PETROLEUM AND NATURAL GAS IN NEW YORK 415 



products of the gas retort. The production of gas and petroleum 

 in connection with volcanic agencies is of frequent occurrence 

 and does not excite our wonder. It is easily explained in accord- 

 ance with the principles above noted. In such cases the strata 

 that are traversed by molten rock show the effect of the unusual 

 heat to which they have been subjected by unmistakable trans- 

 formations. 



There seems therefore no reason to doubt that destructive 

 distillation gives origin to some occurrences of the substances 

 whose origin we are considering. But there are several strenu- 

 ously urged and widely accepted theories that put this agency 

 in the front rank and in reality make it the great source of 

 petroleum. Two of these theories may be named in this con- 

 nection: those, namely, of the late Dr J. S. Newberry and of 

 Prof. S. F. Peckham. 



Newberry's theory was the first to be fully and elaborately 

 stated and was propounded at the right time, viz, just when 

 petroleum was coming to its first full recognition. It seemed 

 to match well with many familiar facts of observation and was 

 accordingly received with something like enthusiasm, as giving 

 an intelligible and rational answer to questions that everyone 

 was asking. 



It was first published in a paper on the rock oils of Ohio in 

 the Ohio agricultural report for 1859. He says: " The precise 

 process by which petroleum is evolved from carbonaceous matter 

 contained in the rocks which furnish it is not yet fully known, 

 because we can not in ordinary circumstances inspect it. We 

 may fairly infer, however, that it is a distillation, but generally 

 performed at a low temperature." Again he says: " The origin 

 of these two hydrocarbons (petroleum and gas) is the same, and 

 they are evolved simultaneously by the spontaneous distillation 

 of carbonaceous rocks." [Geology of Ohio, 1: 192] 



In Dr Newberry's view the great black shale of Ohio 

 (Hamilton, Portage, Chemung) is the main source of the petro- 

 leum of the oil fields of western Pennsylvania, New York and 

 eastern Ohio, which these shales underlie. 



Prof. S. F. Peckham has furnished another statement of the 

 distillation theory but has recognized the necessity of higher 

 than normal temperature and has added a source of heat to 



