THE BASIN PROVINCE 167 



"When compared over large areas these layers are found to be variable as 

 to both character of the bed and quantity of phosphoric acid present, not only 

 vertically but horizontally, and yet in many respects they are rather uniform and 

 constant in character and have throughout the field certain common characters." 



The Park City formation extends nearly as far north as the Weber and 

 Quadrant quartzites. 



Yeatch 1 described briefly the occurrence in southwestern Wyoming. 

 Here the formation occurs in the Tunp Range, about 15 miles west of 

 Kemmerer. It is " a series of very arenaceous thin-bedded limestones which, 

 from its stratigraphic position, approximately represents the Upper Coal 

 Measures limestone of the Fortieth Parallel Survey." It is very probable 

 that the same formation occurs in the Crawford Mountains, which extend 

 to the southwest into the type area of the Park City formation or very 

 near to it. 



In eastern Wyoming the Park City horizon is represented by the Embar 

 limestone; the equivalence of these beds seems to be more and more definitely 

 established as work in the region progresses. 



Woodruff, 2 in describing the Lander region, says that the Embar forma- 

 tion occurs in the \Vind River Mountains adjacent to the Lander oil field. 

 "About half of the Embar formation consists of limestone, most of it mas- 

 sive and crystalline, but certain members of this half are shaly and cherty; 

 the other half of the formation is shale." 



The upper member, as given in the section below, is evidently above 

 the Park City formation and is Triassic. The lower part may be called 

 Permo-Carboniferous. 



Feet. 

 Limestone, shaly and tan-colored; sandy at top; lies immediately below the red shales at the base 



of the Chugwater formation. (Triassic) 18 



Limestone, massive, crystalline, slightly cherty, and with distinct major joints 23 



Limestone, concretionary, cherty, slightly shaly 45 



Shale, drab, sandy 4*> 



Sandstone, bituminous (Permo-Carboniferous fossils) 5 



Limestone, shaly, crystalline 5 



Shale (?) 24 



Shale 21 



Limestone, massive, impure, with well-developed major joints 73 



Limestone; contains occasional thin, shaly limestone layers 90 



Darton 3 in his description of the Big Horn Mountains speaks as follows 

 of the Tensleep and Embar: 



(Page 34.) " Tensleep Sandstone. Its thickness varies from 50 to 100 feet 

 in the northeastern portion of the region to over 200 feet in the east-central 

 portion and from 250 to 300 feet to the south and west. * * * 



1 Yeatch, A. C., Geography and Geology of a Portion of Southwestern Wyoming, U. S. 



Geological Survey, Professional Paper No. 56, p. 50, 1907. 

 * Woodruff, E. G., and C. H. Wegemann, Lander and Salt Creek Oil Fields, Wyoming, 



U. S. Geological Survey Bull. 452, p. 12, 1911. 

 1 Darton, N. H., Geology of the Big Horn Mountains, U. S. Geological Survey, Professional 



Paper No. 51, 1906. 



