12(5 GEOLOGY OF THE EUREKA DISTRICT. 



two sections. In the ridge section there are 1,300 feet of strata below this 

 shale belt before reaching the quartzite, and about 3,000 feet above the 

 shale. The Atrypa Peak section gives 2,000 feet from the shale to the 

 quartzite at the base, and nearly the same thickness from the shale up^■\•ard. 

 This shale carries an abundance of characteristic species and, although a 

 larger number were obtained on the slope of Atrypa Peak, there is no 

 question that the fauna is identical in both. 



At the head of Lamoureux Canyon there is a ridge of limestone, 

 striking northwest and southeast, which rests unconformably against the 

 quartzite. Not far above the quartzite a small collection of typical fossils 

 was made, amply sufficient to prove that the beds belong to the Devonian. 

 On the summit of the high peak east of Jones Canyon is another excellent 

 locality for the collection of Devonian species, but no specific forms were 

 found here not recognized elsewhere. Owing to local faulting, the exact 

 position of these latter beds could not be determined other than that they 

 belonged ttt the lower Nevada limestone. They are well bedded, strike 

 across the ridge and dip westerly. 



Jones Canyon lies wholly in the Devonian limestone and offers some 

 good exposures of rock, but no continuous section at all comparable to those 

 described in the region of Atrypa Peak. 



White Mountain.— The couutry between Atrypa Peak, and the Prospect 

 Peak fault culminates in White Mountain (9,941), the highest point Avest 

 of Prospect Ridge, with which it is connected on the northeast by a high 

 ridge of quartzite. From Spring Valley a fairly uniform slope of 1,500 

 feet extends to the summit of White Jlountain, made up -^^-holly of Pogonip 

 limestone, which stretches eastward and falls away gradually for about 800 

 feet to a high saddle in the range, beyond which it descends in a narrow 

 belt for another 300 feet to Mountain Valley. Here it is cut off by a fault 

 bringiiig up a narrow strip of Nevada limestone lying between the Pogonip 

 on the one side and the Eureka quartzite on the other. It is possible that 

 this fault may be onlj^ an extension northward of the Pinnacle Peak fault. 

 In the neighborhood of the saddle the quartzite encroaches on the lime- 

 stone. The structm-e of the mountain is difficult to make out, but the 

 limestone is everywhere surrounded by the quartzite, long belts of the 



