ORIGIN OF GOLD NUGGETS. 330 
conclusion that auriferous veins are under certain conditions 
deposited from siliceous solutions, but also to explain the action 
by which many of the slates of the auriferous period may have 
become metamorphosed and silicified.” 
“We are indebted to Dr. Oxland, formerly manager of the 
works belonging to the Borax Lake Company, Lake County, 
California, for the following note on the occurrence of gold and 
silver in that locality :—“In the Sulphur Bank at Borax Lake, 
sulphur is constantly in course of formation, with the evolution 
of aqueous vapour, carbonic acid, and boracic acid, but without 
any sulphuretted hydrogen, which might have been expected to 
be present. The smell of carbonic acid is remarkably pungent. 
The gaseous matters issuing from the “ Soffioni” in gentle blowers 
are usually at the temperature of about ninety-five degrees Fahr. 
They appear to be the agency by which gold, silver, mercury, and 
iron are brought up from below and deposited in cavities near the 
surface. Sulphur is deposited on the sides of the cavities, either 
in groups of crystals or in highly translucent amorphous masses 
of a beautiful light lemon-yellow colour. Sometimes the sulphur 
is intermixed with cinnabar, but more frequently with very fine 
crystals of iron pyrites, and with pulverulent silica in masses 
blackened by some hydro-carbon which is difficult to isolate. The 
iron pyrites may be separated by dissolving off the sulphur with 
bisulphide of carbon, and washing off the silica with water. It 
is found associated with silver and a trace of gold. 
“On the sides of the cavities of the blowers, gelatinous silica 
is sometimes found coating opalised silica in varying degrees of 
induration, according to its depth from the surface, presenting 
examples of opal or hydrated silica in its various stages of forma- 
tion, from gelatinous silica up to the hardest opal. The indurated 
silica is sometimes colourless, but is more frequently permeated 
with cinnabar or iron pyrites, and blackened by the tarry matter 
before alluded to. Sometimes from a diffusion of cinnabar through- 
out the mass in minute quantity, it is delicately tinted of a pinkish 
colour. The cinnabar is also found in striz, and occasionally even 
V—Sept. 6, 1893. 
