298 ANNUAL OF SCIENTIFIC DISCOVERY. 



ured vertically in the geological scale, and geographically from Nova 

 Scotia to Lake St Clair, and from Virginia to Tennessee River. The 

 geographical area, covered by the oil-bearing group of rocks in the 

 United States, Canada, New Brunswick, and Nova Scotia, cannot be less 

 than 200,000 square miles. 



Over this area, wherever oil and gas springs are found, there we may 

 reasonably hope for success in boring deeply for oil. But oil and gas 

 springs are not always sure indications of subterraneous supplies of oil 

 in their immediate vicinity, for the course the fluids may have pursued 

 from deep depths to the surface may have been very tortuous. Neither 

 is the absence of such springs absolute negative proof of oleaginous accu- 

 mulations beneath, for in many very notable instances, such as the lower 

 portion of Oil Creek, and at Smith's Ferry, on the Ohio River, very 

 copious fountains were struck where no surf ice signs were visible. 



I deduce the following practical and economical conclusions : First, 

 Each widely-separated locality must be governed by its own 1 >\vs as 

 developed by boring and observation. Second, Each geological horizon 

 or stratum of oil-bearing rock received its supply, not from another, but. 

 from causes operating at the time of its own deposition. Third, There is 

 not now any reproduction of oil, but we are drawing from fountains filled of 

 old. Fourth, No stratum of rock is so thoroughly saturated with oil as 



c* 



to form a subterranean sheet or belt of rocks where petroleum is surely 

 to be found, but in frequently isolated cavities, or fissures, at various 

 depths and of various sixes, and containing diverse grades of oils. 



THE GEOLOGY OF CALIFORNIA. 



From communications made to Silliwaii's Journal by Prof. J. D. 

 Whitney, we derive the following summary of facts developed in the 

 geological survey of California: 



In the mountains of the Sierra Nevada, abundant proofs have been 

 obtainedrespectingthe former existence of glaciers of great magnitude. 

 Thousands of acres of granite retain the most exquisite glacial polish, 

 and the existence of lateral, medial, and terminal moraines is as 

 easily observed as in the Alps at the present day. 



Perhaps the most striking result of the survey is the proof of the 

 immense development, on the Pacific side of our continent, of rocks 

 equivalent in age to the Upper Trias of the Alps. It is believed that 

 this formation extends from Mexico to British Columbia : occupying a 

 vast area, although much broken up, interrupted and covered by vol- 

 canic and eruptive, rocks, and usually much metamorphosed. 



Accompanying this Triassie formation in the Sierra Nevada is an 

 extensive development of Jurassic rocks. Enough, however, have 

 been found to justify the assertion that the sedimentary portion of 

 the great metalliferous belt of the Pacific coast of North America is 

 chiefly made up of rocks of Jurassic and Triassie age, with a compar- 

 atively small development of carboniferous limestone, and that these 

 two formations are so folded together, broken up, and metamorphosed 

 in the great chain of the Sierra Nevada, that it will be an immense 

 labor, if indeed possible at all, to unravel its detailed structure. 

 While we are fully justified in saying that a large portion of lite aurif- 

 erous rocks of California consist of metamorphic TriassicandJuras^ 

 sic strata, we have not a particle of evidence to uphold the theory 



