ALHAMBKA HILLS. 153 



against it. On the uorth side of the Silverado iauh, between the White 

 Pine shale and the rhyolites occurring at the head of Rescue Canyon, is a 

 triangular block of limestone inclined to the east. This block of limestone 

 lies on the east side of the Rescue fault, conformably underlying the White 

 Pine shale and offering ample structural evidence that it belongs to the 

 liighest beds of the Nevada horizon. The amount of faulting along Silver- 

 ado Canyon has never been determined, but probably does not exceed a few 

 hundred feet, which is additional evidence that the Century Peak beds 

 belong to the upjier portion of the Devonian. South of Century Peak there 

 is a decided break in the strata and the entire limestone ridge dips off 

 toward Fish Creek Valley, with a northeast and southwest strike. 



Aihambra Hills.— The low ridge of limestoue designated as the Alhambra 

 Hills Hes to the east of the Ceutui'y Peak ridge and is connected with the 

 latter by a continuous body of limestone. North of this connecting ridge 

 Quaternary deposits lie between these hills and Century Peak ridge, 

 but they are of no great thickness and undoubtedly overlie a depressed 

 area of limestone. Alhambra Hills rise but a few hundred feet above 

 the plain. They present a dull, monotonous, arid aspect, with but few 

 scattered trees and without soil. The hmestones belong to the upper 

 members of the Nevada horizon and are massive, distinctly bedded, grayish 

 blue rocks. But little time was devoted to the search for fossils, but such 

 as were found denoted the upper beds of the Nevada and were mostly 

 corals similar to those found in the neighborhood of Centmy Peak, associ- 

 ated with the ever present Atrypa reticularis. Beyond this identification of 

 the age of the beds the Alhambra Hills present no special geological in- 

 terest. A few mineral veins penetrate the limestone, but so far as known 

 are imaccompauied by rhyolite intrusions. The latter rock, while it prob- 

 ably encu-cles the Alhambra Hills, does not appear to enter the limestone 

 body. 



White Pine Shale Area.— There is little that need be said about this area in 

 addition to the observations presented elsewhere in discussing the geological 

 position and the paleontological evidence of the age of the White Pine 

 shale. On page 81 will be found a description of the strata across the 

 entire thickness of shales and sandstones, at least until they are overlain 



