200 



GEOLOGY OF THE EUREKA DISTRICT. 



fault brings the Lower Coal-measures up against the Pogonip, organic 

 remains characteristic of both epochs being found within a few hundred 

 yards of each other, with the intervening space occupied mainly by 

 igneous extrusions along the fault-line. Here, however, they have been 

 brought into their present position by profound orographic displacement. 



The Wasatch and Kanab Sections. The Wasatch Range, which shuts in the 

 Great Basin on the east, combines, in a marked manner, many of the geo- 

 logical characters of both the Rocky Mountains and the Basin ranges. In 

 structure, however, it is closely related in its essential features to the ranges 

 of Utah and Nevada. There is exposed in the range a very remarkable 

 section of conformable beds, extending through 30,000 feet of sediments 

 and exhibiting nearly every geological period from Lower Cambrian to 

 Permian. ^ For the purpose of comparison a section constructed by the 

 Geological Exploration of the Fortieth Parallel is reproduced, as it shows 

 not only certain resemblances, but also striking differences in the sequence 

 beds from the section as exposed at Eureka : 



Wasatch section, Utah: 30,000 feet; conformable. 



PERMIAN, 650 feet . 



CARBONIFEROUS, 

 14,000 feet 



DEVONIAN, 2,400 feet. < 



SILURIAN, 1,000 feet ... 

 CAMBRIAN, 12,000 feet . 



Permian 



Upper Coal-measure limestone . 



Weber quartzite 



Lower Coal-meas- "1 

 ure limestone . . I Wasatch 



Waverly f limestone . 



Nevada limestone J 



Ogden quartzite. 

 Ute limestone . . 



Cambrian 



650 

 2,000 

 6,000 



7,400 



1,000 

 1,000 



12,000 



Clays, marls, and limestones; shal- 

 low. 



Blue aud drab limestones; passing 

 into sandstones. 



Compact sandstone and quartzite; 

 often reddish; intercalations of 

 lime, argillites, and conglomerate. 



Heavy bedded blue and gray lime- 

 stone, darker near the base, with 

 siliceous admixture, especially 

 near the top. 



Pure quartzite, with conglomerate. 



Compact, or shaly, siliceous lime- 

 stone. 



Siliceous schists and slates, quartz- 

 ites. 



In the Wasatch section the 12,000 feet of metamorphosed schists, 

 slates, and quartzites probably occur below the Cambrian beds as exposed 

 at Eureka, except so far as they may be represented in the upper members 

 by the Prospect Mountain quartzite, while the great thickness of Cambrian 

 limestones and shales of the Eureka section is included within the 1,000 

 feet of Ute limestone in the former section. Again, at Eureka the Permian 

 at the top of the section is wholly wanting and the Upper Coal-measures, 

 which in other parts of Nevada attain a development of nearly 2,000 feet, 



