350 PROCEEDINGS OF THE CALIFORNIA 



The zinc blende which is found in small quantities at Whisky Hill, and the vit- 

 reous copper also to some extent, appear to have escaped decomposition. The 

 copper ores appear to have been confined to a portion of the deposit, as is indi- 

 cated in the section exhibited, while the auriferous sulphuret of iron has been 

 co-extensive with the ore channel, the cubical cavities left by the decay of its 

 crystals being found in all the outcrops both in the quartz and in the ' calico 

 rocks,' resulting from the decomposition of feldspathic and talcose or chloritic 

 constituents. 



Accompanying the entire mass of decomposition at both localities, occur 

 both gold and silver, disseminated with remarkable uniformity in all parts ot 

 the orey ground. At Whisky Hill, films of metallic silver are visible upon 

 the talcose masses stained green by malachite or chrysoeolla ; the gold is rarely 

 seen in situ, being mostly obscured by the very rusty and highly-stained char- 

 acter of the associated materials. But it is rare that on washing a small quan- 

 tity of any of the coutents of these great deposits, gold is not found in an- 

 gular grains or small ragged masses, from the size of a few grains' weight, to 

 impalpable dust. Nuggets of several pennyweights occur occasionally. This 

 gold has evidently accompanied the sulphurets and been left in its present posi- 

 tion and condition by their decomposition. There can be little doubt that the 

 gold of the gulches adjoining these deposits has been derived from them. At 

 Whisky Hill, the gulch gold ceases to be found as soon as the limits of this 

 deposit are passed, and the same is true at Quail Hill. The occurrence of depos- 

 its of this nature throughout the range of the foot-hills, seems to offer the best 

 solution which has suggested itself of the origin of the placer gold which is 

 found in situations so far removed from the gold belt of the upper Sierras, and 

 away from sources usually recognized as those to which placer gold may be 

 referred. 



Experiments made by myself and by others on a considerable scale, the de- 

 tails of which will appear elsewhere, show that the amount of the precious 

 metals disseminated in the average mass of vein stuff and decomposed mate- 

 rials of every name at Quail Hill, is considerably in excess of the general aver- 

 age tenor of gold veins in California. The mean of my own trials gave to the 

 ton of 2,000 lbs. by assay: 



Gold $35.14 



Silver 15-08 



$50.22 

 While from the working of carefully prepared averages in considerable quan- 

 tity by milling process, the tenor of the precious metals was : 



Gold $29.18 



Silver 5 - 91 



335.09 



The extremely friable condition of the entire mass of these auriferous mate- 

 rials renders their extraction and treatment easy and comparatively inex- 

 pensive. 



