422 



SUPPLEMENTARY INVESTIGATIONS IN THE GRAVEL REGION. 



plentiful signs of wear, but are not very much rounded. In some cases I saw broken and angular 

 fragments of slate rock lying close by the side of smooth quartz. Some of the boulders at this 

 mine are peculiar in composition. Some are conglomerates or breccias, and one, as Mr. Colgrove 

 told me, which was found a hundred feet above bed-rock, was a mass of cemented gravel, with a 

 smooth and rounded surface. As would be expected, where boulders are so common, clay streaks 



are very rare. 



The white gravel above the blue stratum is made up almost exclusively of quartz. It would 

 hardly be an exaggeration to say that nothing but white quartz is to be seen upon the present 

 irregular surface of Dutch Flat Hill. The masses vary in size from an inch or less in diameter up 

 to eio-ht or ten feet. They are usually smooth, and in some places very much worn, though 





generally not enough to obliterate the original irregularities of surface, This quartz shows very 



frequently hollows, or vugs, containing good crystals and crystal facets. As a rule, it is barren 



of gold. 



The gravel on Plug Ugly Hill was a white quartz, like the upper stratum at Dutch Flat, con- 

 taining in addition a small quantity of easily decomposed pebbles, probably of slate. 



At Little York the deep gravel carries some extremely large boulders, partly of white quartz, 

 partly of blue quartz, and partly of a highly silicious rock which shows indistinct slaty characters. 

 This rock is quite unlike ariy of the bed-rock of the vicinity, which is an easily cleavable slate. 

 On the Empire Hill bed-rock there are also large piles of boulders of white or blue quartz together 

 with two or three varieties of bluish slate, and in the gravel, at a considerable height above bed- 

 rock, above much of the fine gravel, there are large angular boulders, which show but little trace 

 of wear. It is difficult to account for all these phenomena by the action of running water alone, 

 and it is also difficult to account for the local accumulations of special varieties of boulders. The 

 presence of such large boulders in unusual quantity must have interfered very seriously with the 



regularity of the hydraulic washing. 



The opening at the Waloupa bank is very much larger than it was in 1870, extending over an 

 area of at least 800 feet in length, in a direction S. 40° E. (magnetic), by 300 in width. There is 

 no bed-rock exposed excepting at the lower end of the mine. At the upper or northwestern end 

 the top gravel alone lias been worked, and the bank is about one hundred feet in height. At the 

 lower end a little blue gravel appears near the bed-rock. The upper gravel is reddish in color and 

 it carries considerable washed quartz, though composed principally of an easily decomposed meta- 

 morphic slate and other allied rocks. There is some sand, but no pipe-clay of any consequence, 



The principal mining operations at You Bet and Chicken Point are now carried on by the 

 Nevada Hydraulic Mining Company, which owns in this neighborhood nearly one thousand acres 

 of mining ground. The upper gravel — that at Chicken Point— -is composed of white and blue 

 quartz with some admixture of slate and other easily decomposed rock. There are a few irregular 

 sand streaks, but there is no pipe-clay, no cement, no blue gravel. Black sand occurs abundantly. 

 The gravel has been washed away back to the base of the Sugar Loaf, under which it appears to 

 take the shape of a wedge, which will soon come to an end if work is pressed in that direction. 

 The face of the bank shows several distinct layers, the thickness of which I estimated by the eye 

 alone, without stopping to make accurate measurements. Beginning at the bottom there are in 

 succession strata of 



Gravel and sand . 

 Sand . . 



Green gravel 



Yellow sand, or clay 



Volcanic ash (the so-called " chalk ") 



feet. 



20 



25 

 15 



12 



40 



The top of the Sugar Loaf is a hundred feet or more above the " chalk." The green, gravel 

 stratum is distinctly traceable along the face of the bank under Chalk Bluff. The diagram (Plate 

 P, Fig. 2) shows the probable position of the gravel under the lava. 



The Buckeye Hill gravel is practically exhausted, only a few Chinamen being at work there at 



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