96 EK. ORTON—GEOLOGICAL PROBABILITIES AS TO PETROLEUM. 
Now, if the rock cover of a gas field is to any extent permeable, it would 
certainly seem that a pressure of over 200,000 pounds to the square foot, — 
for this is what 1,500 pounds to the square inch means, ought to be able 
to find the open way. Any rock which withstands such a pressure for 
thousands and millions of years might as well be labeled ‘‘ no thorough- 
fare.” Similar reasoning will apply to pressures of one-half, one-fourth, 
or even one-tenth of the 1,500 pounds which was registered in the 
Monroe well. 
If it had been possible for this imprisoned gas to escape at any meas- 
urable rate with a pressure of 1,500 pounds to the square inch, then the 
present figures must indicate a remainder of pressure after thousands and 
millions of years of waste. If the gas has ever escaped it should be es- 
caping now. If itis now escaping, the pressure must be steadily falling 
unless the supply is being constantly replenished ; but there is no source 
of supply except by the destructive distillation of the organic matter of 
the rock, and there could be but the feeblest possible supply from this 
source. The underlying rocks show no indications of having been sub- 
jected to the process of destructive distillation or to any unusual degree 
of heat. In fact, they distinctly negative such a supposition. In the 
case of the Monroe well, the 2,300 feet of overlying rock included sey- 
eral sandstones which could well enough become gas rocks if there were 
any source of gas at hand. In fact, these very strata are found to be 
important gas rocks in numerous instances in this immediate region. 
In the Monroe well, however, while the sandstones were normal, as re- 
spects thickness and grain, all of them were found wanting in gas to an 
unusual degree. In other words, while the reservoirs were present they 
were practically empty, and yet a great volume of gas under a tremen- 
dous pressure lay securely stored. only a few hundred feet below them. 
Not a sign of the presence of this gas had ever escaped through the thick 
cover already noted, and probably no one would claim that oil would 
pass through strata impervious to gas. These facts, I submit, do not 
seem consistent with any freedom of ascent of the bituminous series 
from stratum to stratum. I accordingly repeat the proposition with 
which I set out, namely, that it is probable that neither petroleum nor 
the gas derived from it can rise through the impervious rocks that cover 
them. In other words, by impervious we mean impervious. 
STRUCTURE OR ARRANGEMENT OF STRATA THE DOMINANT FEATURE IN 
ACCUMULATION OF GAS OR OIL 
It is probable that in all accumulations of oil and gas the structure or 
arrangement of the strata involved is the dominant feature. This conclusion | 
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