FOSSIL BUTTE. 195 



tions are readily determined. At this locality, in beds below the Eureka 

 quartzite, Mr. Walcott made the following collection: 



( )rthis perveta. Subulites sp. ? 



Orthis tricenaria. Orthoceras sp ? 



Orthis pogonipensis. Ortlioceras (Aiiiiulated species). 



Strophornena fontinalis. Leperditia bivia. 



Modiolopsis occidens. Ceraurus sp. ! 



Modiolopsis pogonipensis. Illamus crassicauda. 



Raphistoma acuta. Bathyurus pogonipensis. 



Murchisonia, 2 sp.* Pleurotomaria lonensis. 



Fossil Butte. At Fossil Butte, 10 miles north of Hyko, on the east side 

 of Pahranagat Valley, the Pogonip is again seen overlain by the Eureka 

 quartzite. The butte stands out as an elevated ridge, but presenting an 

 exactly similar succession of strata as seen along the east side of Prospect 

 Mountain, Pogonip Ridge, and the western base of Lone Mountain. In the 

 limestone occur the following species: 



Receptaculites mammillaris. Metoptoiua phillipsi. 



Orthis tricenaria. Ecculiomphalus, like E. distans. 



Strophornena fontinalis. Orthoceras rnulticameratum. 



Triplesia? sp.? Endoceras multitubulatum. 



Leperditia bivia. Modiolopsis occidens. 



Maclurea subannulata. Modiolopsis pogonipensis. 



Maclurea, 2 sp., undet. Illaenus crassicaiida. 



Taken together these two groups from Bennett Spring and Fossil 

 Butte carry the more marked fauna of the Upper Pogonip. Overlying the 

 quartzite occur some light gray limestones, without organic remains, but 

 resembling the Lone Mountain beds. Along the east side of Pahranagat 

 Valley limestone ridges extend for several miles. The beds have been 

 much disturbed and have undergone considerable faulting, preventing accu- 

 rate sections^ but it is estimated that there are from 2,000 to 3,000 feet of 

 limestones exposed. They are more or less siliceous, weathering reddish 

 brown and brownish gray. The lower members may possibly belong to the 

 Lone Mountain series. Near Hyko there is an exposure of shaly limestone, 

 overlain by massive beds of dark arenaceous limestone, carrying a Devonian 



