234 QUICKSILVER DEPOSITS OF THE PACIFIC SLOPE. 



for numerous deer and other wild animals, hut neither the topographer nor 

 the geologist can contemplate these smooth, green surfaces with any sat- 

 isfaction, for the brush is often impenetrable for men or horses, while the 

 matted roots and accunudated mold seldom allow an insj ection of the 

 underhing rock. The growth of the brush seems capricicus and is not 

 altogetiier dependent on either the exposure or the soil, for often a portion 

 of a slope is densely covered with brush while the remainder is wholly free 

 from it. The distribution, however, is probably governed to a great extent 

 by the amount of moisture, for the southern exposures are much less often 

 obstructed than the northern ones. The valleys, on the other hand, are 

 usually i'ree from brush aiul, like a portion of the hills, are studded with 

 fine oaks, growing as a rule at distances of one or two hundred feet from 

 one another and often as picturescpiely disposed as if set out by a skillful 

 landscape gardener. 



This portion of California is full of mineral springs, and Clear Lake 

 possesses its share, of which the warm chalybeate rising through the waters 

 of the lake at Soda Bay is the best known and, with the charms of scener}-, 

 yearly attracts a number of visitors. Of more scientific interest are the 

 two borax lakes — pools without outlets — in which borax has concentrated 

 and accunudated to such an extent as to have yielded a large quantity of this 

 salt to conmierce. But by far the most remarkable localit}' in the region 

 is the Sulphur Baidc, where extremely hot springs and large accuiuulations 

 of native sulphur were long ago known to exist. When this sul|)hur came 

 to be exploited it was found that underlying and in part mingled with it 

 there were large quantities of cinnabar. As may be seen from Chapter I, 

 the production of quicksilver at this locality has reached a large total, 

 though it has not proved the almost inexhaustible source of supjdy it was 

 once su[)posed to be. 



Geoiogica; map — Tlic SulpluM' Bauk lics at tlic cxtrcme northwest limit of 

 the area investigated by Professor Whitney aiul his assistants, and its gen- 

 eral geological relations were so little known at tlie time when this investi- 

 gation was undertaken that it was found indispensable to a clear understand- 

 ing of the occurrence of ore to submit a district of considerable size to ex- 

 amination. Tlie oldest rocks in the neighborhood of Clear Lake belong to 



