204 GEOLOGY OF THE EUKEKA DISTRICT. 



anticline with corresponding beds upon both sides of the axial plane. 

 Between the ancient shore-line to the west and the Humboldt Range 

 on the east, there appears to have been a deep meridional trough-like 

 depression in which all the beds from the Eureka quartzite up to the top of 

 the Devonian were deposited. How far north Avard they can be traced con- 

 tinuously is still a matter of conjecture, but we know that the Devonian 

 beds occupy large areas along the valley of the Mackenzie River. To the 

 south this narrow channel or trough apparently widens out into a broad 

 bay or open sea. 



To the southeast of Eureka, in the White Pine Mountains, the Eureka 

 quartzite, and both the Trenton and Niagara members of the Lone Moun- 

 tain epoch are well developed on the northeast end of Pogonip Ridge, and 

 the Devonian on Treasure and Babylon hills. The sequence of strata, 

 together with the associated fauna from the base of the Pogonip to the 

 Diamond Peak quartzite, may be easily correlated in the two localities. 

 Still farther southward, on the east side of Pahranagat Valley, both the 

 Upper Silurian and Devonian are exposed in a great thickness of limestones 

 bordering the valley. In the uplifted block at Quartz Peak, in the Pahran- 

 agat Range, we have Pugonip, Eureka, Trenton, and Niagara all well 

 exposed, but neither the upper nor lower horizon is shown in its full devel- 

 opment. 



Special mention should be made of the grand exposure of limestone 

 found south of Quartz Peak. Here we have over 8,000 feet of conform- 

 able beds starting in with the Niagara at the base, passing through a great 

 thickness of Devonian, and continuing on up into beds characterized by 

 a rich fauna of the Lower Carboniferous. In this section the White 

 Pine shale and the Diamond Peak quartzite are wholly wanting. While 

 this series of beds shows in some respects the closest resemblance to the 

 Eureka section, it is also significant as indicating an equally strong resem- 

 blance to the massive body of Wasatch limestone carrying Silurian, Devo- 

 nian, and Lower Coal-measure limestones without intervening siliceous 

 belts of any considerable thickness. 



Such exposures on a grand scale are sufficient to show a very great 

 development of Silurian and Devonian rocks stretching for long distances 

 from southeastern Nevada well up toward the northern part of the State, 



