169. Dark dolomite, and dark shale . 3255 3260 170. Like the preceding ~ - 3260 d2b5 171. Very dark dolomite, with black and green shale 3265 6^10 172. Dolomite, thinly laminated, of som^ very dark and some almost white layers. Much shale.__ 3270 3275 173. Green and dark shale with dark and white dolo- mite 3280 3285 174. Shale and dark dolomite showing, in the group- ing of the crystals, obscure traces of clastic structure. Streaks of bituminous matter present. Distils oil in closed tube 3285 3290 175. Like the preceding. 3290 3295 176. Like the preceding, with some shaly gray lime- stone 3295 3300 177. Green shale and yellowish gray dolomitic lime- stone. The limestone contains minute cavi- ties of irregular form filled with anhydrite. The dolomite crystals vary in, size in spots, indicating original clastic structure, and fragments of organic forms 3305 3310 178. Like the preceding 3310 3315 179. Light gray dolomite of fine texture, like shale in appearance 3315 3320 180. Dolomite and greenish black shale 3320 3325 181. Dark green and dark gray shale 3325 3330 182. Dark greenish blue shale, and some dolomite. The dolomite is of coarse texture, crystals measuring 0.02 to 0.03 mm. in diameter. Some sharply limited "islands" of dolomite of fine texture occur in that of coarse tex- ture. Plate 10, B 3330 3335 183. Dark and greenish blue shale, gray and yellow dolomite. There is also some white anhy- drite. Some microscopic tubular (?) jointed fragments noted 3335 3340 184. Like the preceding 3340 3345 185. Mostly yellowish dolomite. Some white lime- stone, some dark shale 3345 3350 186. Some yellow dolomite, porous. In some frag- ments, black streaky layers were noted, both in this and the preceding sample. Greenish and dark shale. A grain of pyrite noted 3350 3355 187. Dark gray dolomite containing secondary anhy- drite and yielding oil when heated in closed tube 3355 3360 The Deep BoHng at Spur 39 Feet From. To. 188. Greenish gray shale and some almost black shaly, dark gray dolomite, and a few frag- ments of calcareous material 3360 3365 189. Mostly greenish gray shale, and dark gray shale 3365 3370 190. Dark gray shale, dark and light gray dolomite and some greenish gray shale 3370 3375 191. Dark gray and greenish gray shale, and gray dolomite 3375 3380 192. Like the preceding, but with less shale 3380 3385 193. Gray and dark gray dolomite, and dark gray and some greenish gray shale. The texture of the dolomite is coarse, the crystals meas- uring from 0.02 to 0.03 mm. in diameter. Some secondary anhydrite present 3385 3390 194. Light gray and dark gray dolomite and dark gray and greenish gray shale 3390 3395 194a. Light gray and straw colored dolomite and some greenish gray shale 3395 3400 195. Dolomite and shale. Some of the dolomite has coarse, some fine texture. The coarse has much secondary anhydrite. The fine-textured dolomite shows a grouping of the crystals into clusters of uniform size, 0.04 to 0.05 mm. in diameter. Plate 11, A ^___. 3400 3405 196. Like the preceding 3405 3410 197. Yellowish dolomite, gray dolomite, green hard shale and some gray shale 3410 3415 198. Yellowish dolomite, light gray and dark gray dolomite, and a small amount of limestone. Green shale and a small amount of gray and black shale. A small amount of anhydrite 3415 3420 199. Light and dark gray and yellowish dolomite. Some limestone. About one-third blue, dark, and green shale. Some anhydrite 3420 3425 200. Gray and yellowish dolomitic limestone, green- ish gray and black shale. Anhydrite is pres- ent, mainly in the fine material A very little limestone is present 3425 3430 201. Gray and yellow dolomite, dark limestone, green shale and some anhydrite, the latter mostly ground to very fine material. A very little limestone is present 3425 3430 202. Dark and yellow dolomite, some green shale. Anhydrite fragments were large in size in this sample 3435 3440 40 Bulletin of the University of Texas Feet From. To. 203. Gray and yellowish dolomite, green and black shale becoming less. Anhydrite present in the finer sizes of the sample 3440 3445 204. Gray, yellowish gray, and dark gray dolomite, and bluish green shale with some dark gray shale 3445 3450 205. Dolomite containing secondary anhydrite and shale of dark gray and green color. Some of the green shale shows dark streaks 3450 3455 206. Gray, dark gray and yellowish dolomite, and some dark gray and bluish green shale. 3455 3460 207. Like the preceding 3460 3465 208. Like the preceding. Dark shale slightly more abundant 3465 3470 209. Mostly gray dolomite, some dark gray dolomite, some yellow dolomite, some fragments of al- most black dolomite and only a little shale 3470 3475 210. Gray, white, yellow and dark g:ray dolomite, and greenish blue and gray shale 3475 3480 211. Gray, yellow and very light or white dolomite, and green and gray shale. A few calcareous fragments noted 3480 3485 212. Like the preceding. Some of the gray dolomite was seen to have dark gray blotches 3485 3490 213. Dolomite and shale. The dolomite contains some secondary anhydrite and shows traces of clustered tubular structures, 0.15 mm. in diameter. Plate 12, B 3490 3495 214. Like the preceding, in part. Some dolomite has crystals arranged in clusters 3495 3500 215. Gray, light gray or white, and yellow dolomite. The white and yellow dolomite is very com- pact. Dark gray and blue shale. The blue shale has minute microscopic dots, black 3500 3505 216. Like the preceding. Some more calcareous fragments 3505 3510 217. Like the preceding 3510 3515 218. Yellowish dolomite of very fine texture, crystals measuring less than 0.01 mm. Pockets of anhydrite occur and anhydrite fills some nar- row crescentic or half-annular spaces, be- lieved to be moulds of fossils. The mass of the rock shows distinct traces, in the group- ing of the crystals, of clastic structure 3515 3520 The Deep Boring at Spur 41 Feet From. To. .__ 3520 3525 219. Like the preceding 220. Dark gray blotchy dolomite, dark gray shale quite abundant. Some blue shale and white compact dolomite. Effervesence somewhat brisk for dolomite 3525 3530 221. Shale and dolomite in about equal quantities. Some shale is black 3530 3535 222. Much dark, black and green shale, interlami- nated in one fragment. Gray and yellow dolomite. Several calcareous fragments. Shreds of vegetation noted in one fragment of black shale 3535 3540 223. Mostly green and dark gray dolomite. Some shale, blue and dark 3540 3545 224. Dolomite and shale. The dolomite contains some secondary anhydrite. In the arrangement of its crystals a thin section of the dolomite shows obscure traces of tubular structures, 0.03 mm. in diameter, and also traces of small shells, probably ostracods. Plate 11, C 3545 3550 225. Mostly gray and yellow dolomite, some shale. One fragment of blue shale was seen to be very finely laminated with white. Pyrite noted in gray dolomite 3550 3555 226. Dolomite and almost as much shale. Some dark shale has imbedded bituminous shreds of vegetation, brown, translucent. One ob- long spore-like body noted 3555 3560 227. Blue and yellow shale and dolomite in about equal quantities. Considerable black shale 35i60 3565 228. Like the preceding 3565 3570 229. Mostly dolomite and shale of same appearance as in preceding sample 3570 3575 230. Dark gray dolomite, lighter dolomite and yellow dolomite. One fragment of shale was blue with shreds of black material imbedded. No sand noted 3580 3585 231. Like th^ preceding, but with more dark shale, and some calcareous material 3585 3590 232. Dolomite and shale. Shreds of vegetation noted in some of the dark shale. Pyrite noted in the dolomite 3595 3600 233. Bituminous dolomite, mostly gray. Dark and green shale 3600 3605 3620 3625 42 Bulletin of the University of Texas Feet From. To. 234. Dark dolomite and shale in about equal quanti- ties. Shreds of vegetation noted in dark shale. Some green shale noted. No sand seen. Yields oil in closed tube, and yields ammonia. Bituminous matter in irregular streaks and particles among crystals 3605 3610 235. Like the preceding. White dolomite absent, was present in the last preceding samples..- 3610 3615 236. Mostly gray minutely blotched dolomite, and dark gray shale, seen to be sometimes finely laminated 3615 3620 237. Dark gray shale, gray dolomite, some green shale 238. Dark gray minutely blotched dolomite, and dark gray shale. Some calcareous fragments present 3625 3630 239. Dolomite and shale. In the shale some minute flakes of mica were noted. In the dolomite are some straight and gently bending tubu- lar structures about 0.03 mm. in diameter. Some anhydrite present in the limestone 3630 3635 240. Dark dolomite and shale. Mica noted in shale. Calcareous fragments present, but scarce 3635 3640 241. Minutely blotched dolomite and dark gray shale. Calcareous fragments very few 3640 3645 242. Dark dolomite and dark shale. Calcareous ma- terial wholly absent. In thin section, obscure traces of clastic or concretionary, and of or- ganic structures were noted. Anhydrite present in small crevices, which are not well defined .. 3645 3650 243. Like the preceding. The dark dolomite was seen to have black streaks and imbedded black, minute lumps or grains. No sand present. Yields sulphur fumes... 3650 3655 244. Like the preceding with some coarse fragments of anhydrite 245. Like the preceding 246. Like the preceding 3655 3660 3660 3665 3665 3670 3670 3675 247. Dark and blue shale and dolomite 248. Dolomite and shale. In the dolomite is much secondary anhydrite which in its distribu- tion has left obscure traces of oolitic or clastic textures 3675 3680 The Deep Boring at Spur 43 Feet From. To. 249. Like the preceding. Both the dolomite and dark shale give off bituminous fumes in closed tube 3680 3685 250. Gray dolomite and dark gray shale. 3685 3690 251. Like the preceding. The dark dolomite is strongly bituminous in closed tube 3690 3695 252. Dark gray, minutely blotchy, bituminous dolo- mite and dark shale. The dolomite has im- bedded black grains. In closed tube gives trace of oil and fumes of gas. 3695 3700 253. Dark gray and yellow dolomite and dark shale. There is also some white anhydrite. The dark dolomite gives oil and strong bitumi- nous odors in closed tube. In thin sections, dark bituminous streaks are seen and the crystals are grouped in forms indicating or- ganic fragments i 3700 S705 254. Dark shale and dark bituminous dolomite as above 3705 3710 255. Black and green shale, dark gray dolomite. Both bituminous. Dolomite contains crys- talline anhydrite 3710 3715 256. Dark gray shale, dark buflp gray bituminous dolomite. In thin section the dolomite shows a profusion of organic fragments in dim outlines in the arrangement of crystals and inclusions of anhydrite 3715 3720 257. Dark dolomite, and green, gray to black shale. Heated in closed tube fumes of ammonia, sulphur, and bitumen are given off 3735 3740 258. Dark gray dolomite and dark . gray shale. Pyrite noted in dolomite. In thin section the rock is seen to have minute black streaks, and to be fine in texture, crystals measur- ing about 0.01 mm. in diameter. Driller's note-: "Unusually hard limestone." Am- modiscus noted. Bituminous fumes given off when heated in closed tubes 3755 3760 259. Dark dolomite and green, gray to black shale, which yields sulphur, oil and ammonia fumes in mattrass 3765 3770' 260. Dark dolomite and green, gray to black shale. One Ammodiscus noted. Ammonia fumes noted in closed tube. Distils oil and gas under same conditions - — 3775 3780 44 Bulletin of the University of Texas Feet From. To. 261. Yellowish to black dolomite, and greenish, gray to black shale. Sulphur and ammonia fumes given off when heated in closed tube. Am- modiscus noted, three specimens 3795 3800 262. Dark brownish gray dolomite and green and black shale. Fumes of oil, sulphur and am- monia are given off on heating in closed tube. Some anhydrite present 3810 3815 263. Dark gray dolomite, consisting of crystals 0.01 to 0.02 mm. in diameter and containing very little anhydrite. Black shale is present. The sample yields bituminous, sulphurous, and ammoniacal fumes when heated in a closed tube. Amraodiscus noted 3820 3825 264. Dark gray dolomite with some dark, some greenish and some black shale. On heating in closed tube oil, sulphur and ammonia fumes are given off 3830 3840 265. Dark grayish yellow dolomite and some green- ish and black shale. Flat Ammodiscus noted. Sulphurous, bituminous and ammo- niacal fumes are given off on heating in closed tube. In thin section some dolomite is seen to consist of crystals about 0.05 mm. in diameter, fairly uniform, some consists of crystals of variable size and clearness, giving indistinct outlines of original organic fragments, some being crescentic, and some fragments show bodies resembling oolitic spherules and encrusted organic fragments imbedded in a copious matrix of anhydrite,... 3850 3855 266. Mostly yellowish gray dolomite. In thin sec- tion some fragments show crystals quite uni- formly about 0.06 mm. in diameter. Two fragments consisted of crystals about 0.02 to 0.04 mm. in diameter, clustered in such a manner as to indicate that the original rock consisted of organic or other fragments. Some straight elonga-ted indistinct struc- tures were noted, resembling spicules of sponges. One fragment had many small cavities filled with anhydrite 3860 3865 267. Dolomite and shale 3g65 3370 The Deep Boring at Spur 45 Feet From. To. 268. Yellowish gray dolomite. In thin section one fragment is seen to consist of bodies of dolomite traversed and surrounded by tracts of anhydrite, and in another fragment there are pockets filled with anhydrite and also porosities in the rock 3875 3880 269. Yellowish gray dolomite. In thin sections three fragments were each of uniform sized crystals. In one these were about 0.02 mm. in diameter, another about 0.04, and an- other about 0.1. The finer textured speci- mens had the crystals in groups indicating some granular feature in the original rock. Pockets of anhydrite were noted in one sample, and also traces of spicular structure 3885 3890 270. Yellowish gray dolomite of coarse texture, and some dark shale. This shale was found to contain an Ammodiscus. Fumes of ammonia and sulphur noted on heating in closed tube 3900 3905 271. Yellowish gray dolomite and some black shale. Fumes of sulphur and ammonia are given off on heating in closed tube 3915 3920 272. Gray dolomite and some black shale. In thin section the crystals of the dolomite are seen to have a quite uniform size, about 0.04 mm. in diameter. Marks of some probable or- ganic structure like sponge spicules were noted. There were also distinct small crev- ices filled with what appeared to be anhy- drite. In closed tube, on heating, faint bitu- minous fumes were noted and stronger fumes of sulphur and ammonia... 3930 3935 272a. Dolomite and some black shale, pyrite noted 3935 3940 273. Yellowish gray dolomite and some green and dark shale. Fumes of oil, sulphur, and am- monia noted on heating in closed tube. Spicule noted in thin section^ 3945 3950 274. Yellowish gray dolomite and black and gray shale. Flint, yellowish in transmitted light, noted 3965 3970 274a. Like the following 3980 3985 275. Gray dolomite. In thin sections three frag- ments were seen to consist of uniform sized crystals measuring about 0.03 mm. in diam- eter. Some anhydrite was also seen in the 46 Bulletin of the University of Texas Feet From. To. thin section, occurring as fillings in irregular cavities. In one place it was clearly asso- ciated with red ferruginous material. The dolomite, when heated in tube, gives off faint fumes of bitumen, sulphur, and am- monia 39^5 ^^^^ 276. Dolomite and shale 3995 4000 276a. Mostly gray dolomite. In thin section four fragments were seen to consist of fairly uniform crystals measuring about 0.03 mm. in diameter. No anhydrite noted. Fumes of ammonia, oil and sulphur, on heating in closed tube 4005 4010 277. Dolomite and some shale 4020 4025 278. Dolomite, in part quite coarse-grained, and some shale 4025 4030 279. Dolomite, some with quite coarse crystals, some light gray chert, and some shale 280. Dolomite, some porous. Also some shale 281. Yellow and gray dolomite, some porous. Some shale 282. Dolomite and shale 4030 4035 4035 4040 4040 4045 4050 4055 283. Dolomite, some fragments slightly .porous, shale black, green and gray 4060 4065 284. Yellowish dark gray dolomite, chloritic greenish black shale ; black, dark gray, gray and green shale. Plate 13, A 4070 4075 285. Dark gray dolomite, giving ammonia and sul- phur fumes in closed tube. Not much shale. In thin section the dolomite is seen to consist of crystals about 0.1 mm. in diameter 4075 4080 286. Yellowish gray dolomite, some green and black shale 4080 4085 287. Yellowish gray dolomite and a little black and green shale. In thin section the dolomite is seen to consist of crystals measuring about 0.05 to 0.08 mm. in diameter, and to have small crevices filled with anhydrite. Plate 13, B 4085 4090 288. Dolomite, yellowish dark gray. Fragments of anhydrite noted, also green and black shale. The black shale has minute shreds of vege- tation , 4090 4095 The Deep Boring at Spur 47 Feet From. To. 289. Dark yellowish gray dolomite and some white limestone. (First seen.) The dolomite is seen to consist of crystals about 0.1 mm. in diameter. Some fine textured white anhy- drite noted, and some white chert which has a brown color in transmitted light 4100 4105 290. Mostly yellowish gray dolomite and green and dark shale. A few fragments of white cal- careous f ragmental limestone noted, one with a Fusulina. There is also some white chert. Spicule of sponge noted 4110 4115 291. Mostly dolomite. Some white limestone. Fusu- lina not noted 4120 4125 292. Much of the sample is dolomite and shale. A white limestone has Fusulina. There is con- siderable white flint, apparently occurring with the white limestone 4130 4135 293. Most of the sample is yellowish gray dolomite. Some is greenish and black shale. The rock in which the drill has worked at this depth is a white limestone consisting of organic fragments in a more or less copious matrix of calcite. In this were noted Fusulina, a Nodosaria, and a bryozoan 4140 4145 294. White limestone containing Fusulina. Flint and black and greenish gray shale are also present. A flat Ammodiscus noted 4150 4155 295. The principal ingredient is a white and oolitic limestone. This consists of organic frag- ments, which are grouped in small clusters. Fossils noted in this limestone: Fusulina, Ehombopora (?), crinoid stems, valves of ostracods (?), a foraminifer like a Nodo- saria, with shallow and wide chambers. Flint and dark shale noted 4160 4165 296. White and gray limestone containing Fusulina and some fragments of other fossils. Also some dark shale 4170 4175 297. White, yellow and sr&y limestone, and greenish gray and black shale. The black shale shows small shreds of vegetation. Fusulina, sponge spicules, and pinnules of crinoids noted 4180 4185 298. Grayish and white limestone. Fossils scarce. Fusulina, spicules of sponges, and a Nodo- saria noted. Bluish white chert present 4185 4190 48 Bulletin of the University of Texas Feet From. To. 299. White limestone. Some fragments of a minutely porous yellowish magnesian limestone noted. Fragments of a crinoid stem, of sponge spicules, a Textularia jonesii noted. Bluish chert present 4195 4200 300. Dark gray fragmental limestone with white limestone. Bluish white chert seen, with concentric, botryoidal structure as in agate. Fusulina, sponge spicules and many obscure fossil fragments noted 4205 4210 301. Moderately dark gray limestone. Fusulina, sponge spicules, fragments of bryozoa noted. A thin section of the rock shows it to con- sist of calcite crystals of variable mixed sizes, some aggregations of more even and larger sizes than the average, no doubt rep- resenting places of imbedded fossil frag- ments, traces of which clearly appear in the grouping of crystals in some places. In the mass are imbedded brownish and black shreds and stains of bituminous material ._. 4215 4220 302. Gray and faintly yellowish light limestone. Fusulina frequent, also sponge spicules. Crinoid stem and denticle of annelid,* and a Nodosaria noted 4225 4230 303. Dark gray limestone, containing minute black fragments, 0.10 mm. in leng^th. Sponge spicules and a meandering (tubular?) struc- ture noted 4235 4240 304. Dark gray limestone, with some yellowish white limestone and some bluish flint. Pinnules of crinoids, spicules of sponges, disc-shaped flat bodies, and a Nodosaria noted 4250 4255 305. Dark gray limestone, showing minute black specks, with some white limestone and flint. Spine of brachiopod, many sponge spicules, Textularia jonesii, a flat Ammodiscus of two coils, a fragment of some large shell, a crinoid pinnule, a minute curving tube noted, the latter in the dark limestone 4260 4265 306. Some fragments of ferruginous brown and yel- low limestone, with dark gray and white limestone as in preceding samples. A piece of the brown rock, in thin section, is seen to •Denticles of Annelids are now known as conodonts. The Deep Boring at Spur 49 Feet From. To. be finely fragmental, stained in spots with brown, contains black specks, like the gray- rock in the preceding samples, shows many imbedded obscure organic fragments which are filled with crystalline calcite. Fossils: An ostracod, Nodosaria, a small Ammodis- cus, with two varicose whorls, many sponge spicules, several with rounded ends 4265 4270 307. Blotchy brown and gray limestone, with bluish white flint, all as in preceding sample. Fos- sils: Rhombopora lepidodendroides in flint, Nodosaria, Textularia, Ammodiscus, flat, an ostracod, Serpula (?). Sponge spicules frequent. Fragment of brachiopod shell seen 4275 4280 308. Limestone, bluish white, yellow and dark gray. A fragment of the bluish white limestone in thin section is seen to be an organic frag- mental rock, in which are many fragments of fossils, changed to crystalline calcite. The change has partly affected the matrix also, which is mostly finely granular. Many black specks noted. Fossils: Crinoid pin- nule, Fnsulina cylindrica (?), Nodosellina, sponge spicules, Nodosaria sp., Nodosaria radicula, Trochammina gordialis. Plate 12, C 4285 4290 309. Dark gray limestone effervescing somewhat slowly in acid. Fossils: Crinoid pinnules and stem, sponge spicules, Nodosaria radi- cula, flat Ammodiscus 4295 4300 310. Limestone, some white, some gray and some yellow. Fossils: Spicules of sponges, one clearly a hexactinellid, a Nodosaria, near radicula, and Trochammina gordialis 4305 4310 311. Most of the rock is a white limestone. In thin section one fragment consists of finely granu- lar material in which are irregular traver- sions of more coarsely crystalline portions. Another fragment is almost wholly of finely granular material. In both obscure and more clear outlines of organic fragments occur. Very few black specks were seen, all exceedingly minute. Fossils: Fragments of crinoid stems, and of bryozoa, spicules of sponges, Climacammina antiqua and En- dothyra ammonoides (?) 4315 4320 50 Bulletin of the University of Texas Feet From. To. 312. White, yellow and gray limestone. Some of the white limestone is quite porous. Several Fusulina fragments present. Other fossils few: Trochammina gordialis, hexactinellid sponge spicules, Nodosaria sp., fragments of brachiopod shells and of bryozoa — 4320 4325 313. Mostly white limestone which contains Fusulina. The rock is finely granular and contains im- bedded organic fragments which have not been crystallized. Fossils: Sponge spicules, Nodosaria, a flat Ammodiscus 4330 4335 314. Mostly white limestone, containing Fusulina. Other fossils: Nodosaria, Endothyra, flat Ammodiscus, Nodosaria radicula, sponge spicules, one small circular disc 4340 4345 315. Mostly yellowish white limestone. In thin sec- tion it is seen to contain Fusulina and frag- ments of other fossils imbedded in a granular mass of very finely crystalline calcite, through which are scattered calcite crystals of ten times larger size. In water the sample be- haves as if it were oily. In a closed tube it emits bituminous fumes, and in the oxygen flame the white limestone at first turns black, evidently from carbonaceous material. Fossils: Endothyra, sponge spicules and Nodosaria and Fusulina 4350 4355 316. White limestone like that in the preceding sam- ple. Fossils: Endothyra, Ammodiscus, a very broad and tapering Nodosaria (?), crinoid stem fragments, spicules of sponges 43ft0 4365 317. Cream-yellow organic limestone. Some flint present, bluish white, but brown in trans- mitted light. Fusulina, a large flat Ammo- discus, bryozoan fragment, sponge spicules, denticle of annelid, two species of Nodosaria, Textularia, like jonesi, and other foramini- fera noted 4365 4370 318. Limestone like that in preceding sample. Some dark shale. Fossils: Nodosaria, ostracods, Ammodiscus, spicules of sponges _. 4375 4380 319. White organic limestone, which darkens in closed tube. Fossils are abundant, such as Textularia, Endothyra, Ammodiscus, Tro- The Deep Boring at Spur 51 Feet From. To. chammina gordialis, fragments of bryozoa, spicules of sponges, pinnules of crinoi-ds, Nodosellina priscina (?), and cylindrica, etc. 4385 4390 320. Grayish white and white limestone and black shale. The limestone resembles that in the preceding samples. The shale yields am- monia fumes in closed tube, fumes of sulphur and also faint bituminous fumes. Fossils are frequent, and of same kinds as in the preceding samples 4395 4400 321. Black shale and some gray limestone. The shale gives off strong ammonia fumes when heated in closed tube, and also sulphurous fumes. Pyrite noted. Fossils: Contorted forms of Trochammina are frequent. Am- modiscus, various forms of Nodosaria, sponge spicules, fragments of bryozoa and a crinoid joint noted 4400 4410 322. Shale and some gray limestone. On heating in closed tube, faint bituminous fumes were noted, and fumes of sulphur and ammonia. The limestone darkens on heating. Fusulina present, also some pyrite. Fossils are quite abundant, essentially as in the preceding sample : 4415 4420 323. Rock and fossils as in preceding sample. 4425 4430 324. Black shale giving sulphurous and ammonia fumes on heating in closed tube. Very little limestone. Fossils: Ostracods, Nodosaria, Ammodiscus, Endothjrra, Lagena, sponge spicules, Trochammina gordialis 4435 4440 325. Black shale and some gray limestone. Fossils about as in preceding sample. Some round discs and some branching tubes noted 4445 4450 326. Black shale, yielding oil, sulphur and ammonia fumes when heated in closed tube, and some very white limestone. Fossils about as in preceding sample. Crinoid pinnules noted 4455 4460 327. Black shale, some dark gray shale and some white limestone. In thin section the white limestone is seen to consist of mostly finely granular crystalline calcareous material. In this are some larger crystals of calcite. In the arrangement of the granular mate- rial dim outlines of organic fragments 52 Bulletin of the University of Texas Feet From. To. clearly appear. Fossils : Some circular and oval discs were noted, having irregular cen- tral cavities filled with opaque material. They have a resemblance to Valvulina rudis. Trochammina, Nodosaria, Ammondiscus, a peculiar spine, probably from a crinoid, spicu|l«s of sponges and ostracods noted. Gives fumes of ammonia and sulphur in closed tube 4465 4470 328. Black and dark gray shale and light gray lime- stone. Fossils about the same as in the pre- ceding sample. Valvulina rudis and a young brachiopod, probably Ambocoelia planocon- vexa, noted. Gives fumes of sulphur in closed tube 4475 4480 329. Mostly black shale, with some limestone. Fossils like those in preceding samples and in addi- tion young brachiopods; one showing both beaks (Ambocoelia planoconvexa?) and one like a young chonetes, a young pelecypod showing beaks of both valves, fragments of crinoid stems, and a fluted and tuberculated spine like the spine of an Archeocidaris. Gives fumes of oil and sulphur in closed tube 4480 4485 330. Black and dark gray shale, giving oil and sul- phur and ammonia fumes when heated in a closed tube; white and gray limestone in small quantity. This sample contains some rounded quartz sand grains, mostly from % to % mm. in diameter. Some chert present in this and preceding samples. Fossils as in the preceding two samples 4485 4439 THE FORMATIONS EXPLORED IN THE SPUR BORING The strata explored by this boring constitute three well marked divisions. TJie upper 1250 feet consist of red sands, clays, marls, beds of gypsum, anhydrite and salt, all m different gradations of purity and intermixture. This IS the Permian Red Beds, constituting a part of the Double Mountain formation. The succeeding 2850 feet consist of dolomite, with strata of anhydrite, sandstone and shale. These are probably to be correlated with the Delaware The Deep Boring at Spur 53 formation west of the Pecos and are, no doubt, the equiva- lent of the Wichita and the Albany, the Clear Fork and part of the Double Mountain formation. The lowest 389 feet of the section explored consist of limestone and shale, which are believed to correspond to the upper part of the Cisco formation of central Texas. These beds are here described in the order of the work of thfe drill, from above downward. It will be understood that the drift and pos- sible Triassic present near the surface are neglected on this account. THE RED BEDS Upper Part The uppermost 300 feet of the Red Beds consist of fine silt and clay impregnated with iron oxide, which gives it mostly a deep red color. The greater part of this deposit consists of grains measuring from one to four hundredths of a, millimeter in diameter. The interstitial spaces are filled with ferruginous material of a much finer grade, and this makes the mass relatively impervious to water. These beds contain some interlaminated and concretionary gyp- sum and also concretionary and, possibly, in part stratified, calcareous material. At some depths the calcareous in- gredient is diffused throughout the silt, making it marly. Near beds of gypsum and anhydrite, which this deposit contains, the clays are blotched and streaked with greenish and bluish gray color. At 135 feet below the curb, such a streak of blue gray was reported by the driller. Middle Part From 400 to 900 feet below the surface the Red Beds consist for the most part of fine red sand or sandstone. Some of these strata are only very slightly coarser than the red clays, and nearly all this rock has more or less red silt and ochreous material filling the interstitial spaces among the sand-grains. The coarsest sand was at from 54 Bulletin of the University of Texas 403 to 468 feet, where the rock contained some fine gravel, and at 580 and at 680 feet, where it consisted for the most part of grains measuring from one-fourth to one millimeter in diameter. Calcareous material is present in the sand and appears to be derived from concretions. White streaks or blotches are to be seen on some of the fragments of the sandstone samples, especially near beds of anhydrite. Ap- parently the sand contains thin layers of gypsum, or it is impregnated with gypsum or anhydrite. At some depths it contains a few scales of mica. Two minerals which appear to be common in the coarser strata are crystals of anhydrite and of quartz, few of which measure more than one millimeter in length, when not in clusters. Small crystals of selenite are also quite common. The sand grains are only moderately rounded. Their surface is in many cases slightly etched, and nearly always it has some ad- herent ochreous red matter. The quartz itself is a clear variety. Lower Part The lower 350 feet of the Red Beds consist of a san(^y silt mixed with varying amounts of salt, in which the sand and silt particles are imbedded as in a matrix. Some coarse, almost gravelly sand occurs at from 1174 to 1222 feet below the surface. From determinations of eight samples of the salty rock, its salt content was found to range from 15 to 67 per cent, and to average 36 per cent. The salt has an extensively crystalline structure. It shows reflexions of light from cleavage surfaces, which are continuous across a core six inches in diameter. The greater part of this peculiar salt and sand rock is red, and resembles the finer strata of sandstone. Greenish gray circular spots and streaks occur near beds of anhydrite. Some of the rock is laminated, but it mostly has a marked homogeneous tex- ture. Cores several feet in length were taken from these beds. When exposed to the atmosphere, the salt is slowly volatilized on the surface of the rock, and the contained silt is set free and falls off, causing the rock to disintegrate slowly. The Deep Boring at Spur 55 Salt of the Red Beds There were three beds of pure salt; one ten feet thick, from 570 to 580 feet below the surface; another five feet thick, from 633 to 638 feet; and a third nine feet thick, from 732 to 741 feet. The upper bed consists of white granular salt showing thin red seams about a half millimeter apart, due to the presence of red silt. The lowermost bed is clear, crystalline salt which is transparent, except for imbedded blotches of silt which shows no well-marked stratification. Assuming that the salt-sand in the lower part of the Red Beds measures 290 feet in thickness and contains 36 per cent of salt, the thickness of a stratum representing all the salt shown in the section would be 128 feet for the entire section. Five-sixths of this salt is in the .lower half of the Red Beds. Gypsum and Anhydrite At Spur, as elsewhere, the most characteristic persistent ingredient in the sediments of the Red Beds consists of calcium sulphate minerals, gypsum and anhydrite. Beds of this kind occur from ten to a hundred feet apart through- out the section, in the sandstones, in the clays, and in the salt beds. There are no less than eighteen separate strata in the 1150 feet of all sediments. ' The thickest bed of anhydrite lies from 330 to 403 feet below the surface, meas- uring 73 feet. Another bed measures 30 feet and lies from 540 to 570 feet below the surface; another is 25 feet thick at from 603 to 628 feet, and one of nearly 25 feet below the depth of 1175 feet. Nine beds are five feet thick or less, four are from six to ten feet, and two from eleven to fifteen feet. The combined thickness of all the gypsum and an- hydrite in the section is at least 250 feet. Four-fifths of this thickness lie in the upper half of the Red Beds and the lower part of the heaviest deposits of anhydrite are interbedded with the uppermost, thinnest and purest salt beds. The thickness of strata of mechanical sediments sepa- rating any two beds of gypsum and anhydrite from each 56 Bulletin of the University of Texas other are, in feet, as follows, allowances being made for salt contents: 101 (coarsest sand), 55, 43, 41, 40, 40, 37, 34, 31, 23, 22, 17, 16, 11, 8, 7, 7, 5. The hydrated form of the sulphate occurs in the upper 285 feet of the boring, in the main body of the finer shaly sediments. There are in all seven beds of gypsum, from one to fifteen feet thick. Some of the gypsum is granular and white, and some is coarsely crystalline. It is the latter variety which is called isinglass, by the driller. Red impur- ities are seen in both forms. Between 285 and 298 feet below the surface is a bed consisting mainly of compact anhydrite but containing also some gypsum. Below this depth nearly all sulphate of calcium occurs as anhydrite. Some anhydrite is finely granular and white, but most is very compact and some is sem^i-transparent. At some depths, it is stained red or greenish-gray by silty impuri- ties, and a sample from 992 feet below the surface contained inmbedded grains of quartz. Salt is also present as an impurity, especial/ly in anhydrite containing layers and streaks of sandy or silty admixtures. Anhydrite of this kind was noted at 1005 feet. Calcareous Material Calcareous material is an inconspicuous part in the lower 900 feet of the Red Beds. Fragments of a red granular limestone were noted at 540 feet, and there were calcareous fragments at 603 feet and again at 633 feet. These may have come from layers of limestone, as is be- lieved to have been the case at 540 feet, or the matrial may represent concretions. General Character of the Red Bed Sediments Mechanical sediments make little more than two-thirds of the Red Beds explored in this boring. The rest consists of chemical sediments. The percentages of each kind j>t these sediments in the complex of the formation are about as follows : The Deep Boring at Spur 57 Per cent Gravelly sandstone and sand 5 Sandstone and sand 36 Clay and shale 13 Anhydrite 18 Gypsum 3 Sand and salt, mixed 21 Salt 4 THE DOLOMITE BEDS From 1250 feet below the surface down to 4095 feet the drill was going through what is essentially a formation of dolomites, interrupted by beds of sandstone, shale and an- hydrite, the last of which is to some extent of secondary origin. The thickness of this series is 2845 feet. The per- sistent feature which makes this formation appear some- what as a unit is its dolomitic character. On th6 basis of the nature of its minor elements, the formation may be divided into an upper part, 1730 feet thick, where the pre- vailing minor beds consist of sand and anhydrite, and a lower part, 1115 feet thick, in which the minor beds con- sist of shale. We may refer to these respectively as the sandy and the shaly dolomite beds, although it should be understood that both of these accessory rocks are present as separate beds. THE DOLOMITE Crystalline Texture As to the size of crystals, the dolomite is of fine texture throughout the entire formation. Most of it is very fine in texture. Measurements on the size of the crystals, the grains of the rock, have been made at 15 depths, somewhat arbitrarily selected. It appears that there is a general increase in sizes with depths, as will be evident from the list of the measurements made, and here inserted. 58 Bulletin of the University of Texas Sizes of Dolomite Crystals Depths in feet below surface, Average sizes of crystals in of rock examined thousandths of mm. 10 1600 1800 1800 2214 2392 2624 3046 3835 5 10 5 10 7 8 20 3335 30 3520 5 3715 10 3760 10 3820 20 3855 50 . 3865 20 3865 40 3855 60 3930 40 3985 30 4010 30 4080 100 4090 50 4090 80 4095 100 It will be seen that in the lowermost two hundred feet there is a decided increase in the size of the crystals. The coarsest dolomite is in the lower part of the formation, which rests on limestone. At most depths the crystals are of approximately uniform size. At 3405 feet below the surface the crystals are more or less grouped in clusters, as if agglutinating into new and larger bodies. At 3335 feet such a recrystallization has apparently resulted in uniformly larger crystals in most of the rock, but there remain in the coarser mass some island-like bodies that The Deep Boring at Spur 59 are sharply marked off from the rest of the rock by their finer texture. Nearly all the dolomite is compact. Porous rock is rarely seen, and when found, the porosities are very small. Dolomite with minute open spaces* was noted at 1600, 2476, 3355 and at from 4035 to 4065 feet below the surface. The upper part of the dolomite is known to con- sist, in part, of thick beds. At the depth of 1600 feet a single piece of core was taken out which measured sixteen feet. A core of this length would have been broken in the process of cutting, if there had been any marked horizontal seams of bedding in the rock from which it was taken. Chemical Composition The dolomitic character of the rock is known from the fact that it is throughout comparatively resistant to dilute hydrochloric acid, nearly every sample having been tested in this respect. It is also known from the crystalline tex- ture seen in nearly two hundred thin sections. Though this texture mostly is fine it is seen, in sufficient magnification, to be of the kind which characterizes all dolomites. A sample from the depth of 2264 feet, which to the unaided eye appears very much like limestone, was readily iden- tified as dolomite by its optical properties. An analysis of the same sample made by Mr. S. H. Worrell, Chemist of the Bureau of Economic Geology and Technology, was ac- companied by the note that the sample was a mixture of sulphate of lime and the double carbonate of lime and magnesia. This analysis is as below. Analysis of a Piece of Core from, the Depth of 226Ji, Feet in the Spur Boring, Spur, Dickens County, Texas Lime as sulphate of lime 30.19 . Lime as carbonate of lime 29.34 Magnesia as carbonate of magnesium 22.24 Undetermined 18.24 60 Bulletin of the University of Texas Clastic Texture The process'of dolomitization has left much of the original clastic structure of these sediments in a condition yet to be made out. While the rock consists of minute dolomite crystals, the change has not always obliterated the forms of the particles of which it was to some extent originally com- posed. Some of the original rock was oolitic, and some must have consisted largely of small organic fragments. (Plate 11, B, C, 5 and 7.) Some was perhaps a structure- less calcareous slime, for much of the dolomite exhibits no traces of original clastic structure, other than indistinct lines of bedding planes. Oolitic Dolomite Between the depths of 1250 and 2050 feet only a few samples of rock were received from known depths. It is doubtful if any of the rock samples examined came from the upper 350 feet of this interval. From 1600 feet down to 3120 feet, much of the dolomite is oolitic. Oolite is present in the samples from 1800, 2250 to 2264, 2600 to 2624, 2709 to 2735, 2751 to 2956, 3050 to 3055, and from 3115 to 3120 feet below the surface. Plates lA, 3, 5, 6, 7, 8, 9B, lOA. Original oolitic structure is indicated in several samples by a peculiar grouping of the crystals of the dolomite, where bodies of the common sizes of oolite grains exhibit a finer, and more compact texture, than the rest of the rock in which they lie imbedded. Such texture was noted at from 2271 to 2329 feet, from 2539 to 2548, and from 2900 to 2950 feet below the surface. The oolitic texture has, in some cases, been blurred, as it were, in the process of dolomitization. Plates 1, 2, 3, lOA and 11 A. The oolitic spherules are of variable form, appearing cir- cular, oval, or elongated in a section. Commonly their lesser diameter is two-thirds the length of their greater diameter, but it is in many cases much less than this. Their outline is mostly oval or circular, but it may have any shape, crescentic, triangular, polygonal, always with rounded The Deep Boring at Spur 61 angles. The spherules seldom show any nucleus and not usually concentric structure. Some are merely incrusta- tions enveloping fragments of small shells and of bryozoa. (Plate 7.) Their form is marked by mostly a single ex- ternal layer some 0.05 mm. in thickness. In a few cases the largest spherules were seen to inclose two or three smaller ones, each having their own external layer, inside of the outer layer inclosing them all. Figs. 1, 2, and Plates lA, 3, 5, 6 7, 8, 9B, lOA. The oolitic grains are small in size in all of these rocks, too small to be readily made out without a good hand lens. This appears, from some measurements made, as below: Measurements of Sizes of Oolitic Spherules Depth, in feet Size of longer diam., in Size of shorter diam., in b&low surface lOths of a mm. lOths of a mm. 1800 8.6 6.6 1800 6.9 4.5 2250-2264 11.1 1.7 9.4 5.1 7.7 4.7 6.9 4.7 6.0 3.4 4.3 4.3 3.4 2.6 2.1 1.7 2606-2609 6.5 3.4 5.6 2.1 4.3 3.0 3.8 2.5 3.8 1.7 3.4 3.4 3.4 2.6 3.4 2.1 2.6 1.7 2.1 2.1 2609-2624 6.5 2.1 5.6 3.0 1.7 1.3 62 Bulletin of the University of Texas 2709-2735 5.2 2.6 2.1 2900-2950 6.9 3.0 2.6 2.1 1.7 3050-3055 5.2 1.7 3115-3120 4.3 3.4 2.6 2.1 3.4 3.1 2.1 5.2 1.3 1.7 2.1 1.3 3.4 1.7 2.6 3.4 1.3 2.1 Most of the oolitic rock contains fragments of organic remains mingled with the spherules, some with and some without an oolitic incrustation. Fig. 2. The ratio be- tween the quantities of spherules and matrix is variable within wide limits. Dolomite of Fragmental and Other Texture Some dolomite exhibits a minute concretionary structure, where bodies of fine-grained dolomite are separated from each other by a matrix of relatively coarse grain ; but where the nodular bodies lack the uniformity of size as well as roundness of form, which characterizes oolitic spherules. (Plate lie.) Most of these textures probably had their origin in the clastic structure of the original limestone which may have been an organic sand or silt, composed of imperfectly sorted grains. (Plate 7.) Other specimens seem more likely to have been concretionary, as the fine- grained particles are more generally spherical in form, though lacking the smoothness and the uniformity in size which characterize oolitic spherules. (Fig. 1.) Textures of these several kinds occur at 1600 feet, from 2751 to 2900, 2900 to 2950, 3185 to 3190, 3515 to 3520, 3715 to 3720, 3860 to 3865, 3885 to 3890, and at some other depths. In several The Deep Boring at Spur 63 samples traces of organic fragments, such as gently curving intersections of small shells and the straight outlines appar- ently of spicules of sponges, appear in the grouping of crystals of the rock. (Plate 9A and B.) Such were noted at from 2673 to 2677, 2950 to 2956, 3335 to 3340, 3185 to 3190, 3515 to 3520, 3545 to 3550 feet, and at several other depths. A unique texture was noted in one of the samples coming from between 1250 to 2040 feet below the surface, its exact horizon not being known. At first sight this impure dolomite appears to be a thinly laminated rock. On close examination a vertical section is seen to exhibit thin len- ticular bodies separated from each other by a matrix. The rock is impregnated with bituminous and other opaque impurities. It would appear that such a structure and such residue of impurities might result from the leaching out of much of the calcareous material in an oolite under pressure of the weight of overlying strata. (Plate IB, Fig. 3.) Distribution of Textures All of the textures described occur both intermingled and separately. One-fourth of the samples show no other tex- ture than that of its crystalline make-up and of obscure stratification. Such rock occurs throughout the series as at 2050, 2550, 2725, 3175, 3200, 3225, 3525 feet, and several other depths. (Plates lOB and 12A and B.) Organic f ragmental rock also containing oolitic spherules were noted at 2950 to 2956 feet, 2995 to 2996, 3050 to 3055, 3185 to 3190, 3245 to 3250, 3305 to 3310, 3545 to 3550, 3630 to 3635, and 3715 to 4720 feet below the surface. Figs. 1 and 2, Plates 7, 9B, IIB. In general, oolitic beds are found mostly only in the sandy dolomite from 1250 to 3120 feet, and indications of clastic organic texture are most common in the shaly dolomite from 3120 feet to the base of the formation. 64 Bulletin of the University of Texas Interbedded Sands The main accessory sediments in the dolomitic beds are sand, shale and anhydrite. Small beds of sand are reported by the driller in the upper part of the dolomite as follows : Depths in feet Thickness, in below surface feet. 1. 1538-1546 8 2. 1827-1830 3 3. 1860-1862 2 4. 1877-1884 7 5. 1988-1992 4 6. 2047-2049 2 7. 2392-2395 3 8. 2396-2401 5 9. 2472-2480 8 10. 2541-2551 10 None of these beds exceed ten feet. Only three of them, 1, 6, and 7, are reported unequivocally as consisting of sand only. Numbers 2 and 3 are called sand and flint. In 4 and 5, sand is mentioned as occurring with blue rock. Numbers 6, 7, and 8, so far as known from samples, are beds of red sandy clay or silt. In thei samples from num- bers 9 and 10, no sand appears, except some stray grains of quartz. The samples at all these depths were selected and are not representative for all depths. At two other depths the samples demonstrate the pres- ence of considerable beds of sandstone. The uppermost is from 2069 to 2110 feet, and from 2128 to 2212 feet. Sam- ples taken from these depths consist mostly of ferruginous red clay, which contains some fine sand, the grains meas- uring mostly from 0.1 to 0.2 mm. in diameter. Some mica is also present here. The other sand rocks appear in the samples at from 2644 to 2660, from 2664 to 2673, and from 2735 to 2751 feet, below the surface. These sandy beds also contain much red clay, and the sand is of fine texture. In The Deep Boring at Spur 65 the lower group of red sandy shale, from 2664 to 2751 feet, there is also some very dark gray, and almost black shale. The two and a half hundred feet of sand reported by the driller below 2751 feet is probably partly dolomite, contain- ing minor beds of sand. The dolomite is largely oolitic at this depth. It is significant of the relationship of these sediments to the Red Beds above that their sandy clay beds are both ferruginous and of nearly the same mechanical composition as in the Red Beds. Below 2800 feet these red clayey sands do not occur. In the Red Beds the sands and clays, and even some gypsum and anhydrite, are mostly of a deep red color. The red color of the ferruginous sands between 2000 and 2700 feet decreases in brightness downward and be- comes brownish. It appears that in some of the red or brown rocks reported in shale and dolomite below the depth of 3000 feet the coloring has not affected the entire rock but belongs to separate layers, or the color is present in spots or blotches; for some fragments show blue as well as brown color. The combined thickness of beds of red clayey sands in the dolomite formation is estimated not to exceed 300 feet. Interbedded Shale The only shaly material reported by the driller from the oolitic upper part of the dolomitic beds evidently was pres- ent as thin seams in the main rock. At from 1397 to 1403 feet, there were soft blue streaks in dolomite. Soft streaks were Encountered in the same kind of rock at from 1425 to 1433 feet, and from 1454 to 1461 feet. Blue sandy and shaly rock was noted at from 1546 to 1551 feet. In the lower division of the dolomite shale is noted at two depths, from 3060 to 3075 feet and from 3667 to 3669 feet. The presence of shale at the last two depths is also shown by the speed attained in drilling, which increased much for the space of nearly a hundred feet below the depth of 3060 feet, and increased slightly for a short distance below 3660 feet. Examining the cuttings, much more shale is found than would be expected from the driller's record. But few 66 Bulletin of the University of Texas samples are without shale, and many consist of more shale than dolomite. To some considerable extent this is no doubt due to caving, material from soft shaly strata falling from the walls of the hole to be ground up by the bit and later to appear in the returns. But it is doubtful that all of the shale present can be accounted for in this way. This appears from the recorded rate of drilling. Below 3067 feet this rate rose from 6 and 7 feet per day, the usual rate in limestone, to 18, 20, 20, 16, 17, 14, and 13 feet for the succeeding seven days of drilling. After this the rate continued at an average of about ten feet per day for the next thousand feet. Even in this more steady rate there were considerable variations ; from 6 and 7 feet some days, to twice these figures. It is believed that these minor differences were due mainly to the presence in the dolomite of layers of shale that, for the most part, were too thin to attract particular attenion. Equally strong evidence of such conditions the writer finds in the nature of the shale itself present in the samples. The heaviest shale reported by Mr. Minihan at from 3060 to 3075 feet is a dark gray and dark green-gray shale, that lacks other characteristics. Such shale occurs all the way down. Black shale is not seen until the depth of 3235 feet, and below 3700 feet black shale is more frequent than above this depth. Shale of light gray color is more frequent from 3350 to 3500 feet than either above or below this horizon. Bluish-gray shale is more in evidence at from 3200 to 3325 and from 3450 to 3560 feet, than either above or below these depths. Shale containing shreds of imbedded vegetation in the form of "natural charcoal" was noted four times be- tween 3555 and 3620 feet, and once near 4090 feet, but at no other depths. Thinly laminated shale is seen in three sam- ples between 3535 and 3620 feet, but is not present else- where. Pyrite occurs in shale of a sample taken at from 3200 to 3205 feet, and was noted also in anhydrite in a sample taken ten feet below this. Mica was noted in two samples taken from between 3630 and 3640 feet. ! Both of these minerals are no doubt present in much of the shale, but not in particles large enough to be conspicuous. ' All of these circumstances are believed to warrant the conclusion The Deep Boring at Spur 67 that much of the shale present with the dolomite throughout the section belongs to the rock with which it comes. If all this shale were the result of caving from one or two levels, it would be of a more uniform character. In the absence of sufficient data for estimating how much of the shale in the samples has been introduced by caving, it is not believed that an estimate on the total contents of shale would be warranted, farther than that a combined thickness of 200 feet of shale appears to be a safe minimum. Anhydrite Through the whole dolomite formation, anhydrite is a considerable ingredient in all samples. As this rock does not cave, it is believed that the quantity of it present in the samples correctly represents its quantity in the section, relatively to the dolomite and the sandstone. The scarcity of samples from 1250 to 2040 feet prevents any close estimate as to what part of the rock between these two depths was anhydrite. There may have been a large proportion of anhydrite. The sample from 1235 to 1250 feet is mainly anhydrite.- At 1950 feet the core con- sisted of an almost pure and translucent compact anhy- drite, of bluish-gray color. Most of the rock in this part of the boring is reported by Mr. Minihan as "rock," and not as limestone. This suggests that it was a rock differ- ent from limestone. Anhydrite is reported in similar terms at from 2064 to 2068 feet. At a few other depths it is undoubtedly reported as limestone. As nine of the ten- samples selected to represent the strata from 1250 to 2040 feet consist of dolomite, and only one is anhydrite, the presumption is, nevertheless, that there was consider- ably more dolomite than anhydrite. From 2040 down to 4095 feet at least twenty-five per cent of the formation is anhydrite, as near as can be judged from the data at hand. It is also clear that there is much more anhydrite in the upper oolitic and sandy dolomite than in the lower and shaly dolomite. Two methods have been used to estimate, from the con- tents of the samples, the quantity of anhydrite in each hundred feet of the section, from 2000 to 4095 feet below 68 Bulletin of the University of Texas the surface. One of these methods consisted in counting a convenient number of fragments of each kind of rock in each sample, and thus roughly determining the percentage of anhydrite. Some of the samples consist almost entirely of anhydrite, as from 2064 to 2068 feet, and from 3105 to 3110 feet below the surface. From 2200 to 2600 feet several samples consist largely of anhydrite, and there are such samples from 2700 to 3000 feet. Belov7 3110 feet the anhydrite content obtained by examining the cutting varies from 15 to 4 per cent, decreasing gradually downvs^ard. The percentage for all the samples between 2000 and 3000 feet is 25, and for the samples between 3000 and 4095 feet it is a little less than 10, making the average for the whole formation about 17 per cent. Secondary Anhydrite But these percentages do not represent the total contents of anhydrite in the formation ; for in making the estimates by counting separate fragments, no account could be taken of the anhydrite occurring as microscopic crystals in the dolomite. A separate estimate was therefore made on the anhydrite included in dolomite, by roughly measuring the areas of anhydrite and dolomite in 186 thin sections pre- pared from cuttings of the dolomite. These cuttings were taken from 60 different depths, selected so as to represent each hundred feet in the section as nearly equally as prac- ticable. Only 18 per cent of the thin sections were without anhydrite, and more than half of these were from the lowest 500 feet of the dolomite. The remaining 82 per cent of the sections contained from 1 to 60 per cent of anhydrite, apparently replacing part of the original sediment. Sepa- rate estimates were made for each 100 feet of the section, and account was made of the fact that each of these esti- mates represents only the anhydrite present in the per- centages counted as dolomite in the previous estimates. These estimates show an additional 10 per cent for the whole section, 11 per cent for the upper oolitic and sandy dolomitic beds, and 8 per cent for the lower shaly dolo- mitic beds. The Deep Boring at Spur 69 It is probable that these two estimates slightly overlap, that a few of the thin sections contain so much anhydrite that they might have been counted as anhydrite in making the first estimate. There is also an uncertainty as to the amount of shale present due to caving, and this prevents making a correction for the quantity of shale in each sample. The presence of caving shale would not affect the estimates, but the presence of shale belonging to the terranes would make the estimates too high. Taking this all into due consideration, it seems safe to conclude that the total anhydrite content is somewhere near 25 per cent for the whole formation; 35 per cent for the upper sandy and dolomitic beds from 2000 to 3000 feet below the surface; and 15 per cent for the lower shaly dolomitic beds between 3000 and 4095 feet below the surface. (See Plate 13.) The following table of the two series of estimates for each hundred feet of rock will show the stratigraphic dis- tribution of the anhydrite in greater detail : TABLE Showing estimates of contents of anhydrite in each hundred feet from 2000 to 4096 feet below the curb of the Spur boring Estimates based on ratios Estimates based on ratios of fragments of of anhydrite and Part of anhydrite to fragments dolomite in microscopic Estimated section in of other rocks in samples sections total per f apt hplnnr cent of anhydrite surface No. of 1 Per cent No of Per cent samples of sections of examined anhydrite examined anhydrite 2000-2099 4 19 3 6 25 2100-2199 2 12 1 26 38 2200-2299 9 12 13 6 18 2300-2399 6 35 S 13 ts 2400-2499 3 60 1 Trace 60 2500-2599 2 50 5 4 64 2600-2699 11 10 30 18 28 2700-2799 3 40 12 10 50 2800-2899 30 12 42 2900-2999 6 20 17 18 38 3000-3099 14 15 8 14 29 3100-3199 19 IB 15 13 28 3200-3299 19 15 11 2 17 3300-3399 19 12 8 2 20 3400-3499 20 11 9 12 23 3B00-3599 18 8 6 3 11 3600-3699 20 7 13 20 27 3700-3799 9 7 5 14 '21 3800-3899 9 7 10 8 15 3900-3999 8 4 9 1 5 4000-4095 14 4 7 2 B 70 Bulletin of the University of Texas Origin of the Anhydrite That a part of the anhydrite in the sandy dolomite rep- resents original beds of anhydrite cannot be doubted. The samples from 2331 to 2336, 2454 to 2460, 2476 to 2539, 2539 to 2606, contain little else than anhydrite. That much anhydrite in the whole section, and practically all below the depth of 3000 feet, is a secondary constituent, is equally clear. It occurs in crystalline form in small cavities in the dolomite throughout the formation. In some sections it is seen to replace parts of spherules in the oolites. (See Fig. 1 and Plate 2A.) Elsewhere it forms the matrix in which the oolitic spherules are imbedded. (Plate 8B.) In still other cases it forms the matrix and also fills the interior of spherules wholly or partly, and the crust of the spherule is alone composed of dolomite. Still other sections show a matrix of dolomite in which the emptied forms of the spherules have been filled with anhydrite. (Plate 8A.) In every case the introduced mineral shows relations to the oolitic structure of the rock, which it cannot have had originally. It is secondary in its present distribution. In one or two sections it appears to be collected into minute concretions. (Compare Plate lOA.) From near 2250 feet below the surface a piece of core was taken, which contained a concretion of anhydrite three inches in diameter and several concretions of smaller size. (See Plate 4.) The writer is inclined to the belief that much of the anhydrite has been formed in connection with the dolomitizatipn of the limestone, as the result of a reaction between magnesium sulphate in circulating solutions and the calcium carbonate of the original sediment. This would explain the gjeneral diffusion of the anhydrite throughout the doloipite. i Nat- ural conditions have elsewhere caused anhydrite to be de- posited in separate beds. Here we find 1000 feei ancj more, of dolomite, which contain from 10 to 30 per cent of anhy- drite in intimate mixture, almost everywhere. Another reason for believing conditions were different liere Is to be found in the fact that anhydrite ceases to appear in the The Deep Boring at Spur 71 cuttings at the depth where the drill passed from dolomite into limestone. OTHER MINERALS Quart;^ Quartz was noted in this rock in two forms. It occurs as chalcedonic quartz, mostly associated with concretions of anhydrite, which in some cases have an outer discontinuous and irregular layer of such quartz. Concretions of this kind were noted in cores coming from 2244 and from 2250 feet below the surface. (See Plate 4.) In the upper sample the concretions were from one-half to one inch in diameter, and in the lower from a half to nearly four inches. The largest of these concretions had such quartz also in irregular accumulations in its interior. Some very small concretions of quartz were noted in a piece of dolomite be- lieved to have come from a depth of 1600 feet. A siliceous dolomite caused very slow drilling at the depth of 2214 to 2219 feet. In this rock the siliceous material is, at least in some of the rock, diffused in the dolomite, making this cherty. A gray chert of uniform texture made part of a core taken at from 2241 to 2271 feet below the surface. Clusters of straight microscopic bodies of quartz were noted in a sample taken at 2260 feet and again in a sample at from 2271 to 2329 feet. Drilling was very slow near these depths, and the chert must have been present in considerable quantity. But from this depth down to past 3900 feet, no more chert, flint or other secondary quartz appear in' the cuttings. Some chert occurs at from 3965 to 3970 feet and at from 4030 to 4035 feet. At the latter depth it is light gray in color. Calcite Calcite is scarce throughout. Calcareous particles, ef- fervescing promptly in acid, are usually lighter in color than the rock with which they come. They probably repre- 72 Bulletin of the University of Texas sent veins or concretionary segregated bodies of other forms. They were most frequently noted at 3180, 3230, 3350, 3365, 3420, 3430, 3540, 3590, and 3640 feet below the surface. Pyrite Much pyrite was reported by Mr. Minihan at from 2241 to 2271 feet, where it also appeared in the samples. Other- wise pyrite is rarely seen in this rock. It occurs as micro- scopic cubes in anhydrite at from 3205 to 3215 feet, aiid it was present in shale immediately above this depth. It was also noted at from 3350 to 3355 feet, from 3755 to 3760, and from 3935 to 3940 feet. There is no doubt of its presence in small quantities at many other depths, especially in,' dark shale and in dark dolomite that emit sulphurous fumes on heating. ' Gypsum and Salt Some small crystals of gypsum were noted in the sample from 2956 to 2980 feet, and the impure dolomite occurring between 2042 and 2047 feet contains some salt. Bitumen and Am,monia In many of the thin sections of dolomite, black, brownish, or yellowish streaks were noted, that evidently were not iron or manganese oxide. (Plate 12B.) On heating parts of some of these samples, and several others, in a closed tube, it was found that nearly all such rock yielded fijmes of bituminous materials. In several cases, perceptible films or even minute drops of oil were obtained. Many samples also gave fumes of ammonia. Distillates of bjtuminous substances appear to be most frequent, and also (most pro- nounced, at depths from 3000 to 3800 feet, while ammonia fumes appear to be most frequent from 3800 feet to the bottom of the dolomite. The two often occur together] The bituminous material is most common in dolomite, having been noted in shale in only one instance. Out of iss samples The Deep Boring at Spur 73 of rock heated in a closed tube, 27 gave bituminous fumes or both fumes and visible oil. Estimates based on the ascertained weight of minute quantities of oil obtained from a fourth of a grain of limestone indicated that the bitumi- nous contents range from quantities too small to estimate, to one-tenth of a per cent of the weight of the rock. Below is a list of the tests made, showing the results in each case. As no attempt was made to select the samples tested, they may be regarded as fairly representing the part of the formation from which they were taken, the mark * denoting the occurrence. Depths. Bituminous fumes noted in closed tube. Visible oil noted in closed tube. Fumes of ammonia noted in closed tube. 1250-2042- - * * * * * 2250 - 2241-2271 - ■" 2250-2264 .. 2260 - * 2392-2394 2685-26G8...- * 269 8-2709 « * * • "- 2987-3002 3165-3170 * 3185-3190 3205-3210 3285-3290.. * * * * * * * * * * • * * ' 3355-3360 3470-3475.... — 3605 3610 « * 3680-3685 — 3690-3695 369 5-3 700 ,. * 3700-3705 ' 3710-3715.- 3735-3740.. _ * 3755-3760 , 3765-3770 3775-3780 * * 3795-3800 3810-3815 3830-3840 ._ * * * 3850-3855 3915-3920 3930-3935 * 3945-3950 3985-3990 * 4005-4010 * 4075-4080 74 Bulletin of the University of Texas THE CISCO FORMATION Fragments of limestone first began to appear with the cuttings from 4100 to 4105 feet, and fragments of Fusuiina appeared in the next sample below this, from 4110 to 4115 feet. After its first appearance, the limestone increased in quantity steadily in the returns for the next forty feet. Below 4150 feet the samples contained but little dolomite, consisting mostly of limestone and shale, down to the bottom of the well. It is believed that the strata penetrated by the lowermost 394 feet of this boring are to be correlated with the upper part of the Cisco formation in the central part of the State. They consist of limestone and shale. Limestone is the chief rock from 4100 to 4400 feet, while the lowermost 89 feet are mostly shale. Limestone The limestone in the formation presents several varieties. In nearly all the sections examined, organic fragments are present as a notable ingredient. (Plate 12C.) One thin section is a granular crystalline limestone, in which the crystals are of two somewhat uniform sizes. The matrix consists of crystals from 0.01 to 0.02 mm. in diameter, and in this lie scattered bodies of clear calcite from 0.05 to 0.1 mm. in diameter. Most of the sections consist of a matrix composed of particles of calcite less than 0.01 mm. in diameter, and in this lie organic fragments and larger bodies of calcite up to the size of a half millimeter. Several instances were noted where the larger crystalline bodies of calcite were fillings in cavities having the outlines of organic fragments, such as pieces of shells or of stems of crinoids or spines of brachiopods. (Plate 12C.) In other instances, organic fragments were seen to have their internal structure preserved. At the depth of 4160 to 4165 feet, some of the limestone is oolitic. It is filled with oolitic spherules im- bedded in a matrix having a texture like that of the other limestone, showing large variations in the size of the calcite The Deep Boring at Spur 75 grains. Some oolitic spherules occur together with a multi- tude of organic fragments in the limestone from 4315 to 4320 feet. The sizes of the spherules in both these cases range mostly from 0.5 to 1.5 mm. in diameter. At from 4265 to 4270 feet occurs a brown limestone, which is rusty- colored ; however, only in spots. There is evidence here of alteration of the rock by the occurrence of calcite in cavities once filled by imbedded organic fragments. In all of this limestone it is believed there are, here and there, some seams of shale. Below the depth of 4400 feet, limestone and shale appear to alternate to the bottom of the boring, the shale predominating. Much of the limestone in the lower 300 feet of the boring darkens when first heated in a flame, indicating the presence of organic material, as it again turns to a lighter color when ignited for a longer time. Flint, or chert, is present in this limestone at several depths. White flint was noted at from 4130 to 4135 feet and from 4150 to 4155 feet. Bluish-white chert occurs at from 4205 to 4210, from 4250 to 4255, from 4260 to 4265, from 4275 to 4280, and from 4365 to 4370 feet. Shale The shale in the lowermost hundred feet is mostly very dark or black, and at some depths it contains pyrite, as at from 4400 to 4420 feet. Of eleven samples from this forma- tion, three yielded oil and three more yielded perceptible fumes of bituminous distillates, when heated in a closed tube. Seven yielded fumes of ammonia. Most of these tests were made on samples of shale, but bituminous sub- stance occurs also in some of the limestone. Shale yielding oil occurred at the depths from 4455 to 4460, 4480 to 4485, and from 4485 to 4489 feet. A light showing of gas was reported by the driller at near 4435 feet. NOTES ON FOSSILS For the purpose of making the record of this deep boring as complete as possible, all samples were examined for fossils. Only a few macroscopic fossils were seen. These were in a core taken between the depths of 2244 to 2264 76 Bulletin of the University of Texas feet. All other fossils were minute forms, found either in thin sections of dolomite and limestone or recovered by washing the triturated material in samples of cuttings taken by the drillers. Drawings have been made of a little more than a hundred individual specimens. These comprise sev- eral ostracods, some jaws of annelids, one or two brachiopods, one gastropod, several bryozoa, some sponge spicules, and a considerable number of foraminifera. Though foramini- f era are, as a rule, of little importance for the identification of geological horizons, they are the principal material at hand in this case. It is thought that with a thorough study of the lithology and of the microscopic fossils in the Car- boniferous and the Permian section in the State it will be possible eventually to definitely correlate all the parts of the section of this boring with the existing formations elsewhere. Fossils in the Cisco The principal fossil-bearing horizon is the Cisco, the low- ermost 389 feet of the exploration. Fossils occur in the limestone as well as in the shale. Fusulina, Rhombopora, other bryozoa, and crinoid stems were noted most frequently in the limestone. Chitinous and other agglutinate foram- inifera, jaws of annelids, and spicules of sponges were most frequent in the shales. A majority of these fossils are known from the Carboniferous in Europe and America, a few are known from the Permian, and some have probably not been reported from any other locality. A brief descrip- tive list, giving references to the respective drawings, is as below. LIST OF FOSSILS FROM THE CISCO FORMATION Several specimens of a shell resembling Climacammina antiqua Brady were noted. These were not very well preserved, and were more or less fragmentary. Two came from the sample taken between 4415 and 4420 feet, one from 4475 to 4480 feet, and one from 4485 to 4489 feet. The texture of the test could not be seen, but the labyrin- thic intergrowths of the test into the chambers were evident, the The Deep Boring at Spur 77 latter being filled with a perfectly opaque mineral. This form has been observed throughout the entire Carboniferous of England and Scotland, and it has been doubtfully noted in the Fusulina limestones of Russia. Figs. 4: a, c. Figure 4. a, c, Climacammina antiqua Brady, from 4315-4320 feet below surface; b, unknown form, 4415-4420 and 4475-4480 feet; d, unknown form, 4485-4489 feet; e, unknown form, 4445-4450 and 4425-4430 feet. X 40. Some very delicate, non-septate, and branching tubes were noted in the lowermost fifty feet of the well. Figure 4: d, e. Forms which more or less resemble Nodosaria radicula, Nodosellina cylindrica, and Dentalina are common in the lowest two hundred feet of the Spur well. Some have the walls of the segments slightly bulging, in others the segments form tubes of uniform diameter. The segments are of variable length and diameter in most individuals. Some tests are perfectly straight, others show slight irregular bends. A protruding aperture is sometimes shown on the last segment. These forms are known from the Carboniferous and up. Figure 5 : a — m. \y. o ^ 0, / U ■w. Figure 5. Unknown forms: a, 4455-4460 feet below surface; b, 4367-4370 feet, 4315-4320 feet; c, 4455-4460 feet; d, 4425-4430; e, 4445-4450 feet; f, 4455-4460 feet; g, 4385-4390 feet, 4405^410 feet; h, 4405-4410 feet; i, 4285-4290, 4425-4430 feet; j, 4285-4290, 4405- 4410 feet; k, 4485-4489 feet; 1, 4445-4450 feet. X 40. 78 Bulletin of the University of Texas In the lowermost hundred feet were some minute fusiform frag- ments of fossils which have a resemblance in outline to Saccam- mina and Lagena, also known from the Carboniferous. Figure 6: a— e. Figure 6. a, Lagena (?), 4445-4450 feet below surface; b, Sac- cammina (?), 4385-4390, 4405-4410, 4415-4420, 4435^440, 4465-4470, 4480-4485, 4485-4489 feet; c, Lagena (?), 4485-4489 feet; d, Lagena (?), 4415-4420 feet. X 40. There are a number of delicate tubular organisms, of apparently homogeneous texture, which resemble in form Trochammina gor- dialis and incerta, figured by Brady. The shell is sometimes of ferru- ginous color, but also colorless. All are more or less chitinous. . Most of the forms are small. Figure 7: a — h. fno^'^T^ '^' Tro'=^ammina incerta d'Orbigny, a, 4305-4310, 4475-4480 feet below surface; b, 4385-4390 feet; Trochammina eordiali^i Tones f^.^.P.ri^'^' "' 4395-4400, 4405-4410 'feet; d, ^25-4430 4445^450 4455-4460, 4465^4470, 4475-4480, 4485-4490 • e 4405-4410 4425144^0 4445-4450 feet; f, 4395-4400, 440E.-4410, 4415-1420 4425-443oieet' g, 4480-4485 feet; h, 4415-4420, 4425-4430, feet X 40 ' Flat spirally-coiled tubes of chitinous material were noted at from 4150 feet to the bottom of the well. These resemble the genus Ammodiscus. In the diameter of the tube they differ considerably, and also m the number of coils. In some the inner whorls are of about the same diameter as the outer, and at the center is usually seen a chamber, which often has a wider diameter than the tube. Where the inner whorls are very small no such chamber is seen The Deep Boring at Spur 79 The discs range from 0.1 to 0.3 mm. in diameter. Figure 8: a, b, c. Several tests were noted which had an exterior resemblance to Valvulina bulloides as figured by Brady. These consisted of one :arge segment having one or several smaller segments attached on one side. It is quite probable that they are irregular forms of Endothyra. Figure 8: d, e, f. Figure 8. Ammodiscus sp., a, 3755, 3775, 3795, 3820, 4150, 4260, 4275, 4300, 4330, 4340, 4360, 4365, 4375, 4400, 4420, 4430, 4450, 4460 feet below surface; b, 4275-4280, 4330-4335, 4340-4345, 4360-4365, 4365-4370, 4375-4380, 4385-4390 feet; Valvulina bulloides Brady; d, 4395-4400 feet; f, 4415-4420, 4405-4410 feet; g, Endothyra bowmani Phillips, 4340-4345. 4350-4355, 4360-4365, 4365-4370, 4375-4380, 4385- 4390, 4405-4410, 4415-4420, 4425-4430, 4445-4450 feet; h, 4380-4385, 4385-4390, 4480-4485 feet. X 40. Some more or less disc-shaped or cone-shaped tests with an uneven exterior surface showed dim oblique lines indicating boundaries of segments arranged somewhat as in Valvulina rudis Brady. The specimens seen had the interior more or less filled with an opaque mineral. This species has been noted by Brady from the fusulina- bearing Carboniferous in Iowa. Figure 9: a, b, c. Figure 9. Valvulina rudis Brady, a, 4465-4470 feet below surface; b, 4475-4480 feet; c, 4475-4480 feet; unknown, d, e, 4385-4390, 4395r' 4400 feet. X 40. Discs with a central circular area are not rare, varying from 1 to 3 mm. in diameter. One had a cross in the central circle like the out- line of the last chambers in Valvulina palaeotrochus. Some of these discs are probably detached segments of cylindric forms of various foraminifera. Figure 10: e, f. 80 Bulletin of the University of Texas Figure 10. Endothyra sp., a, 4445-4450, 4455-4460 feet below sur- face; b, 4315-4320, 4425-4430 feet; Textularia (?), c, 4265-4270 feet; Textularia (?), d, 4415-4420, 4445-4450, 4455-4460, 4475-4480 feet; unknown, e, 4250-4255, 4275-4280, 4340-4345, 4385-4390 feet; f, 4465-4470 feet; g, Fusulina cylindrica, occurs frequently from 4115 to 4350 feet (cross section, X 50). X 40. A few segmented structures with a rough exterior and a thick and irregular wall were noted at the depths 4385 to 4400 feet below the surface. The interior is filled with an opaque mineral and the interruptions in this filling mark the segments more than the external form. The organisms were evidently free. Stacheia? Figure 9: d, e. Some forms quite like Nodosaria are laterally unsymmetrical, and have one side straight and the other convex. These may be halves of Textularia Jonesi Brady, which is known from the Kupfer- schiefer in Germany and in the Upper Magnesian limestone in Eng- land, both Permian. These were noted in the lowermost 115 feet of the well. Figure 11: e, f, g, h. One of the most common foraminifers in the lowest 400 feet penetrated by the Spur well is a flat arrowhead-shaped test, from less than % to more than % mm. in length. It consists of a primordial spherical chamber, on one side of which adhere a series of later chambers of successively larger size. The increase in size of successive chambers is variable, decreasing in the two or three last ones, the last chamber sometimes being smaller than the one next preceding. Interiorly, the chambers are smooth. The septal lines are concave toward the primordial chamber. In the progressive widening of successive chambers there is much variation. In some specimens the increase in size is small, while in others it causes the lateral outlines to diverge fifty degrees. The aperture was not seen but a dim median structure was noted in one instance. The fact that only one side is filled by an opaque mineral in some chambers The Deep Boring at Spur 81 in another specimen indicates the presence of some median structure preventing the completion of the filling. The depth of the chambers varies from one-half to one-fifth of their width. Forms like these were noted in most samples below 4195 feet. This form is more common than any other f oraminif er noted. Figure 11 : a, a, a", ,b, c, d, d'. The test resembles Geinitzia post-carbonica Erich Spandel in some respects. A well-preserved fragment, very gently tapering, broken at both ends, with the form of segments figured by Geinitz from a drawing by von Reuss of Textularia multilocularis from the Lower Zeehstein, was noted in the sample from 4480 to 4485 feet. Figure 11: i. Figure 11. Nodosaria (?) a, 4225-4280, 4295-4300, 4305-4310, 4330-4385, 4360-4365, 4375-4380, 4385-4390, 4405-4410, 4415-4420, 4425-4430, 444&-4450, 4480-4485 feet; b, 4375^380, 4385-4390, 4405- 4410 (several), 4415-4420 (several), 4465-4470, 4480-4485, 4485-4489 feet; c, 4360-4365, 4375-4380, 4405-4410, 4435-4440, 4445-4450 feet; d, 4195-4200; 4365-4370, 4385-4390, 4455-4460 feet; Textularia Jonesi Brady (?) e, 4275-4280, 4385-4390, 4395-4400, 4425^-4430, 4445-4450 feet; f, 4480-4485 feet; g, 4375-4380, 4445-4450 feet; h, 4455-4460 feet. X 40. A single individual test noted at 4270 feet below the surface, con- sisted of segments biserially arranged as in Bigenerina or Textularia. Figure 10: c. In the lowest 100 feet of the well a test was noted having segments biserially arranged increasing rapidly in size and overlapping each other far. The external surface was smooth and the septal lines distinctly marked. It had the appearance of a hyaline test. Tex- tularia, sp.? Figure 10: d. Some tests, which no doubt are an Endothyra, have the segments more numerous than they are in Endothyra jonesi, and the sutures extend obliquely inward, from the periphery. They may, perhaps, be referred to E. globulus Brady. Figure 10 : a, b. Tests of the form of Endothyra bowmani were noted from the depth of 4340 to 4450 feet below the surface. This is known from both the Lower and the Upper Carboniferous. Figure 8: g, h. 82 Bulletin of the University of Texas Fusulina was noted in fourteen samples as follows: 4115, 4135, 4155, 4165, 4175, 4185, 4190, 4210, 4220, 4230, 4325, 4350. In the central part of Texas Fusulina has not been reported from higher up than the Cisco. Figure 10: g. Spicules of sponges are common. Dimeres, tetrameres, pentameres and hexameres were noted. The dimeres occurred in two forms, one with blunt and one with sharp points. The tubular axial cavity in the spicules was noted in several cases. These fossils evidently rep- resent the Dictyospongidae. Figure 12: a — h. Figure 12. Pentamere sponge spicules, a, 4415-4420 feet below surface; b, 4320-4325 feet; tetramere, c, 4275-4280 feet; hexamere (?), d, 4305-4310 feet; tetramere, e, 4425-4430 feet; dimeres, f, 4320- 4325 feet; g, 4250-4255 feet; h, 4195-4200, 4215-4220, 422&-4230, 4275-4280, 4285-4290, 4330-4335, 4365-4370, 4385-4390, 4415-4420, 4445-4450, 4465-4460, 4475-4480 feet. X 40. Pinnules and spines of crinoids and especially joints of the stems of crinoids are often present in the Cisco. The pinnules are grooved on one side. An unusual form is shown in Figure 13: f. A fluted and tuberculated spine of an echinoid was noted at 4485 feet. Archeocidaris? Rhombopora lepidodenroides was noted at 4165 and 4275 feet, and between these points, but seldom below. Other bryozoa were scarce but not absent. One is represented in Figure 13: d, another in Figure 13: e. Figure 13. Jaws of annelids,* a, 4446-4450 feet below surface; b, 4385-4390 feet; c, 4225-^230, 4295-4300; 4365-4370 feet; d, uniden- tified bryozoan, 4425-4430 feet; e, ditto, seen in a thin section in limestone, in cross section, 4140-4145 feet; f, pinnule of crinoid C) 4465-4470 feet. X 40. ' •These are now known as conodonts. The Deep Boring at Spur 83 Ambocoelia planoconvexa is believed to have been represented in the two next to the deepest samples. Two very young specimens of a brachiopod of this type were noted. One of these is shown in Figure 14: a, in imperfect rough' outline. A valve of a shell of unknown affinities was seen in the next to the last sample in the well. It is shown in Figure 14: i. Broken parts of chitinous jaws resembling forms ascribed to annelids were noted in a few samples. Three of these are probably referable to one and the same species, differing only slightly in Figure 14. Ambocoelia planoconvexa (?), a, 4475-4480, 4480- 4485 feet below surface; b, apex of gastropod, 4395-4400 feet. Sim- ilar apexes noted at 4275-4280, 4415-4420, 4465-4470, 4480-4485, 4470-4475, 4485-4489 feet; c, ostracods, 4275-4280, 4445-4450 feet; d, 4385-4390 feet; e, 4435-4440 feet; f, 4415-4420, 4435-4440 feet; g, 4465-4470, 4475-4480 feet; h, 4265-4270, 4375-4380, 4425-4430, 4465- 4470, 4475-4480 feet; i, affinity obscure, 4480-4485 feet; j, fish scale (?), 4365-4370 feet. X 20. form. All were fragments. Figure 13: a, b, c. Apexes of gastropods were noted in eight samples, one at 4280 feet, and the rest all below 4400 feet. One is shown in Figure 14: b. Ostracods occur in the samples from 4265 to 4480 feet below the surface. All the individuals being small and probably young and seen but from one side, their identification is uncertain and could be made only from the general outlines of the specimens seen. Aparchites humerosus, Bairdia beedei, and Jonesina boUiaformis ap- pear to be represented. The forms named are known in the Permo- Carboniferous of Kansas and in the Carboniferous and Permian of Texas. Figure 14: c — h. An organic fragment which bears some resemblance to a fish scale was seen at the depth of 4370 feet. It was of material having a yellowish color. Figure 14: j. 84 Bulletin of the University of Texas Fossils in the Shalv Dolomite Beds A few fossils were noted at scattered intervals in the samples coming from the shaly dolomite beds. Some seem to come from the shale, which is interbedded in the dolo- mite. Ammodiscus, a flat spiral form, frequently noted in the Cisco, was found at from 3755 to 3760, 3775 to 3780, 3795 to 3800, and from 3900 to 3905 feet. (Fig. 15 : a.) Sponge spicules were also noted in several thin sections of the dolomite. Undoubted specimens of sponge spicules were noted below 3800 feet in several samples, evidently having come from shale. In a fragment of limestone from 3185 to 3190 feet there was a section of some bivalve, much frac- tured. (Fig. 15 :f.) Fossils from the Sandy Dolomite Beds From 2677 to 2956 Feet In thin sections of dolomite coming from 2677 to 2682 feet, and again from 2709 to 2735 feet below the surface, a form like a Nodosaria was noted. (Fig. 15 :b, c, d.) In another section of dolomite from between 2950 to 2956 feet appears a fossil which perhaps is a tangential section of the shell of a ribbed brachiopod, near its beak. (Fig. 15 :e.) ^^^>-'^; f'^^'^ T 3.^ -37 \ V^ a-d, X 40 e-f, X 20. The Deep Boring at Spur 85 From 2244 to 2264 Feet In the core of mostly oolitic dolomite taken at this depth, the following fossils were seen either in thin sections or macroscopically. a. Seen in thin sections. 1. Cellular tissue in a shred of bituminous yellow material im- bedded in dolomite. Figure 16: b. In the same section were many- smaller shreds of structureless yellow or brown material of similar nature and also two round bodies resembling spores. Figure 16 : a, c. 2. Trochammina sp.? Figure 16: e. i^fif^i- Ass ■ -. '■ / I -Tff I \ Figure 16. Fossils seen in thin sections made from a core taken from between 2244 and 2264 feet below the surface, a-k, m, X 40; 1, X 25. 3. Cross section of the disk of a flat spiral foraminifer. Am- modiscus? Figure 16: j. 4. Outline, in oblique aspect, of a foraminifer with biserially ar- ranged chambers. Figure 16: i. 5. Section of an Endothyra, parallel with disc. Figure 16: f. 6. Outlines of some chambers of a Nodosaria. Figure 16: d. 7. Bryozoa, several forms, seen from various angles. Figure 16: g, h, k, 1, m. b. Seen macroscopically. 8. Fragment of a brachiopod. 86 Bulletin of the University of Texas 9. A small part of the zoarium of a Fenestella, showing eight fenestrules, appears on the polished surface of a piece from the core. There are two branches in one mm. and about five dissepiments in two mm. A double row of zoecia was seen on each branch, four pairs in the distance of one fenestrule, with one dissepiment. 10. A small part of the surface of one bryozoan shows very minute pores of sub-equal size, about one-thirtieth mm. in diameter. They are vertical terminations of zoecia. The extent of the surface is about two square millimeters. 11. The three first whorls of a small flat-coiled shell, probably a Euomphalus. Its outer whorl measures less than two mm. across. 12. Parts of the valves of a small pelecypod. It measured less than two mm. in length, and had delicate lines of growth on the outer surface of the shell. It may have been a small Edmondia. From 1250 to 2042 Feet Another piece of core of oolitic dolomite was taken some- where between 1250 and 2042 feet below the surface, hence at least two hundred feet higher up in the column than the horizon from which the preceding fossils were taken. The smaller of these fragmentary fossils are incrusted, like oolitic spherules. These fossils are all from one and the same depth, wherever this be, within the limits known. The list is as follows : 1. Trochammina gordialis. Figure 17: b. 2. Nodosaria, sp. Figure 17: a. 3. A piece of a perforate form like Lituola bennieana Brady Figure 17: d. i! I and 2040 fL ^M^lf fl™*" ^/'^'^^ °I '=°'^? somewhere between 1250 dolomite X 40 '"'^- ^^^" '" *'''" ^^^*'°»« "f oo^ti-^ The Deep Boring at Spur 87 4. Various parts of bryozoa, resembling those taken at from 2244 to 2264 feet below the surface. Figure 17 : c, g. 5. Oblique section of some small gastropod. Figure 17: f. 6. Vertical cross section of the valve of some ostracod. Figure 17: e. ECONOMIC RESULTS Water This boring emphasizes the fact, long known, that water is very scarce in the Pennsylvanian and the Permian sedi- ments on the plains of the Southwest, and also that most of the water they contain is too salty for use. The sand- stone from 400 to 450 feet was so dry that casing had to be set to retain the water necessary for drilling. A small seep of water was noted near 2050 feet below the surface, but this was so small that when later the water was bailed down to 2300 feet, it filled up only 160 feet, over night. The well was then cased down to 1360 feet. Two other small seeps of water are reported by Mr. Minihan, one be- tween 2980 and 2995 feet, and another near 4260 feet below the surface. The experience in regard to water has been the same in other deep wells on the Plains from Childress to Upland. The chances are that, if any deep potable water will ever be found in the Red Bed area, it will come from below the Pennsylvanian, and perhaps below the entire Carboniferous, at some depth exceeding 500G feet. There can be little doubt that there are at least several hundred, and probably more than a thousand feet more of Pennsyl- vanian strata under the bottom of this boring. The ex- istence of such deep water is highly improbable. Discovery of Potash What may eventually be the most important economic result of this boring is that it has proved the existence in 88 Bulletin of the University of Texas the dolomite beds of a stratum, or horizon, from which comes a water sufficiently rich in potash to hold out induce- ment to prospective search for this mineral. The presence of much anhydrite and salt in the upper- most 1200 feet, in the section of the boring, caused the writer to suggest that an analysis of the water in the well be made to determine its potash content. At the time this suggestion was made, the hole had already been cased to below 1300 feet, and all water from strata above this depth had been shut off. A sample of water was taken on April 12, 1912, after the water had been bailed out dovra to 2200 feet below the surface. This water was analyzed a week later by S. H. Worrell, Chemist of the Bureau of Economic Geology and Technology of the University of Texas. His analysis showed the following mineral ingredients present in the quantities stated : Grains per U. S. Gal. Calcium sulphate 1,406.19 Calcium chloride 679.02 Magnesium chloride 219.20 Sodium chloride 3,410.55 Potassium chloride 324.14 6,039.10 In other words, the potassium chloride amounted to five grams per liter, and constituted 5.4 per cent of all solids. This being an unusually high content of potash in natural water, arrangements were later made for taking samples of water from different depths below the bottom of the 1350-foot casing. In June, of the same year, 14 such samples were obtained and later tested for potash. The depths at which these samples were taken and the deter- mined contents of potash in each are as in the table below, in which the April sample is included also. The Deep Boring at Spur 89 Potash content of fifteen samples of water taken at different depths in S. M. Swenson & Sons' deep boring at Spur, Texas: A B. C. D. E. 1 800 800 72.2 .5 ? 2. 1,360 300 59.1 .3 ? 3 1,390 1,390 61.9 .4 ? 4 _..1,500 (Drip water) 1,550 21.4 .4 ? 5. 1,600 1,600 42.9 .2 71 6. 1,800 1,390 94.4 .4 ? 7 1,830 1,830 47.2 .2 ? 8. 2,000 2,000 41.0 .2 ? 9. 2,200 (April sample) 2,200 324.1 6^4 ? 10 2,200 1,500 113.3 .5 71 11. 2,300 2,300 60.2 .3 74 12 2,400 2,400 69.6 .4 74 13. 2,600 1,500 86.2 .4 71 14. 2,690 2,400 29.1 .2 75 15. 3,000 1,500 43.6 .2 73 A — Depth at which sample was taken, in feet below surface. B — Depth to surface of water when sample was taken, in feet below surface. C — Grains of potassium chloride per U. S. gallon. D — Per cent of potassium chloride to total solids. E — Temperature of sample when taken, Fahr. Some of the samples were taken before much water had been bailed out of the well, while other samples were taken at intervals as the water was being bailed out. The table shows these particulars of the sampling, and it also gives some data on temperatures of the water samples when coming out of the well. The fact that the samples from 2200, 2600 and 3000 feet below the surface, bailed out when the water was standing at 1500 feet below the surface, had in each case a lower temperature than the samples taken at 2690, 2400 and 2300, when the water was standing at considerably lower depths, respectively, 2600, 2400 and 2300 feet below the surface, shows conclusively that the water from the different depths in the well had been mixed by convection currents caused by differences in tempera- ture in the upper .and the lower part of the hole. Each one of these analyses hence shows the potash content of a sample of water containing a mijcture of all soluble sub- 90 Bulletin of the University of Texas stances present anywhere in the wall of the well. It is not at all likely that the potash is uniformly distributed in this section of sediments 2650 feet thick. On the con- trary, it can be taken for granted that the mineral is confined to one or, at most, to a few distinct beds pro- duced at times favorable to the precipitation of this mineral in the sea in which the sediments formed, or introduced by ground water at some later time. As the convection of the water in the well is slow, owing to the small size of the hole and the slight difference between bottom and top temperatures, it is to be inferred that an ingredient in the solution supplied at a certain level would be present near that depth in greater quantity than at any other depth. The differences in the analyses made hence indicate the presence of a potash-bearing stratum somewhere near 2200 feet below the surface in this well. The sample having 324.1 grains per U. S. gallon was taken when work on the well ceased for a while, in April, 1912. All the other samples were taken two months later, before the work of drilling was resumed. The water had then been standing undisturbed for two months, and the potash-bearing in- gredient in the entire seepage had evidently been more evenly distributed through all the water in the hole. The maximum quantity of potash, in the 14 samples taken in June, is only one-third the quantity in the sample taken in April. It has been suggested that the general tendency of potash to diffuse by capillarity might readily account for the lesser amount present at 2200 feet after the well had been left undisturbed for two months. The potash would tend to "soak" into the walls of the hole, and be thus ex- tracted from the solution by capillary filtration. But we still find the greatest quantity of potash (113.3 grains) at the depth where the first sample was taken containing 324 grains per U. S. gallon. It is also quite significant that the sample showing the smallest quantity of potash was the only sample not really a mixture of all the water in the well. This was taken by suspending the bucket at 1500 feet wheii the water had been bailed down to 1550 feet. It consisted The Deep Boring at Spur 91 of water dripping from the wall of the hole and probably was a mixture of spilled water adhering to the wall of the well, and of some water trickling out from the rock above the depths where the bailer was hung, below the base of the casing. This sample contained only 21.4 grains of potash per gallon.* Analyses of Rock Samples Wishing to verify, if possible, the evidence from the water analyses, a number of tests for potash were made on the rock samples. It was evident that the chances for finding the original potash in the rock samples was very small, for two reasons. In the first place, the samples taken at the indicated levels were few and were selected to represent the principal kind of rock. Only one single sample was taken to represent all the material penetrated from 2128 to 2212 feet. This was a brown sandy clay. Should this bed contain the potash, it would most likely be confined to a few feet of the deposit rather than be present in the whole stratum. The sample taken from this bed consisted of fairly large cuttings and no doubt really represented but a few feet of the whole bed. Another sample represents 42 feet of rock, of nearly the same kind, from 2068 to 2110 feet. In the second place, from the finer particles, which might represent different depths within a greater thickness, any potash originally present could hardly have escaped being dissolved while in the circulating water carrying the returns, and most potash might have been lost in the same way from the entire sample, in each case. A number of samples were tested from the salt-bearing strata in the upper part of the hole. These served as a check on the lower samples. It may be worth the while to note that the samples from 2000 to 2300 feet were taken during the time from May to September, 1911. There was then no thought *The above account of the writer's observations on potash are taken, with slight changes, from his article on "Potash in the Permian of Texas," published in the American Fertilizer for December, 1912. 92 Bulletin of the University of Texas of looking for potash. The first test for potash in the water was made in April of the following year. The analyses of the rock samples from 732 to 1250 feet were made in Feb- ruary, 1914. All analyses were made by the Chemist of the Bureau, Mr. S. H. Worrell. The results are given below : TESTS FOR POTASH IN CUTTINGS AND PIECES OF CORE FROM THE SPUR BORING Depth of samples in feet below surface. Potash. Prom To 732 741 (cuttings) 914 931 (core) 931 932 (core) 958 962 (core) 962 1113 (core) 1113 1117 (core) 1117 1123 (core) 1174 1222 (cuttings) 1222 1235 (core) 1235 1250 (core) Near 2000 (cuttings) 2000 2200 (cuttings) 2042 2047 (cuttings) Trace 2047 2049 (cuttings) 2049 2063 (cuttings) 2064 2068 (cuttings) 2068 2110 (cuttings) Pronounced trace 2110 2126 (cuttings) 2128 2212 (cuttings) 2212 2214 (cuttings) 2214 2219 (cuttings) 2219 2241 (cuttings) 2244 2264 (core) 2271 2329 (cuttings) 2329 2331 (cuttings) 2331 2336 (cuttings) 2336 2338 (cuttings) 2392 2394 (cuttings) It can hardly be a mere coincidence that traces of potash were found in the solid rock only near the level where the potash content was highest in the well water. The very The Deep Boring at Spur 93 unusual amount of 324 grains per gallon also strongly sug- gests the existence of more than a mere slight impregnation in some stratum. Even after the potash had dissolved from the exposed walls of this stratum and had been diluted through a column of water three thousand feet high, it was present in an amount averaging 60 grains per gallon for all the water tested. It is to be recalled that salt was present in some rock samples, evidently as an original in- gredient, from 1600 feet, and again from 2244 to 2264 feet below the surface. Prospecting for Potash. Considering the great value of a workable deposit of potash, it seems worth the while to call attention to an- other circumstance in connection with these observations. In either direction north or south from Spur the forma- tions lie practically horizontal for at least a hundred miles, and the potash-bearing horizon, whether it be such or not in other places, must be at about the same depth as here, in these directions. It seems to the writer that the general conditions indicated in this boring, the existence of great salt beds and beds of anhydrite, together with the proven potash-bearing stratum, warrants an examination for potash in water from the same horizon in any boring made in this territory. Westward Dip of Strata East or west from Spur the depth to this horizon will be greater westward and less eastward. The elevation of the railroad depot at Spur is 2274 feet above sea-level. This is 666 feet higher than the elevation at Cisco, about 120 miles to the east-southeast. A line connecting these two points may be taken to follow the direction of the general dip of the formations to the west. The bottom of the well may be taken to represent the beds outcropping at Cisco. On this assumption, the general dip between Cisco and Spur, a distance of 120 miles, will be equal to the depth of the Spur 94 Bulletin of the University of Texas well, less the difference in elevation of the two places. This gives us a dip to the west of nearly 32 feet per mile. Our inability to fix the precise level in the Cisco formation reached in the boring may make this figure either a little too high or too low, but it cannot be far from right. Taking into consideration the general east slope of the land surface, which averages 6 feet per mile, any stratum should come nearer the surface at the rate of 38 feet per mile east- ward from Spur. Figure 18. Sketch map of a part of Texas, with contours showing the probable approximate depth, in feet below surface, to the Cisco formation, in the country between Cisco and Spur. The Deep Boring at Spur 95 Outcrop of the Potash-hearing Horizon Assuming now that this general dip is constant between the two points, and that the formations are continuous, the horizon which yielded potash in the Spur well should out- crop in a belt where the land surface intersects the dipping plane lying 2200 feet below the surface at Spur. This belt would extend through Haskell and Jones counties. It is not to be expected that potash should be found in any out- cropping rock in this belt, owing to surface leaching, but well waters there might show its former existence. Dr. Harper and Dr. Bailey of the School of Chemistry in the University of Texas have analyzed a number of water samples from wells near Haskell, and they have informed the writer that some of these waters contain an unusually large quantity of nitrate, which is not believed to be derived from the surface. It is suspected that this nitrate exists in the form of a potassium compound, as saltpeter. Along the hne of the Kansas City & Orient Railroad in these counties the potash-bearing horizon may be looked for at depths of from 100 to 400 feet. Potash in Other Well-waters in Texas For making a comparison between the Spur well-water and other well-waters in the Pennsylvanian and Permian formations of the north and central parts of Texas, the records of water analyses made by the School of Chemistry in the University of Texas have been examined. Seventeen analyses were found in which determination of potash have been made. All these have less than 8 grains per gallon, and average 2.16 grains per gallon. The records do not show what waters these were, in all cases, but they are all believed to have been well-waters. 96 Bulletin of the University of Texas Table Showing Potash Contents in Seventeen Samples of (Well?) Water from the Pennsylvanian and the Permian in the Northwest and Central Parts of Texas Potash in grains per U. S. gallon 1. Weatherford, Parker County, well 215 feet deep__ .09 2. Haskell, Haskell County. .30 3. Weatherford, Parker County, well 1425 feet deep .33 4. Arlington, Tarrant County .52 5. Weatherford, Parker County .61 6. Rochelle, McCulloch County 1.11 7. Mineral Wells, Palo Pinto County 1.21 8. Mangum, Eastland County 1.22 9. Burleson, Johnson County 1.39 10. Fort Worth, Tarrant County 1.40 11. Crazy Well No. 2, Mineral Wells, Palo Pinto County 2.45 12. Mineral Wells, Palo Pinto County 2.55 13. Thurber, Erath County 3.20 14. Lampasas, Lampasas County 4.34 15. De Leon, Comanche County 6.67 16. Mineral Wells, Palo Pinto County 7.52 17. Crazy Well No. 2, Mineral Wells, Palo Pinto County ;. 8.03 OIL AND GAS It has been shown that the dolomite from 1500 feet to 4100 feet below the surface frequently contains bituminous material. The driller reported a slight showing of gas near 4435 feet. It is believed that there are sufficient bitu- mens in these formations to have formed workable quan- tities, if the strata were such as to permit the oil and gas to accumulate in favorable structures. The Clear Fork beds are known to be bituminous in their outcrops. From the tests made on the bituminous contents of 27 samples of the rock, it is believed that it is safe to assume that The Deep Boring at Spur 97 the rocks examined contained a minimum of one-twentieth of a per cent of bitumens. This would be sufficient to make a layer a foot thick from 2000 feet of rock. The rocks of the dolomite beds, and still more the rocks of the Cisco, must be regarded as sufficiently bituminous to produce large accumulations of oil and gas under favorable struc- tural and lithological conditions. But the fact that the entire column of formations explored in the well below the Red Beds consist of compact sediments that do not even yield salt water, shows that the rocks are not in this locality sufficiently porous to have permitted the accu- mulation of any fluids they may have contained. The dolo- mite is compact and the sandstones are fine-grained, having their interstices filled with red clay. Everything consid- ered, the prospect for oil or gas in this vicinity must be regarded as decidedly discouraging, for the depth to which the exploration extends. INDEX Page. Acknowledgments 9 Ambocoelia plano-convexa , 83 American Fertilizer, The 91 Ammodiscus - 79, 84 Ammonia fumes 72 Analysis of dolomite core , 59 Of rock samples .___ 91 Of water 88 Anhydrite ..., .._. 53, 54, 55, 67 Secondary 68 Aparchites humerosus 83 Bailey, Dr. J. R 95 Bairdia beedei ___ 83 Bigenerina , 81 Bits used 20 Bituminous fumes 72 Brachiopod 83, 85, 86 Bryozoa 61, 76, 85, 86 Calcareous material 56 Calcite 71 Casing of Spur boring 8 Cellular tissue ,. 85 Character of Red Bed sediments 56 Chemical composition of dolomite 59 Cisco 93 Formation 74 Fossils in 76 Clastic texture of dolomite ^ 60 Clear Fork formation 53, 96 Climacammina ., 77 Contents of anhydrite, estimated 69 Coring 20 Cost of Spur boring. ^ 8 Crinoid stems 76 Crystalline texture of dolomite 57 Delaware formation 52 Dentalina ^ 77 Descriptions of samples 22-52 Dip of strata, westward ^...-— 93 Discovery of potash...... 87 Distribution of textures in dolomite 63 Dolomite 57 Beds 57 Crystals, sizes; of , 58 Dolomite oolite 27 Double Mountain formation 53 Driller's record 9 Economic results 87 Edmondia 86 Endothyra __ 79, 81, 85 Estimates on contents of anhydrite 69 Euomphalus '. _ .; , 86 100 Index Page. 86 Penestella 20 Fish-tail bit ]^g Flint " 52 Formations explored oc Fossils from 2244 to 2264 feet - ■ °^ From 2677 to 2955 feet - ,- — - °* In Sandy Dolomite Beds - T* In Shaly dolomite ■ - °* In the Cisco - ' ^g Notes on — ••- '„„ Fragmental texture of dolomite ----- °^ Fusulina '*' ^g Gas : ' Gastropods — - °^ Geinitzia post-carbonica - °^ Gumbo "" - ij° Gypsum ^°' '^ Hard rock - - }:° Harper, Dr. H. W — - - »^ Haskell County - ^° History of the Spur boring. ^ .- - 7 Interbedded sands - 64 Shale 65 Isinglass 1° Jaws of annelids ,. r 82 Jones, C. A - - 8, 9 County 95 Jonesina bolliaformis 83 Kansas City & Orient It. R - 95 Lagena - 78 Limestone 74 List of fossils 76 Lituola - - 86 Lower part of Red Beds...,- _— , 54 Methods of drilling 20 Middle part of Red Beds., — 53 Other minerals 71 Minihan, H. P 8, 9, 15, 18, 87 Mixing of returns. 21 Nodosellina 77 Nodosaria 81, 84, 85, 86 radicula ; : _.: 77 Oil and gas 96 Oolitic dolomite 27, 60 Spherules 60 Spherules, sizes of 61 Ostracods 83, 87 Outcrops of potash-bearing horizon 95 Panhandle 7 Pecos 7 Permian Red Beds ,. 52 Potash 87 Content of water 89 In Texas waters 95 In the Permian of Texas, article on 91 Potash-bearing horizon, outcrop of 95 Index loi Page. Prospecting for potash 93 Pyrite 72 Quartz 53^ 71 Rate of drilling 20 Red Beds 53 Returns in rotary drilling.... ._._ 2I Rhombopora : 76, 82 Rock samples 21 Analyses of 91 Roller bit 20 Saccammina _ 78 Salt '54, 72 Samples, description of 22 Of rock 21 San Angelo 7 Sands, interbedded 64 Sandy dolomite beds, fossils in 84 Selenite , 53 Septarian concretion 26 Shale .— 75 Interbedded .^ 65 Shaly dolomite beds, fossils in 84 Siliceous dolomite 29 Sizes of dolomite crystals 58 Of ooliths 61 Sketch map of part of Texas 94 Speed in drilling 20 Sponge spicules 82 Stacheia 80 Swenson, S. M., and Sons.. 7 Terms used, explanation of 18 Tests for potash in cuttings 92 Textularia jonesi 81 multilocularis 81 Texture of dolomite 62, 63 Triassic formation 53 Trochammina 78, 85, 86 Upper part of Red Beds 53 U. S. Geological Survey 9 Valvulina 79 palaeotrochus 79 rudis '.. 79 Water 87 Well waters, potash in 95 Westward dip of strata ^ 93 Wichita and Albany formations 53 Worrell, S. H 59, 88, 92 Wrather, W. E 8, 12 Plate 1. A. Thin section of oolitic dolomite from somewhere be- tween 1250 and 2042 feet below the surface. The spherules are closely appressed and the matrix in which they are imbedded is scant. It is seen in dim light lines. Much of the oolitic rock has been re- placed by anhydrite, which appears as light striated tracts in the section. This is one phase of the rock described under number 74 (4) in the descriptions of well samples. Vertical section. X 40. Plate 1. B. The rock described under number 74 (3) in the well samples. The structure of this rock is such as to suggest that it may have been an oolite, from which much of the original material has been dissolved, causing the spherules to flatten. Vertical section, X 43. Plate 2. Vertical section of dolomite from 1600 feet below sur- face. See description of sample number 77. X 40. Plate 3. Vertical section of oolitic dolomite, a considerable part of which has been replaced by anhydrite. The spherules are ap- pressed and many appear to have been reduced by solution externally so as to conform to the shapes of adjacent spherules. For further description see sample 78. X 40. (The vertical axis extends from left to right.) Plate 4. A. Photograph of a piece of core from 2250 feet below the surface. Reduced to two-thirds natural size. Anhydrite and quartz appear light. For description see sample number 90. B. Vertical section extending through part of a concretion of anhydrite with dim outlines of straight structures which probably are spicules of sponges. The rock, darker part of section, shows a dim stratification gently flexed upward against the anhydrite concre- tion. See description of sample 94. X 20. Plate 5. Vertical section of a dolomite showing the outlines of numerous organic fragments of small size imbedded in a matrix of more coarsely crystalline dolomite. The fragments show an oolitic coating and some oolitic spherules are present. A few of these are filled with anhydrite. The matrix appears light in the photograph. X 20. (The vertical axis extends from left to right.) Plate 6. Vertical section through another phase of the rock shown in plate 5. In this phase organic fragments are few, or almost absent, and the dolomite matrix is filled with oolitic spherules. The interiors of a few spherules are filled with anhydrite, and appear light in the plate. The darker appearing spherules consist of crystals of dolomite of very small size. X 20. Plate 7. Vertical section through a third phase of the dolomite shown in plates 5 and 6. This phase shows a mixture of oolitic spherules and organic fragments in a matrix of somewhat coarsely- crystalline dolomite. Some few spherules are filled with dolomite crystals of the same size as the crystals in the matrix. X 20. Plate 8. A. Vertical section of oolitic dolomite from between 2609 and 2624 feet below the surface. . Anhydrite has replaced the material inside many of the spherules and the matrix is dolomitic. X 40. B. Vertical section through another phase of the oolitic dolomite shown in A, plate 8. Anhydrite has in this instance replaced most of the material in the matrix and the spherules remain as dolomite. X 40, Missing Page ^^^KifiMFfflP'? 1^^^%^^ l||nH|^, M '•sgjs^ pH^^^H BpM ^HKpf^^p P^' ' ^^^^^^B' "^^WBB HteB ^^HH^Bw9^^H^Ci->« . -j^g^'*^ j^SK hH [^^^^P 1 ■m ^^^R^H HH^^^^^HH^ka ^ji Plate 10. A. Horizontal section of dolomite from near the depth of 3245 feet. The rock has an obscure oolitic structure. X 40. n+oi BoMinn r\f oi-wo+nllino rtrAomite from near the depth Plate 11. Horizontal section of dolomite from near 3405 feet below the surface. The dolomite crystals are gathered into clusters which are separated by a reticular matrix containing some secondary anhydrite. This condition appears to be the beginning of a change, which in a more advanced stage has resulted in the production of a rock consisting mainly of anhydrite but with crystals of dolomite scattered like the centers of these clusters in the rock mass. The two phases are closely associated in the samples. X 80. Plate 12. B. Horizontal section of dolomite from near 3490 feet. For description see under sample number 213. The tubular struc- tures are cut obliquely by the section. X 40. C. Horizontal section of dolomite from near 3645 feet. Traces of organic fragments and of oolitic spherules are preserved in the texture of the rock. Some anhydrite is present. X 40. ^^^^^^^ M ^^^^^^^ Plate 13. A. Horizontal section of dolomite from near the depth of 4070 feet. The crystals are of uniform size. X 80. B. Horizontal section of dolomite from near the depth of 4085 feet. This rock shows some streaks of bituminous material which appear dark in the section. X 80. '^^^I^BI'^''^'^^^S^'l 1- i ^ ^Iw' JH K j^H^^^^^^^^^^^NBBS^^^^gKaJB Lj^^^^^ES K |P jin Mft^N' '^^WHSaMfy Jfi^ » ^^VHPHRHI ^^"'^^1 ^^^ 1 p.r Plate 14. Horizontal section of limestone from near the depth of 4285 feet. The light areas are clear calcite, filling crinoidal and other organic fragments. X 40. ■ — h Cr> C/- en s: r=5 cr Cr> — * - ^ :^ cs C=7 C^ rs C~:> :Z3 c^ =»<^ c^ C^ cz> . J, :3 =S <7Q C^ =3: i:^ X X; ^ r5 c^ C^ Ci-