ILLUSTRATIONS XV 



Clapp : Page 



Figure 3 — Geological structure of a portion of the volcano anticline 

 in Wood, Ritchie, Wirt, and Pleasants counties, West 



Virginia 564 



" 4 — Structure map of a typical oil and gas field in West Vir- 

 ginia 566 



" 5 — Hypothetical section across south end of MciKittrick oil 



field, California, 567 



" 6 — Ideal section in a pinching sand 567 



" 7 — Hypothetical section through the Coalinga oil field of 



California 568 



" 8 — Structure map of gas pool in Clinton sand near Wooster, 



Ohio 568 



" 9 — Map illustrating the occurrence of petroleum on struc- 

 tural terraces in southeastern Ohio, according to Sub- 

 class III (c) ., 570 



" 10 — Structure map of a locality in Osage County, Oklahoma. 576 

 " 11 — Cross-section of a typical saline dome oil field in Texas. 579 

 " 12 — Hypothetical cross-section of a volcanic plug in the 



Coastal Plain of Mexico 586 



" 13 — Cross-section of oil field at Baicoi, Roumania 588 



" 14 — Plan and cross-section of a dike in Mexico 590 



" 15 — Hypothetical cross-section of an intrusive bed in the 



Coastal Plain of Mexico 591 



" 16 — Section through Shirvanskaya wells, Maikop field, Russia . 592 

 " 17 — ^Geologic sections through the Los Angeles oil fields, Cali- 

 fornia 595 



" 18— Section through Bibi-Eibat field of Baku, Russia 596 



" 19 — Cross-section of the Bustenari field, Roumania 597 



" 20 — Cross-section in McKittrick field in California 599 



MiiXER : 



Figure 1 — Map of Appalachian region 619 



" 2 — Curves showing relation of oil production in geology .... 627 

 " 3 — Comparative stratigraphic columns of Ohio, West Vir- 

 ginia, and Pennsylvania 629 



" 4 — Geological section from Cincinnati anticline to the Alle- 

 gheny front 637 



" 5 — Generalized section showing relation of the distribution 

 of Appalachian oils of various gravities to the zone 

 of dynamic disturbance and to the fixed-carbon per- 

 centages in coals 643 



Kay: 



Figu: e 1 — Map showing location of Illinois oil fields in 1916 656 



" 2 — Unconformity between the Chester and Pottsville forma- 

 tions 658 



" 3 — Idealized section through a dome , 662 



" 4 — Sketch showing significance of unconformities and the 



"spotty" chara' tev of sand in Colmar area 665 



