154 



F, Shepherd on the Phiton Geysers of California. 



miles from the present tide, I discovered a belt of remarkably 



in some places by metamorphic action^ 



*^ 



hard and heavy limestone; evidently fossiliferous and yet changed 



In breaking into this 

 bed of limestone, however, I was surprised lO find imbedded 

 in the solid rock, sharks teeth as perfect in their serrated edges 

 as those of present living species swimming in the bay only two 

 miles distant. I examined the range of hills eastward about 

 one mile, which bounds and divides Napa valley from Suisun, 

 and there I found the rocks to be a porphyry, with numerous 

 springs flowing out at the base. I applied my thermometer and 

 was surprised to find no two springs of the same temperattire, 

 they ranging from seventy-eight degrees Fahrenheit downward. 



I now travelled about thirty miles northward in Napa valley, 

 following the above mentioned chain of hills to the thermal 

 springs of Messrs. Ritchie and Tucker, where I found the tem- 

 perature of different springs as foUotvs : 



■ No. 1, 105 degrees, Fah. 



2, 120 



3, 144 



4, 133 



5, 147 



6, 144 



7, 129 



8, 124 



9, 120 

 10, 131 



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No. 



132 degrees, Fah. 



12, 169 



13, 129 



14, 150 



15, 131 



16, 128 



17, 93 



18, 100 



19, 120 



20, 118 



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These springs are all embraced in a half mile square of level 

 bottom land near the base of a small hill or mound of conglome- 



rate rock about one hundred and fifty feet in height. 



There is httle 



The same 



kind of rock also extends underneath the springs. 

 or no opportunity for surface cold water to commingle with 

 them, and it is a remarkable fact that they are continually chang- 

 ing their temperature, so that one that is now moderately warm 

 will in the space of a few weeks or months become hot beyond 

 endurance. - This shifting of the internal heat greatly excited my 

 curiosity, and on enquiring, I learned from Mr. Cyrus that the 

 Indians had pointed out a place near the foot of Mount St. Helena 

 where the hot waters formerly flowed, but had now ceased. I 

 believed this to be a good opportunity to test the truth of their 

 tradition, and repaired to the spot. Externally there was no un- 

 common appearance to designate, thfe locality.' Neither a surplus 

 nor scarcity of vegetation, and no appearance of scoria, tufa or 

 travertine, as might have been expected. I found one place, 

 however, slightly warm on the surface, which on excavating (o 

 the depth of two feet became so hot that I could not bear my 

 hand in the mud and clay. I inserted the bulb of my thermome- 



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