Chapter XIII. 



JURASSIC. 



Color, greenish blue (horizontal ruling). 



Symbol, 9a. 



Distribution: Central America, Mexico, CaUfornia, Oregon, Alberta, and parts of Alaska. 



Content: Jurassic limestone and shale of Nevada; Mariposa slate. Sierra Nevada; Franciscan 

 formation. Coast Kange, CaUfornia; Jurassic of Mexico; Chinitna shale and Tuxedni sand- 

 stone ("Enochkin formation"), also Naknek formation, of Alaska Peninsula. The Jurassic 

 of Humboldt Range, Nevada, and the marine Sundance formation of the Rocky Mountains 

 are mapped with the Triassic, as "Triassic and Jurassic" (9), the areas being too small 

 to distinguish the system separately. 



Jurassic areas. 



Page. 



D 16 Guatemala (not mapped) 549 



E14 Oaxaca 549 



E-F 14 Puebla and Vera Cruz 551 



F 14 Sierra de Catorce, San Luis Potosi, Mexico 551 



F 17-18 Cuba 552 



G 13-14 Sierra de Mazapil, Zacatecas and Ooahuila 552 



H13 Texas 554 



I-K 10-11 Coast Range, California 554 



J 10 Sierra Nevada, California 555 



J 11 Humboldt Range, western Nevada 556 



J 12 Southern Utah and plateau district, Colorado (mapped as Triassic and Jurassic). 556 



K 10 Upper Sacramento Valley, northern California, and southern Oregon 561 



K 12 Southwestern Wyoming (mapped as Triassic and Jurassic) 565 



K 12-13 Northwestern Colorado (mapped as Triassic and Jurassic) 566 



K-L 13 Wyoming and South Dakota (mapped as Triassic and Jurassic) 567 



L 11 Eastern Oregon (mapped as Triassic and Jurassic) 571 



L 12 Montana and Wyoming (mapped as Triassic and Jurassic) 571 



Ir-M 10 Olympic Peninsula 572 



M 10 Washington and British Columbia (not mapped) 573 



M 11 Southwestern Alberta 574 



M-O9-10 Western British Columbia (not mapped) 574 



4-5 Alaska Peninsula 574 



8 Atlin Lake, British Columbia (mapped as Triassic and Jurassic) 576 



P 8 Lewes River, Yukon Province (not mapped) 576 



R 3 Northwestern Alaska.' 577 



R-S 27 Northeast coast of Greenland 577 



D 16. GUATEMALA. 



DoUfugs and JMont-Serratt ^ cited the identification of Jurassic fossils reported 

 to have been collected on the shores of Lake Isabel in eastern (juatemala and 

 contained in the collections of the CoUegio Tridentino, but Sapper does not mention 

 any such occurrence, and the rocks described by DoUfuss and Mont-Serratt under 

 the Jurassic appear to be Cretaceous. 



E 14. OAXACA. 



At Tlaxiaco, in Oaxaca, according to Felix and Lenk,^^^" Jurassic strata consti- 

 tute the greater part of the Cerro Titania. At the base are thin-bedded clay slates 



549 



