124 ANNALS NEW YORK ACADEMY OF SCIENCES 



The Park City formation lies between the Weber quartzite and the 

 red beds of the Woodside shale, and, in the type locality on the north 

 side of Big Cottonwood Canyon, it has a thickness of about 600 feet. 

 As exposed there, it consists largely of limestone with intercalations of 

 sandstone and quartzite. Its differentiation below from the Weber quartz- 

 ite is readily made by the appearance of calcareous layers which soon give 

 way to a thick bed of limestone. As before stated, in the central Wa- 

 satch this transition indicates continuous deposition from Weber into 

 Park City time. The occurrence of limestones nearly as extensive as 

 those of the Park City formation within the typical Weber is well known, 

 and this suggests that the Park City beds mark the recurrence of one 

 of these periods of limestone formation when typical marine conditions 

 prevailed. 



In the older reports, the upper coal measure limestones represent this 

 horizon. They were especially noted for the abundant fauna which they 

 carry and have usually been regarded as of Carboniferous age. Of late, 

 however, some tendency is shown to place them higher in the series, 

 possibly in the Permian. In the correlation table here given, the inter- 

 pretation of the various workers is placed at the right and that of the 

 writer on the left. This view is supported by the fauna and stratigraphic 

 relations which are better shown in Dry Canyon, to the north, than in 

 Big Cottonwood Canyon. There is in that section between 500 and 600 

 feet of red shales and brownish sandstones between the Meekoceras beds 

 of the Lower Triassic and the upper fossiliferous portion of the Park 

 City formation. These seem to rest with low angular unconformity upon 

 the Park City beds and carry an abundance of a single species of Lingula 

 in the beds next to the contact. Faulting is frequent in this area, and 

 the apparent discrepancy in dip between the two sets of beds may be due 

 to that cause, but a search failed to reveal evidence of faulting. From 

 the nature of the beds of red shale and brownish sandstones, it might be 

 expected that they should bear a relation of unconformity, or at least 

 disconformity, to the typical marine beds upon which they rest. From 

 the widespread occurrence of Permian red beds in the west, these are 

 thought to be of that age. The fauna of the upper part of the Park 

 City formation indicates their Carboniferous age. Prominent forms are : 



Productus multistriatvs 



Productus suhcostatus 



Spiriferina pulchra 



Spirit er cameratus 



Linaiilodiscina utahensis 



Athyria (Seminula) argentea 



(Rhynchonella) Pupnax swallowiana 



