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THE GEYSERS OF CALIFORNIA. 839 
the northern Coast Range of the State. Two belts of 
eruptive rock have been observed in this part of the 
State, one lying thirty miles south, and the other found 
between the Geysers and Borax Lake, twenty or more 
miles away. Both are on the line of former voleanic 
activity, and near both we find many thermal springs. 
Besides hot springs, incrustations of sublimed sul- 
phur, pumice, and the light lavas are regarded as traces 
of volcanic action. These are found in many places in 
California, and in Nevada. The writer has observed 
these indications near the summit of the extinct volcano, 
Shasta.. In all cases they point to former igneous activ- 
ity. Therefore, the steam-springs and the Solfataras may 
be considered, for all practical purposes, as the poor re- 
lations of volcanoes in reduced circumstances. Such are 
the Geysers. 
Upon the 28th of May there had been a slight fall of 
rain. The morning of the 30th was quite cloudy, the 
thermometer ranging at eight o’clock from 60° to 62° 
Fahr. The temperature of the water in Pluton River, 
immediately above the confluence of the stream from the 
Devil’s Cañon varied from 65° to 70°. At the mouth of 
the cañon the temperature of the water was 90°, and 
upon walking up the bank of the stream the different 
temperatures of 95°, 97°, and 100°, were noticed. A 
light vapor was rising from the surface of the water. 
The first spring where ebullition was observed had a 
temperature of 135°. There was a free escape of sul- 
phydric acid from the cloudy water, and here the hot, 
stifling moisture began to make the walk one of discom- 
fort, ‘Upon the right hand several small springs of 190°, 
all giving off sulphydric acid, were boiling violently, and 
at the edge of a queer miniature cave on the same side, 
