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-measures 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 conformably on the 

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

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

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

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



Section CD-EF. This section is constructed across the central portion of 

 the Eureka Mountains (atlas sheets vn and vin), and stretches in an east 

 and west line from Antelope to Newark valleys. It presents more of the 

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

 sections, as it passes through 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 the 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 there 

 is a considerable but unknown thickness of valley accumulations with the 

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

 against the flanks of Spanish Mountain 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 summit. The moun- 

 tain presents in general a broad anticlinal fold, although broken by m;mer- 

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

 in the transverse section, giving a small exposure of Lone Mountain beds 

 overlying the quartzite. On the east slope of Spanish Mountain, where the 

 beds dip away steeply to the east, there is a small exposure of highly 

 siliceous limestones without bedding partially concealed by Quaternary 



