232 CALIFORNIA ALKALINE AND BOBACIC LAKES. 



consists of a much-decomposed volcanic rock traversed by innumerable 

 fissures, which has become almost covered by a large accumulation 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 sub- 

 stance. 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 crys- 

 tallizations 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 sub- 

 stances 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 color. 

 It is sometimes intermixed with cinnabar, the presence of which was first 

 discovered by Dr. Oxland; but more frequently with minute cubical crys- 

 tals of iron pyrites. Pulverulent silica, blackened 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 formation, from the gelatinous 

 state to that of the hardest opal. The indurated material is sometimes col- 

 orless, but is more frequently permeated by cinnabar and iron pyrites, or 

 blackened by the tarry matter before referred to. Cinnabar is also found 

 inlaminas, and occasionally even in veins and concretionary masses of con- 

 siderable thickness. 



In addition to being employed as a source of sulphur, this deposit lias 

 been worked for quicksilver, and has produced large quantities of that val- 

 uable 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 sand at various points extending over a consid- 

 erable area. A specimen of water collected by Mr. Moore from this spring 

 was found by him to contain 184.62 grains of common salt, 76.96 grains of 

 bicarbonate of sodium, 36.37 grains of free carbonic anhydride, 103.29 grains 

 of borax, and 107.76 grains of bicarbonate of ammonium, in an imperial 

 gallon ; besides silica, alumina, and traces of various other substances. 



Prof Whitney remarks with regard to this spring: "The most extraor- 

 dinary feature in the above analysis is the very large amount of ammoniacal 

 salts shown to be present in this water, in this respect exceeding any natural 

 spring water which has ever been analyzed. Mr. Moore thinks that, as in 

 the case of the boracic-acid waters of Tuscany, ammoniacal salt may be 

 separated and made available for economical purposes. This locality is 



