502 DESCRIPTIVE GEOLOGY. 



shales, marls, fine sandstones, and thin paper-shales. Thin, red, compact 

 sandstones form the overlying beds, passing down into hard, red marls and 

 shales, underneath which are more sandstones, banded red by oxide of 

 iron, and in turn underlaid by finely-laminated gray shales, with thin beds 

 of indurated clay. The peculiar carbonaceous zones, as well as the paper- 

 shales, so closely relate these to the Elko shales that they have been referred 

 to the Green River Eocene series. No organic remains of fish or insects, 

 such as characterize the Elko beds, were obtained here, and the reference 

 rests entirely upon lithological resemblances. 



Overlying the upturned Tertiary beds are others approximately hori- 

 zontal, and made up largely of comminuted volcanic material. They 

 appear to extend westward across the valley, and to form the divide 

 between the Gosi-Ute Desert and Thousand SpringValley, stretching south- 

 ward as far as Toano Pass. At the pass, the depression is occupied 

 by the latter deposits, mainly lavender-colored pumice-like beds, exceed- 

 ingly friable, but distinctly bedded, and composed largely of rhyolitic, sili- 

 ceous, and feldspathic material, in which are some sandy, earthy seams 

 re-arranged and deposited under water. The town of Toano lies directly 

 upon these Pliocene strata, and the more favorable beds are used to advan- 

 tage for building purposes. The rock appears to harden upon exposure. 



Gosi-Ute Range. — This range extends from Toano Pass southward to 

 Mount Pisgah in an unbroken line of upheaval, with an almost true north 

 and south trend. As thus limited, it measures about 65 miles in length, a 

 narrow ridge scarcely averaging 6 miles in width. It presents the first 

 long, continuous range west of the Great Desert, and forms the bound- 

 ary of that great depression, its long slopes rising gradually above the 

 plain on the eastern side, but falling away much more steeply on the other 

 toward Gosi-Ute Valley, which lies 1,300 feet above the level of the desert. 

 The range is one of extreme dryness and nearly barren of vegetation, there 

 being but little soil either on the slopes or in the basins, while arborescent 

 growth is confined to scattered dwarfed pines and stunted mountain-mahog- 

 any (Cercocarpus ledifoUus). 



Geologically, the Gosi-Ute Range is made up of granites, quartzites, 

 and limestones ; all the beds of the latter formations being referred to the 



