THE ALKALINE AND BOEACIC LAKES OF CALIFORNIA. 161 
live miles long, by about seven wide, surrounded by mountains, 
which in many places rise abruptly from the water’s edge. 
Boat-life on this lake is delightful ; the water is smooth, there 
is usually a sufficient breeze for sailing, and should it fall calm, 
an Indian can always be hired to row. 
Lying about a mile beyond the ridge which borders Borax 
Lake on the north-east, and at the foot of a shorter arm of Clear 
Lake, which extends off to the southward parallel with the 
larger one, is an interesting locality, known as the “ Sulphur 
Bank.” It is some six or seven acres in extent, and consists of 
■a much decomposed volcanic rock traversed by innumerable 
fissures, which has become almost covered by a large accumula- 
tion of sulphur. 
From the fissures steam and gas are constantly issuing, and 
•over and through the mass large quantities of sulphur have been 
deposited in such a way that at a short distance the whole bank 
appears to consist of this substance. Into some of these cavities 
a pole may be inserted for a distance of several feet, and they 
are often lined with stalactites and beautiful crystallizations of 
-sulphur. 
Sulphur is being constantly deposited, and its deposition is 
attended by the evolution of carbonic and boric acids. The 
gaseous matters issuing from these crevices appear to be the 
agency by which the various substances now deposited in the 
cavities have been brought to the surface. Sulphur is deposited 
on the sides of the various fissures either in the form of crystals, 
or as amorphous translucent masses of a beautiful yellow colour. 
It is sometimes intermixed with cinnabar, the presence of which 
was first discovered by Dr. Oxland ; but more frequently with 
minute cubical crystals of iron pyrites. Pulverulent silica, black- 
ened by some hydrocarbon resembling coal-tar, is also frequently 
•observed. 
On the sides of the cavities colloid silica is found coating 
chalcedony and opalescent quartz in the various stages of form- 
ation, from the gelatinous state to that of the hardest opal. 
The indurated material is sometimes colourless, but is more 
frequently permeated by cinnabar and iron pyrites, or blackened 
by the tarry matter before referred to. Cinnabar is also found 
in laminae, and occasionally even in veins and concretionary 
masses of considerable thickness. 
In addition to being employed as a source of sulphur, this 
deposit has been worked for quicksilver, and has produced 
large quantities of that valuable metal. 
On the shore of Clear Lake, near the sulphur bank, is a hot 
spring, of which the outlets, even when the water is low, are 
partially beneath the lake, so that the amount flowing from it 
cannot be ascertained. Hot water, however, rises through the 
