54 



AMADEUS W. GRABAU 





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appearance of the so-called Ogden 

 quartzite and conglomerate,which bears 

 internal evidence of continental, chiefly 

 river, origin; and to all appearance 

 represents the sand and gravel wash 

 which followed the retreating sea 

 westward, and which was probably in 

 large part derived from the basal Uinta 

 quartzites, with which the "Ogden" 

 seems to become confluent in the east- 

 ern Uintas.^ This quartzite rests on 

 higher beds in the western sections 

 than in the eastern, thus showing the 

 same relationship to the underlying 

 series that is exhibited by the St. 

 Peter sandstone. In the western 

 Uintas it is underlain by 1,200 feet 

 of shales, regarded as Cambric, though 

 the highest beds may represent the 

 Lower Ordovicic. In the Wasatch 

 Mountains the Ute limestone, 2,000 

 feet thick, and of Cambro-Ordovicic 

 age, lies between the "Ogden" and Uinta 

 quartzites. In the Eureka section of 

 central Nevada, the Pogonip limestone, 

 2,700 feet thick, underlies the Eureka 

 quartzite, the westward continuation 

 of the Ogden. The Pogonip repre- 

 sents, in its basal portion, the transi- 

 tion beds from the Upper Cambric, 

 but corresponds mostly to the Beek- 

 mantown of eastern North America. 

 Beneath it are 6,200 feet of fossiliferous 

 shales and limestones of Cambric age. 

 Here, as in the eastern region, succes- 



I Berkey, Bull. Geol. Soc. Amer., Vol. XVI, 

 pp. 517-30. 



