SECTION ACJKOSS LONE MOUNTAIN. (H 



Orthis lonensis. Maclurea annulate. 



Orthis perveta. Maclurea carinata. 



Orthis tcstudiiiiiria. Maclurea sp.? 



Streptorhynchus minor. Cyrtolites sinuatus. 



Coleoprion minuta. llla-nus sp.? 



Resting upon the Pogonip comes the Eureka quartzite, but with less 

 thickness than the corresponding beds at Eureka. Immediately above the 

 quartzite, with but little development of transition beds, occur the light 

 colored siliceous limestones, measuring at least 2,000 feet. These beds form 

 the greater part of the western slope of the mountain, and are so character- 

 istically shown as to make the local name of Lone Mountain an appropriate 

 one to designate the epoch. In the lower limestones, resting directly upon 

 the quartzite, the Trenton fauna appears to be wanting, and it is by no 

 means certain that the beds are represented. At all events the bluish gray 

 limestone characteristic of the Trenton at Eureka and White Pine has not 

 been recognized. On the other hand, throughout the entire epoch evi- 

 dences of organic remains are exceedingly meager and confined to silicified 

 corals imperfectly preserved. The Niagara coral, Halysites catemilatus, which 

 usually occurs several hundred feet above, is found here within 50 feet 

 of the quartzite. 



The light colored siliceous limestone passes up gradually into the dis- 

 tinctly bedded Nevada limestone of the Devonian, which forms the summit 

 of the ridge, and as the strata dip eastward make up the greater part of the 

 eastern slope. It is by no means certain, however, that a displacement of 

 strata does not extend along the eastern face of the uplifted mass, the base 

 of the ridge not having been examined. 



Mr. C. D. Walcott made the following section across Lone Mountain 

 (see Fig. 2): 



Feet. 



1. Dark gray limestone, with brown and variegated layers iuterbedded. 



Typical Devonian fauna. (Nevada limestone.) 1, 500 



2. Siliceous bluish gray limestone breaking up into shaly bands carrying 



abundant fossils of the Lower Devonian. (Nevada limestone.) 200 



3. Siliceous limestone, light brown, gray, and buft' in color, with Hull/site* 



catenulatitit near the base; passing up into beds almost white, with blue 

 and gray tints, followed by alternating dark and light beds. (Lone 

 Mountain limestone.) 



