92 



THE AUEIFEEOUS GEAVELS OF THE SIEEEA NEVADA. 





the Cement Mill Claim on the east side of Damascus Canon and one fourth of a mile from the hotel, 

 the gravel in the channel, where worked, is composed of quartz and volcanic pebbles and boulders 

 mixed together, with much volcanic sand ; the pay-stratum lies always close to the bed-rock, and 

 is only a foot or two thick. Toward the head of Indian Canon, above the Mount Pleasant Flat, 

 many tunnels have been driven into the hill, developing a system of shallow channels which 

 seemed to come down from the central portion of the ridge obliquely to the present canon. The 

 stratum of gravel here was thin, ranging from a few inches to two or three feet in thickness, and 

 was covered with volcanic debris, while in places the volcanic matter closed down directly on to 

 the surface of the bed-rock ; which, however, was everywhere water-worn, whether any gravel in- 

 terposed between it and the volcanic, or not. i 



At the Eed Point, near Damascus, the quartz gravel stratum is said to be twenty feet thick. 

 The material is wholly quartz, but not so much rounded as in the Mountain Gate Channel. 



At Sterrett's Claim, on the left bank of Sailor's Canon, the gravel appears to be pretty deep, 

 possibly 150 feet, and consists of a very heavy "wash," that is, of large boulders only partially 

 rounded by water ; these boulders are generally very quartzose, but not pure quartz. They seem 

 rather to be a pebbly conglomerate metamorphosed into a jaspery mass. 



In Yule's Claim, at Startown, the gravel is well washed and water-worn, and the boulders are 

 of the same general character as the harder portions of the bed-rock, and do not appear to have 

 come from any great distance. The thickness of the gravel is from thirty to fifty feet, and it is 

 immediately overlain by the volcanic debris, which forms all the crest of the ridge. 



At Nick Anderson's Mine, just below Last Chance, the gravel is whitish and contains consider- 

 able quartz, but many of the boulders are of the same character as those in the two chief claims at 

 Startown (Yule's and the Morning Star). 



At the English Claim on the west side of the ridge fronting El Dorado Canon, near Deadwood, 

 the pebbles and boulders consist of a great variety of metamorphic rocks. The bed-rock is well 

 washed and the gravel is only a few feet deep, varying from one to seven feet, and overlain by 

 volcanic debris, much of which is more or less clayey in texture and of somewhat the color of 



* 



chocolate. 



In the Eeed Mine, near Deadwood, the gravel varies from an inch or two to six or eight feet 

 in thickness, averaging probably about eighteen inches. It contains some pretty large boulders, 

 some of which will weigh several tons. Some of these boulders are composed of white quartz ; 

 but most of them are of metamorphic sandstone, very compact, and hard and bluish in color. 

 Immediately above the gravel comes a layer of what the miners call " chocolate," which is from 

 nothing to five feet in thickness, averaging about three feet. This material looks like a mass 

 of consolidated clay and has very nearly a chocolate-brown color. It appears to be a mixture of 

 clayey matter with almost impalpably line sand, and is probably a volcanic mud-flow. The order 

 of succession, at a point where an air-shaft rises to the surface, in this mine is as follows : 



Cement and volcanic conglomerate . 

 Quartz gravel with fine scales of gold . 

 " Cement," proper .... 

 Quartz gravel, auriferous 

 " Crav Cement " . 

 " Chocolate " . 



Gravel, auriferous, six to eight feet in some places, averaging . 

 Bed-rock 



Feet. 



(50 or 80 to surface. 



7 



40 



6 



30 



4-5 



1* 



At the Eattlesnake Mine, near the Reed Mine, and near Deadwood, the gravel in the middle 

 channel ranges from fifteen to twenty feet deep, and is similar in character to that in the Eeed 

 Mine, only it is much deeper, and contains large quantities of detached and more or less rounded 

 Fragments of bed-rock. Many of the boulders in this gravel are of hard blue sandstone, and some 

 are of quartz, weighing, occasionally, as much as two or three tons. Above the gravel is a thin 



