42 E. B. Andrews on Petroleum in its Geological Relations. 
In favor of the other theory, that petroleum, as now generally 
found, is the product of a distillation of bituminous shales, &c., 
as suggested by Dr. Newberry and others, the following argu- 
ments may be urged: Ist. Oil may be artificially produced by 
distilling such shales and other bituminous materials. In all 
essential respects, the analogy between the natural and artificial 
oils is complete. 2d. The phenomena of oil and gas exhibited 
in our oil fields greatly resemble those observed in the artificial 
distillation of oil from bituminous materials, These phenomena 
include inflammable gases, naphthas, heavy oils, asphaltums, &c. 
3d. It is believed that some petroleum has been actually pro- 
duced in the earth by distillation. Dr. Newberry, in an article 
on ‘“ Rock Oils of Ohio,’’ thinks he finds local proof of the dis- 
tillation of the petroleum in the great bituminous springs of 
California, from Tertiary lignites, there being evidences of recent 
igneous action in the region. European geologists have attrib- 
uted a similar origin to the petroleums of Italy. Of course, 
where igneous action is intense, all the bitumen would be en- 
tirely driven off. The same would be true where the action is 
considerable and long continued, as in the anthracite coal region 
of Pennsylvania where the coal has lost its bitumen, but no oil 
was formed, or, if formed, it was soon dissipated in gas. 4th. 
There is an abundance of oil-making material in the earth. 
The subterranean retort is largely charged. 5th. A compara- 
tively low temperature is believed to be adequate to set free the 
oil vapors. 6th. By this theory there might be produced an 
almost indefinite quantity of petroleum, since bituminous strata 
are found widely distributed. In this way the existence of pe- 
troleum in so many different geographical districts may be 
readily explained; whereas, by the opposing theory, we are not 
certain that petroleum, as such, has been produced by the direct 
bituminization of organic matter, except. in few strata and in 
very insignificant quantity. Finally, the agency whigh would 
volatilize the liquid bitumen, or petroleum formed by direct 
bituminization, and bring it up and distribute it through the 
_ oil horizons would certainly be adequate to distill the 
ituminous shales, &c., and bring up the oil to the same ele- 
vations. 
It may, however, be objected, that if this theory of distilla- 
at m: 
The question, then, would be reduced to this, viz: do the bor- 
ings in deep wells ever show that the deep bituminous strata 
have lost any of their original and normal quantity of bitumen? 
ee 
P ee 
