100 PETROLEUM AXD NATURAL GAS. 



[Feb. 5, 



2. Those bitumens that do not form asphaltum and contain par- 

 affine. 



3. Those bitumens that form asphaltum and contain paraffine. 



4. Solid bitumens that were originally solid when cold or at 

 ordinary temperatures. 



'* The first class includes the bitumens of California and Texas, 

 doubtless indigenous in the shales from which they issue. The 

 exceedingly unstable character of these petroleums, considered in 

 connection with the amount of nitrogen that they contain and 

 the vast accumulation of animal remains in the strata from which 

 they issue, together with the fact that the fresh oil soon becomes 

 filled with the larvae of insects to such an extent that pools of 

 petroleum become pools of maggots, all lend support to the theory 

 that the oils are of animal origin. 



''The second class of petroleums include those of New York,. 

 Pennsylvania, Ohio and West Virginia. These oils are undoubtedly 

 distillates and of vegetable origin. The proof of the statement 

 seems overwhelming." 



Leaving the question of origin for the present with this rapid 

 survey of the views of the more prominent writers on the subject, 

 and reserving for the end of this paper the mention of some few 

 experimental results of my own which bear on it, I will briefly 

 allude to the other question of the conditions of formation of the 

 bitumen or petroleum. Here of course we practically leave the 

 theories of inorganic origin to one side and assume that its source 

 is organic. Was it formed where it is now found in situ or is it a 

 distillate from lower-lying formations ? 



As already stated, Sterry Hunt believed that the fossiliferous lime- 

 stones were the source of the Canadian oil, and he also strenuously 

 insisted that they were formed in this same formation and did not 

 come into it from an outside source. This view of the production 

 of the petroleum i?i situ is also in the main supported by Profs. 

 Lesley and Orton, although both seem to admit that under some 

 circumstances a modified distillation takes place. The latter says : 

 *' Different fields have different sources. We can accept without 

 inconsistency the adventitious origin of the oil in Pennsylvania 

 sandstones and its indigenous origin in the shales of California or ia 

 the limestones of Canada, Kentucky or Ohio." On the other hand,. 

 Profs. Newberry and Peckham have advocated the theory that the 

 oils of New York, Pennsylvania, West Virginia and Ohio at least 



