GEOLOGICAL CROSS-SECTIONS. 213 



a uniform dip to the west at an angle of 25° or 30^ with the horizon. With 

 the observed dips and strikes they measure 3,700 feet. As described in the 

 chapter devoted to the descriptive geology of the Diamond Range the 

 Lower Coal-measui*es rest unconformably upon the White Pine shales, the 

 dip of the beds in the latter epoch reaching an angle of 50° along the 

 Newark fault. These latter shales are shown to lie conformabl}' on tlie 

 Nevada limestone along the line of Hayes Canyon. The anticlinal stnict- 

 ure of Newark Mountain is not brought out in section, as the axis of the 

 fold only comes in near Avhere the border of the map cuts off the easterly 

 dipping strata. The latter stretch far out into Newark Valley. 



Section CD-EF.— Tliis sectiou is Constructed across the central portion of 

 the Eui'eka Mountains (atlas sheets vii and viii), and stretches in an east 

 and west line from Antelope to Newai-k valleys. It presents more of the 

 salient structural features of the region than is shown in either of the other 

 sections, as it passes tlnough the broadest part of the Mahogany Hills, the 

 flat-topped summit of Spanish Mountain, the steep anticline of Prospect 

 Peak, the syncline of Spring Hill, and the easterly dipping strata of 

 County Peak, and crosses the Spring Valley, Hoosac, and Pinto faults. 

 The section starts in at the western end of the Mahogany Hills and runs 

 obliquely across the strike of tlie beds, which lie nearly horizontal or 

 inclined at very low angles. In order to bring out the structural features 

 of the country, the Lone Mountain beds are represented as underlying the 

 Nevada Devonian above the base line of the section. At Dry Valley thei*e 

 is a considerable but unknoAvn thickness of valley accumulations with the 

 Nevada limestones on the west side and the Lone Mountain beds resting 

 against the flanks of Spanish Moimtain on the east. These Lone Mountain 

 beds lie against the Eureka quartzites which come to the surface on the 

 slopes of Spanish Mountain long before reaching the suunnit. The moun- 

 tain presents in general a broad anticlinal fold, although broken by numer- 

 ous cross-faults and dislocations. One of these dislocations is represented 

 in the transvei'se section, giA'ing a small exposure of Lone Mountain beds 

 overljang the quartzite. On the east slope of Spanish ^Mountain, where the 

 beds dip away steeply to the east, there is a small exposm-e of liighly 

 siliceous limestones without bedding partially concealed b}' Quaternary 



