STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 71 
of wind-blown sand were formed also, and their formation is con¬ 
tinuing at present. During the late Quaternary the deposits and 
topographic forms resulting from all these processes have been carved 
by erosion; wide areas have been denuded of the thin Pleistocene 
capping; and in many places bits of terrace deposits are left merely 
as scattering remnants. 
STRUCTURE AND CONDITIONS AFFECTING TIIE PRES¬ 
ENCE OF OIE. 
THE ANTICLINAL THEORY. 
The anticlinal theory of oil accumulation assumes that the oil, 
being of lesser gravity, rises above the water present in porous 
rocks and collects at the highest possible points in upward folds, 
being there confined by impervious strata arching over the folds. 
The presence of water, according to this theory, is considered as 
fundamentally necessary for the carrying out of the process of 
accumulation in anticlines. 
The presence of oil in anticlinal folds was repeatedly observed in 
the eastern part of North America during the latter half of the 
nineteenth century. E. B. Andrews noted its occurrence along low 
anticlines in West Virginia and Ohio as early as 1861, and described 
this occurrence that same year,® and again, with more assurance of 
its wide application, in 1866. 6 
In 1863 the Canadian geologists, c in describing the oil springs 
immediately north of Lake Erie, noted their close relation to the 
anticlinal structure, and formulated the theory that the rise of the 
oil is due to the presence of water in the rocks. Their brief state¬ 
ment is as follows: 
Some of these springs appear to be on the line of the.great anticlinal which runs 
through the western peninsula, and subordinate undulations of a similar character 
will be found connected with others. The oil, being lighter than water and per¬ 
meating with it the strata, naturally runs to the highest part, which is the crown of 
the anticlinal, whence it escapes to the surface by some of those breaks which are 
usually found in such positions. 
Also in 1863 Sterry Hunt, to whom the above-cited conclusions in 
the Canadian report are probably due, described the oil of western 
Ontario as derived from low anticlines/ 
The following quotation is from an account written in 1885 by 
I. C. White* of his search for some method of determining the loca¬ 
tion of gas accumulations: 
In the prosecution of this work I was aided by a suggestion from Mr. William A. 
Earsenian, of Allegheny, Pa., an oil operator of many years’ experience, who had 
« Am. Jour. Sci., 2d ser., vol. 32, July, 1861, pp. 85-93. 
i> Am. Jour. Sci., 2d ser., vol. 42, July 1866, pp. 33-37. 
c Geology of Canada, Canadian Geol. Survey, 1863, p. 379. 
d Ain. Jour. Sci., 2d ser., vol. 35, March, 1863, pp. 169-170. 
« Science, vol. 5, No. 125, June 26,1885. 
