164 ENVIRONMENT OF VERTEBRATE LIFE, ETC. 



to a fauna widely dispersed over the West and traceable, it is believed, even into 

 Alaska, Asia, and eastern Europe. The other western faunas of about the same 

 geologic age are largely composed of representatives of the Brachiopoda and 

 Byrozoa, especially of the Productidae and Spiriferidse. Thus there is little 

 common ground for comparison, but though the abundant and characteristic 

 features of the phosphate fauna are peculiar to it, where a common ground for 

 comparison does exist an agreement can be found to a considerable extent, 

 and some of the less abundant forms have a wider distribution. These western 

 faunas have not been studied in detail and in many localities the rocks in which 

 they occur have not been discriminated into formations and named, so that it is 

 possible to speak of them only in a general way. If, however, we eliminate the 

 beds of recognized lower Carboniferous age, such as the 'Wasatch limestone' of 

 Utah (lower part), the Red wall limestone of the Grand Canyon section, and the 

 Baird shale of California, and also certain younger divisions such as the ' Permo- 

 Carboniferous ' of the Wasatch Mountains and surrounding region, the Permian of 

 the Grand Canyon section, the Guadalupian series of Texas, and, perhaps, a few 

 others, we have left a group of rocks, as already remarked, which is widely dis- 

 tributed throughout the West (including Alaska) and which constitutes the major 

 portion of the Carboniferous representation in that extensive area. The fauna 

 of these formations thus tentatively grouped together, though presenting many 

 local modifications, can, in a general way, be correlated with the Gschelian fauna 

 of the Ural Mountains, some of the American assemblages presenting truly 

 remarkable resemblances to those of Russia." 



The Park City formation, which Schultz 1 regards as equal to the Phos- 

 phoria formation and the upper part of the Wells formation in eastern 

 Idaho, is exposed on both the northern and southern sides of the eastern 

 and western ends of the Uinta Mountains. A geologic map showing the 

 exact location of the outcrops is given in his publication. His description 

 of the Park City formation is as follows : 2 



" PARK CITY FORMATION (PENNSYLVANIAN AND PERMIAN). 



'The Weber quartzite is overlain by a series of limestones of Pennsylvanian 

 and Permian age, with which are associated some calcareous sandstones, shales, 

 and chert. This formation contains the phosphate deposits and has yielded the 

 bonanzas that during the last decade have made the Park City mining district, 

 in the Wasatch Range, Utah, a famous lead and silver camp. The formation 

 consists for the most part of thin-bedded arenaceous limestones and shales, with 

 some massive limestone ledges near the base. Although consisting chiefly of 

 limestones, it may be subdivided into four more or less distinct members which 

 are usually recognizable in different parts of the field: (i) the upper thin-bedded 

 shaly gray limestone series, which weathers readily, forming depressions, and at 

 a distance has the appearance of a clay or shale bank; (2) the upper or cherty 

 limestone beds, which contain a large percentage of concretionary chert nodules 

 and lenses; (3) a phosphatic shales series, in which bands of chert and limestone 

 occur; and (4) the lower limestone member, consisting primarily of massive light 



1 Schultz, A. R., A Geologic Reconnaissance of the Uinta Mountains, Northern Utah, U. S. 



Geological Survey Bull. 690-0, p. 76, 1918. 

 * Loc. cit., p. 46. 



