_ FEATURES DOMINATING PETROLEUM ACCUMULATION. 97 
is clearly a probability of the first order. A dozen years ago there were 
a few voices raised against certain applications of this doctrine, but at 
the present time I know of no opposition whatever to it. It harmonizes 
so well with the teachings of physics and its applications are so obvious 
and convincing that reasonable men cannot easily find standing place 
for an attack upon it. 
I will not weary you with a repetition of the thrice-told tale of anti- 
cline, syncline, and monocline, but will only add that the controlling 
influence of structure comes out more and more clearly as the oil and 
gas fields of the world are adequately studied. The latest confirmation 
comes from Burma. Dr Fritz Noettling’s excellent work on the Geo- 
logical Survey of India, brought down to 1895, fully establishes the fact 
that the oil fields of the Irawaddy, famous for more than a century, con- 
form in all particulars to the laws of structure that have been worked 
out more fully than elsewhere in the great oil fields of the United States. 
He shows, what we might have been ready to accept without demonstra- 
tion, that anticlines and domes of Miocene sandstone exert the same in- 
fluence in the accumulation of gas and oil that like features exert in the 
Devonian sandstones of Pennsylvania or the Ordovician lmestones of 
Ohio. 
EQUALITY OF PRESSURE ON THE CONTAINED LiIquips AND GASES 
In the sixth place, and finally, it is geologically probable that in the 
fields where salt water rises from deeply buried porous rocks under artesian 
pressure the same pressure will be exerted on the gas and oil which with the salt 
water, are the joint tenents of the rock. In other words, the rock pressure 
of gas wells in certain districts is due to the salt water that follows the 
gas, and it can be measured by the height to which this water rises above 
the gas reservoir. In my judgment this probability, when duly quali- 
fied, also belongs with the few that are of the first order. The facts de- 
rived from the gas fields of Ohio and Indiana seem to me to constitute 
a demonstration of this claim, but as several well known geologists, 
especially interested in petroleum, have emphatically dissented from this 
view, we are not warranted in claiming more for it, to say the least, than 
for the conclusions which have been previously stated. 
_ The theory referred to was from the first restricted in its application 
to districts in which the water found in the porous rock with the gas and 
oil rose under unmistakable artesian pressure and to the same height 
throughout the field. Shale gas was from the first distinctly recognized 
as demanding a different explanation of its pressure. 
In regard to the salt-water fields, there is probably but one date in 
