158 GEOLOGY or THE EUREK-A DISTRICT. 



The following- section gives the broader divisions of the beds from 

 base to summit, including those exposed on Newark Mountain, as the 

 Nevada limestones on Diamond Peak are shown only to a very limited 

 extent: 



Feet. 



1. Bluish gray distinctly bedded limestones 1, 000 



2. Green and brown and chocolate colored clay shales, with interbedded 

 siliceous bauds and cherty beds 5(t0 



3. Dark gray quartzites, compact conglomerates, with interbedded layers 

 of jasper and siliceous grits. Near the base narrow belts of blue 

 limestone, carrying Productiis semlreticulatus 2, 500 



f 4. Black argillaceous shale, more or less arenaceous and similar to the 



lower black shale h 000 



5. Compact, flue grained sandstone, with minute dark siliceous pebbles 



scattered through the beds 100 



5 <( 6. Black argillaceous shale, with fine intercalated beds of arenaceous 



shale. These shales crumble on exposure to atmospheric influence. . 500 



Q 7. Reddish gray shaly calcareous beds . . 100 



8. Dark gray heavily bedded siliceous limestone, passing into bluish gray 



limestone, in places finely banded 3, 500 



Total 9,200 



The importance of this section lies in the fact that it gives over 9,000 

 feet of conformable limestones, shales, and sandstones of Upper Devonian 

 and Lower Coal-measure strata, the best section as yet recorded from 

 this portion of the Paleozoic series in Nevada. It will be noticed that at 

 the base of this series of beds less than one-half of the thickness of the 

 Nevada limestone is represented, and at the top onh' about one-quarter of 

 the entire thickness assigned to the Lower Coal-measures is exposed on the 

 summit of Diamond Peak. 



Along the summit of the range occupying the axis of the fold the 

 Coal-measure limestone extends for a long distance, and on Diamond Table, 

 at their southern limit, they present a bold body of nearly horizontal beds, 

 300 feet in thickness, resting directly upon the quartzites. In Water 

 Canyon, which drains the southern end of Diamond Peak, the position of 

 these two formations is well brought out, erosion ha^ang carved a mag- 

 nificent amphitheater, with abrupt walls, 2,000 feet into the quartzite. In 

 the bottom of the canyon the White Pine shale comes out beneath the 

 quartzites, all three formations being shown in the canyon walls. 



Scattered throughout these limestones may be found Coal-measure 



