122 THE CANADIAN NATURALIST. [Dec. 



been the first to insist, was that the accumulation giving rise to 

 productive wells, occurs along the lines of anticlinal folds, where 

 the oil would naturally accumulate in fissures, or in porous strata, 

 in obedience to well-known hydrostatic laws. This view, first 

 insisted upon in a lecture published in the Montreal Gazette for 

 March, 1861, was further developed in a paper on Petroleum in 

 the Canadian Naturalist for July, 1861, and simultaneously by 

 Professor E. B. Andrews in Sillimans Journal. Since then, 

 this view, though frequently opposed, is gaining ground; and, 

 according to Prof. Andrews and Dr. Newberry, is sustained by all 

 experience in the oil fields of the United States, as it also is in 

 Canada. This remark applies to large accumulations, and to 

 flowing wells, but oil may doubtless flow slowly from horizontal 

 strata containing it. 



As to the origin of the petroleum, Dr. Hunt supposes that it is 

 indigenous in the two limestone formations already mentioned, and 

 that it may have thence risen and accumulated in overlying 

 pervious strata, or in fissures capped or sealed by impervious beds, 

 such as the Pennsylvania sand-rock, or quarternary gravel beds. 



He is inclined to think, however, that petroleum may also be 

 indigenous in certain sandstones of Devonian or Carboniferous 

 age, and referred to Lesley's observations to this effect, closely 

 agreeing with those of Wall and Cruger in Trinidad, where fossil 

 plants are sometimes found partly converted into petroleum, and 

 partly into lignite. 



Dr. Hunt regards the process by which animal and vegetable 

 hydrocarbonaceous tissues have been converted into solid or liquid 

 bitumen, as a decay or fermentation, under conditions in which 

 atmospheric oxygenation is excluded, so that the maximum amount 

 of hydrogen is retained by the carbon ; and as representing one 

 extreme of a process, the other of which is found in anthracite 

 and mineral charcoal, the two conditions being antagonistic, and 

 excluding each other, and the production of petroleum implying, 

 when complete, the disappearance of the organic tissue. Hence 

 pyro schists, the so-called bituminous shales, and coal, are not 

 found together with petroleum, but in separate formations, and it 

 is to be borne in mind that the epithet bituminous applied to the 

 former bodies is a mistaken one, since they seldom or never contain 

 any bitumen, although, like all fixed organic bodies, they yield 

 hydrocarbons by destructive distillation. The fallacy of the notion 

 which ascribes petroleum to the action of subterranean heat on 



