320 THE PETROLEUM SPRINGS OF WESTERN CANADA. 
interesting section of highly bituminous and argillaceous slates, which 
also occur in outlying patches throughout the oil-producing region, 
and have been ascertained to belong to the lowest measures of the 
Chemung Group, the next higher in the series.* It would appear 
at first sight most obvious and natural to attribute the origin and 
source of the petroleum to the subterranean distillation of these shales, 
which contain an amount of carbonaceous matter, abundantly adequate 
for its production; but there is most unequivocal evidence to prove 
that the oil and gas come from a lower source, and are in all proba- 
bility the cause rather than the result of the bituminous nature of the 
shales.} 
Tt is a peculiar and unique feature in the Canadian rocks of Silurian 
and Devonian age, that beds impregnated with bitumen, and evolutions 
of gaseous and fluid hydrocarbons occur at various points from the 
base to the summit of the series, although nowhere to such an extent 
as in the region now under review; and the fact that these oils have 
been obtained from the Hudson River group of rocks, in which few or 
no vegetable remains occur, would lead to the inference that the oils 
and gases may be entirely of animal origin. The upper beds of the 
Corniferous limestone in Canada, and the entire mass of the Hamil- 
ton shales, are characterized by the extraordinary profusion of or- 
ganic remains, for the most part animal, with which they are charged ; 
and the evidences which they furnish of the mode of their deposition 
indicate conditions highly favorable to the conversion of the organic 
matter into substances of a bituminous nature. 
The process of bituminization consists of a species of fermentation or 
combustion, usually thought to be peculiar to vegetable matter, placed 
in such situations as not only to exclude the external air and secure 
the presence of moisture, but to prevent the escape of the volatile 
principles. The ultimate elements, and even to a great extent, the 
proximate structure of animal and vegetable tissues, are identical; and 
it is susceptible of demonstration that animal muscle, placed in 
similar circumstances, may be converted into substances closely re- 
sembling the products of vegetable bituminization. 
* A fuil account of this highly interesting section of rocks will be found in the Geological 
Survey Reports of Progress for 1847-48, and 1853. 
+ This circumstance affords a strong corroboration of the theory which has been recently 
propounded before the Freuch Academy by M, Riviere, attributing the origin of bituminous 
schists and shales in general to impregnation of their argillaceous material with carburetted. 
hydrogen. See Wells’ Annual of Scientific Discovery for 1860. 
