(F) Anticlines in a part of the Musselshell Valley, Musselshell, Meagher, and Sweetgrass Counties, Mont., by C. F. Bowen (published 1919). (J) Asphalt deposits and oil conditions in southwestern Arkansas, by H. D. (K) Coal south of Mancos, Montezuma County, Colo., by A. J. Collier (pub- 31 PLATE VII. A, Green River formation on north side of Argyle Canyon, Utah; Page. B, Green River formation on west side of Parachute Creek, Colo.. VIII. Fossil vegetable matter of oil shale of Green River formation (gen- X. A, Oil shale northeast of Watson, Utah; B, Thin-bedded oil shale.. XI. Abandoned shale retort near Juab, Utah... XII. Map showing distribution of oil shale in Uinta Basin, Utah. In pocket. XIII. Map of a portion of the Pawhuska quadrangle, Okla., showing XIV. Records of wells drilled in the northwest corner of the Pawhuska quadrangle, Okla., compared with the upper portion of the record of the Caney deep well and the general stratigraphic sec- tion of the Pennsylvanian rocks in the Independence quad- XV. Records of deep wells at Caney, Neodesha, and Iola, Kans., show- ing the character of the upper part of the pre-Pennsylvanian In pocket. XVI. Geologic map of Lake Basin field, Mont.. In pocket. XVIII. Diagrammatic representation of the nonpersistence of lithologic units in the Lake Basin field, Mont...... XIX. A, False-bedded Eagle sandstone cut off by a fault in the SE. sec. 23, T. 3 N., R. 22 E., Mont.; B, The Judith River formation as it is exposed in the very much dissected area 14 miles south XX. A, Sandstone at top of ridge in Bearpaw shale near section line between secs. 33 and 34, T. 2 N., R. 21 E., Mont.; B, Basal portion of ridge-forming sandstone in Bearpaw shale near middle of sec. 35, T. 2 N., R. 21 E., Mont... XXI. A, View looking southeast from point of Eagle sandstone near the northeast corner of sec. 9, T. 3 N., R. 20 E., Mont.; B, Northward-sloping hillside where fault cuts through the Eagle, Claggett, and Judith River sandstones into Hailstone Basin, XXII. A, Small thrust fault in Eagle sandstone in the SE. † sec. 18, T. 3 N., R. 23 E., Mont.; B, Fault in southwest corner of sec. 7, XXIII. Faulted anticline of Eagle sandstone, looking southeast from a point on the sandstone in the Bearpaw shale in the northwest corner of sec. 16, T. 2 N., R. 25 E., Mont.... XXIV. Geologic map and sections of Birch Creek-Sun River area, In pocket. XXV. Geologic map and sections of a part of the Musselshell Valley, In pocket. XXVI. Structure map of the Nesson anticline, Williams County, N. Dak., and sections showing lignite beds of the Fort Union formation XXVII. Geologic map of middle Salinas Valley, Cal.... In pocket. PLATE XXX. A, B, Physiographic features of Santo Tomas coal field, Tex..... XXXII. A, B, Views of mines in Santo Tomas coal field, Tex XXXIV. Map showing the exposures of coal of Mesaverde age near Mancos, XXXV. A, View up Weber Canyon, Colo., from its junction with Mancos XXXVI. A, Lone Cone and Point Lookout, near Mancos, Colo., from the XXXVII. Sections of the lower part of the Menefee formation, showing its XXXVIII. Sections of Mesaverde coal beds, group A, near Mancos, Colo.... Colo.... XL. Geologic map of the Lost Creek coal field, Morgan County, Utah. FIGURE 1. Sections showing underground relations of rocks along Atchison, 2. Section showing underground relations of rocks in plateau north 4. Diagram showing structure of Dakota sandstone in Syracuse and 5. General section across Nebraska from Omaha to the Rocky Mountains. 7. Sketch section from Pine Ridge Agency, S. Dak., to Black Hills... 10. Section across central South Dakota from the Sioux quartzite 15 11. Diagram showing structure under parts of Harding and Perkins 12. Section along Arkansas Valley from Pueblo to Canon City, Colo.... 14. Diagram showing structure in the Apishapa quadrangle, Las Ani- Page. FIGURE 15. Map of the anticline on Old Woman Creek, Converse County, Wyo. 16. Section across the anticline on Old Woman Creek, Converse County, Wyo...... 24 25 17. Ideal section to show relations of flexures in an older formation, 26 18. Syncline in older strata persisting, although considerably flattened 26 19. Diagram illustrating processes of manufacture in the Scottish 21. Hypothetical section illustrating the terracing in the northwestern 59 22. Generalized stratigraphic section showing rocks exposed in north- 61 23. Cross section illustrating lenticularity of sandstone beds.............. 62 65 25. Sketch illustrating conditions observed in railroad cut between 65 26. Hypothetical cross section showing changes in the stratigraphy that would make observations on the outcrops of beds of small value.... 71 27. Cross section showing possible position of anticline below valley and of syncline below hill..... 77 28. Sketch illustrating the importance of contouring lower bed rather than upper bed when determining structure... 79 29. Structure contours representing a small anticline, based on 10 ele- 81 30. Structure contours representing a small syncline, based on the same 81 31. Key map showing relation of Lake Basin field, Mont., to major structural features of the region..... 134 32. Index map showing position of Birch Creek-Sun River area, Mont. 33. Columnar section of portions of Kootenai formation and Colorado shale... 151 158 34. Diagram illustrating three types of structure produced by reverse 170 40. Sections of Santo Tomas coal bed. 39. Detailed sections of rocks exposed in Santo Tomas coal field, Tex., 38. Sections showing general stratigraphy of the Santo Tomas coal 37. Map showing general position of the Santo Tomas coal field, Webb 35. Index map showing location of the Salinas Valley-Parkfield 36. Geologic map of Pleyto oil district, Cal... 999 241 253 261 264 265 266 42. Map of Colorado showing the location of the coal field south of Man- 43. General view of the mountain tops near Mancos, Colo.. 293 294 312 |