DIAMOND MOUNTAINS. 27 



stones of the Upper Devonian form the remainder of the steep slope for 

 about 1,000 feet and then stretch far out into the valley in a line of low 

 hills and isolated Imttes, still dipping toward the east. The entire western 

 side of the mountain, including the summit of the ridge, dips uniformly 

 toward the west, and is in turn overlain by the White Pine shales through 

 which Hayes Canyon has been eroded. On the north side of Newark 

 Mountain these flexible shales curve around to the northeast and form the 

 east base of Diamond Peak, only the uppermost beds of the Nevada lime- 

 stone here appearing above the level of the valley, the remaining portion 

 of the Devonian beds upon both sides of the fold having dropped completely 

 out of sight. 



Diamond Peak rises above Newark Valley over 4,000 feet, with an 

 exceptionally steep slope, the White Pine shales presenting smooth rounded 

 ridges along the base of the mountain. The shales are overlain by a great 

 thickness of rough and rugged Diamond Peak quartzites, followed by the 

 Lower Coal-measure limestones which for a long distance form the summit 

 of the ridge. In its structure the Diamond Range is in strong contrast with 

 the anticlinal structure of Newark Mountain, presenting a synclinal fold 

 whose axis lies in the Lower Coal-measures. The identical series of beds 

 found dipping into the peak on the east side come in again on the west 

 side, but with a reverse dip, except that the White Pine shales are not 

 brought to the surface, owing to a longitudinal fault which extends along 

 the west side of Diamond Peak, completely cutting them off and bringing 

 up still higher Carboniferous formations than those found near the summit. 

 From the axis of the anticline on the east slope of Newark Mountain diag- 

 onally across Diamond Peak there is exposed an admirable section, includ- 

 ing Nevada limestones, White Pine shales, Diamond Peak quartzites, and 

 Lower Coal-measure limestones. The geological importance of this section 

 lies in the fact that it offers, across the middle of the Paleozoic rocks, a con- 

 formable and continuous series of beds rarely found elsewhere, uniting the 

 upper Paleozoic with the great development of Silurian and Cambrian rocks 

 beneath. From Bold Bluff, at the southern end of Diamond Peak, the New- 

 si rk fault brings the Lower Coal-measures against the White Pine shales, the 

 entire development of Diamond Peak quartzite having been displaced along 



