1868. | Gold in California. 317 
perature of about 95° F., and appears to have been the agency 
_ by which the various mineral substances formed in the cavities were 
brought to the surface. Sulphur is being constantly deposited on 
the surfaces of the various fissures, and is sometimes mixed with 
cinnabar, although more frequently with pulverulent silica, often 
blackened by the presence of a tarry hydro-carbon. With these 
traces of gold and silver are stated to sometimes occur. 
On the sides of the various fissures, gelatinous silica is found 
coating chalcedony, in various stages of induration, from a pasty 
condition, to that of the hardest opal: cinnabar is also found in thin 
bands, and occasionally even in veins of considerable thickness. 
Where the bituminous matter before referred to occurs in the largest 
quantities, the mass becomes black and friable, the cinnabar im such 
cases being replaced by metallic mercury. 
In another locality of the same character, about ten miles distant, 
a vein of compact silicious rock, about ten inches in thickness and 
evidently of very recent origin, yielded by assay silver to the value 
of nearly three pounds per ton, together with traces of gold. 
The above and other similar facts appear to lead to the conclusion 
that auriferous quartz veins are the result of aqueous agencies, and 
that their mineral and metallic constituents have, as well as their 
silicious matrix, been deposited from solution. 
The extraction of auriferous quartz from the veins in which it 
occurs is conducted in precisely the same way that the mining of 
tin and copper ores is carried on in this and other European coun- 
tries, and some of the workings have already reached considerable 
depths. Among the deepest mines in the state is Hayward’s, in 
Amador County. This has now reached a depth of more than 1,300 
feet on the inclination of the vein, and is, at the present time, more 
profitable to the proprietors than at any former period. The amount 
of veinstone annually raised is usually about 90,000 tons, and the 
yield of gold, on an average, from fourteen to eighteen pennyweights 
per ton. It may be here remarked that the productiveness of the 
quartz veins of California has not been found, as was at one time 
prognosticated, to decrease in depth; but that, on the contrary, 
many mines which were, near the surface, comparatively unproduc- 
tive, have materially improved as lower levels are attained. It is 
also a fact worthy of notice, that all remuneratively auriferous gold 
veins contain notable quantities of iron pyrites and other metallic 
sulphides, and that the association of these minerals with gold is so 
constant, and so remarkable, as to be, in all probability, the result 
of oe chemical action regulating the distribution of the precious 
metal. 
The constant presence of iron pyrites in auriferous veins, and, 
whenever so occurring, its invariably enclosing a certain amount of 
gold, suggest the probability of this sulphide being, in some way, 
