THE BEREA GRIT OIL SAND IN THE CADIZ 
QUADRANGLE, OHIO. 
By W. T. Griswold. 
IXTKODITCTIOX. 
The anticlinal theory of the accumulation of oil and gas is now 
generally accepted. Through the investigations of Edward Orton, 
I. C. White, and other geologists working in the great Appalachian 
oil Held, it has been placed on a substantial basis, and has been sub- 
jected to the supreme test of prediction. Important practical devel- 
opments, both in the extension of known fields and in the discovery 
of new productive territory, have followed its application. In a large 
part of the Appalachian oil field, however, the geologic structure 
makes it extremely difficult to determine the localities where oil and 
gas should accumulate in accordance with the theory. To an extent 
not generally realized the flexures of the strata are irregular and dis- 
continuous, and the development of one oil pool affords little, if any, 
assistance in locating others on the same or adjacent anticlines. In a 
region characterized by such irregular structures, only instrumental 
work of a high degree of refinement will serve to locate the axes of 
the flexures and the exact form of their slopes. The first essential in 
such work is an accurate topographic base map, such as has not been 
in existence for any part of this held until very recently. 
In connection with the topographic mapping of the Cadiz quadrangle, 
in eastern Ohio, an exceptionally favorable opportunity was afforded 
for working out the details of structure and subjecting the anticlinal 
theory to a rigid test. The quadrangle contains several oil pools of 
considerable productiveness, and there is reason to believe that there 
are others equally valuable, but as } T et undiscovered. The location of 
prospect wells has hitherto been determined largely by guesswork, 
and this is an extremely expensive method. The main object of the 
present report is, therefore, to afford some practical guidance to the 
driller in locating such prospect wells. As will be pointed out more 
fully later, correct location with reference to the flexures of the strata 
is only one of several conditions essential for a productive oil or gas 
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