310 ANNUAL REPORT 
v 
at such places, for all admit that such are there found. However the great 
pools of oil and gas lie near the surface where the temperature is not more 
than 60 degrees above that at the surface, allowing an increase of one de- 
gree for each 50 to 60 feet of descent. In fact important pools have been 
found at depths of 100 feet or even less, and it is apparent to all that the 
temperature at such places must be little in excess of the surface average. 
The evidence of the absence of heat in the oil or gas-bearing rocks in earl- 
ier times is as positive as the present. Heat is one of the principal factors 
in metamorphism, and if any such temperatures as the inorganic theories 
demand had existed, the rocks themselves would furnish unmistakable 
evidence. In Ohio alone probably 50,000 wells have been sunk to depths 
approximating 1,000 feet ; many have reached 1,500 feet ; a smaller number 
2,500 feet, and occasionally a well has exceeded 3,000 feet. Now the drill- 
ings from these are a unit in denying any evidence of high temperatures. 
In fact fragments brought up from the greatest depths show no more 
evidence of heat than do those 100 feet or less below the surface. 
From these lines of testimony it is safe to say that the rocks which now 
contain the oil and gas have never been highly heated. There remains but 
one alternative for the advocates of this class of theories, and that is oil 
and gas were produced at great depths and have gradually risen from that 
place to the position which they now occupy. To this there appears to the 
geologist an insuperable difficulty, for lying between these deep seated 
and hence highly heated rocks and those which now contain oil and gas 
are, in many places at least, great thicknesses of compact shales and other 
fine grained rocks which are impervious. This is well illustrated in south- 
eastern Ohio where the Berea grit, and of course the rocks lying above it, 
and which contain important quantities of oil or gas have lying below 
them a great mass of fine grained shales. At Lancaster their thickness _ 
is 805 feet; at Junction City 1,174, at McConnelsville 1,739 and at the Ohio 
river probably 3,000 feet. Ii the oil and gas could have risen from below, 
passing through this great depth of shales, they would have continued 
their ascent and been wasted at the surface long before man appeared. 
This specific example can be duplicated in some form in every great oil or 
gas field. Fortunately parts of the geological scale are impervious, for 
otherwise oil or gas in large quantities could not exist. 
If the inorganic or chemical theory were true it would be reasonable 
to expect petroleum and natural gas in igneous rocks since they have been 
highly heated, and hence in a condition favorable for the production of | 
these fuels. Experience, however, has shown that neither oil nor gas is 
found in rocks of this kind. So far as the writer knows there is no excep- 
tion to this statement. 
