68 GEOLOGY OF THE EUREKA DISTEICT. 



of C. C. Canyon and extends eastward until the upper members of the 

 Nevada limestone are submerged beneath the great basalt flow of Basalt 

 Peak and the Strahlenberg. 



County Peak Section — 5,200 feet. 



Feet. 



1. Evenly bedded, bluish gray limestone, with interbedded 



bauds (if dark limestone 600 



2. Irregularly bedded, blue limestone, with intercalated seams 



of quartzite 1, 600 



3. Yellowish gray quartzite, with narrow bands of gray silice- 



ous limestone • 100 



4. Massive beds of siliceous limestone alternating with beds of 



pure gray limestone and narrow bands of quartzite 700 



5. Massive, gray vitreous sandstone 100 



6. Siliceous limestone in massive beds more or less siliceous in 



thin bands, carrying shaly limestone belts 800 



7. Grayish white, vitreous sandstone 100 



8. Gray and blue limestone well bedded 500 



9. Light colored, compact quartzite changing from red to white 50 

 10. Massive, light colored limestone without bedding, more or 



less siliceous 650 



5, 200 



In this section the lower 700 feet are assumed to belong to the Lone 

 Mountain, giving 4,500 to the Devonian. This leaves about 1,500 feet of 

 the Upper Devonian strata wanting as compared with the beds in the region 

 of Modoc Peak. These upper beds are again well shown at Newark Moun- 

 tain and Mahogany Hills. 



White Pine Shale.— C(jnforiuably overlviug the Nevada limestone occurs a 

 heavy body of black shale, which has been designated as above, it having 

 been iirst recognized as a distinct horiztm in the White Pine mining district 

 to the southeast of Eureka. It occupies a clearly defined stratigraphic 

 position with a marked change in the character of sedimentation and a 

 fauna distinct from both the underlying and overlying horizons. 



There are only two large bodies of White Pine shale at Eureka, but 

 they lioth offer excellent rock exposures, one west of Newark Mountain, 

 the other east of Sentinel Peak. The shale is best studied west of Newark 

 Mountain (atlas sheet vi), where it forms the entire rock mass thi-ough which 



