CAKBONIFEKOUS COAL. 95 



At the extreme northern end of the district, on the west slope of Diamond 

 Peak and north of Garden Creek, in a very similar limestone, the beds 

 yielded as follows: 



Fusilina cyliiidrica. Productus prattenianus. 



Chaetetes, sp. f Productus semireticulatus. 



Zaphrentis (fragments). Spiriferina cristata. 



Ptilodictya (Stenopera) carbonaria, ! Athyris subtilita. 



Ptilodictya (Stenopera) serrata, ! Eetzia mormon i. 



A complete list of fossils from the somewhat restricted fauna of the 

 Upper Coal-measures will be found at the end of this volume. 



Carboniferous Coal. In the first range to the east of the Eureka District, 

 Carboniferous formations extend for miles along the edge of the valley 

 which in a study of Paleozoic rocks present some points of more 

 than ordinary interest. It is the only range in the Great Basin where coal 

 of Carboniferous age has been discovered in anything like a well defined 

 seam of sufficient thickness to encourage exploration, although beds carry- 

 ing small amounts of carbonaceous matter are known in one or two other 

 localities in central Nevada. Two outcrops of this coal are known and 

 considerable exploration has been undertaken in order to determine the value 

 of the coal seams ; one is situated on a low flat hill known as Pancake Ridge, 

 and the other on Bald Mountain, which stands out prominently at the southern 

 end of the Humboldt Range. Pancake lies about eight miles to the west- 

 ward of the Eureka District in a mass of low ridges connecting the 

 Humboldt Range with the White Pine Mountains. Rising above the plain 

 occurs a body of rhyolite, beyond which is a low ridge of coarse conglom- 

 erate followed by a second ridge somewhat higher than the first with an 

 intervening valley or shallow depression. Along the western base of this 

 second ridge an exposure of drab clay shales crops out only a few feet in 

 thickness, striking approximately north and south with a low dip to the 

 east rarely exceeding 10. This clay carries a seam of lignite varying 

 from 10 to 18 inches in width which may be readily traced for nearly !.">(> 

 feet along the line of outcrop. Both above and below this coal seam are 

 alternating layers of bituminous shale and purer day shale ronformably 

 resting upon a bed of coarse conglomerate. Above tin- rlay shales comes 



