INTRODUCTION. 
11 
No attempt av i 11 be made to give a historical review of the theories 
advanced to account for the presence of petroleum within the earth’s 
crust. In the great Appalachian oil fields, of which these three 
quadrangles are a part, there seems to be no good reason for question¬ 
ing the conclusions of the early investigators that the great sedi¬ 
mentary deposits contained enough organic matter to constitute an 
adequate source of supply for the oil. There seems wanting, however, 
a theory that provides a logical sequence of events from the time the 
partially isolated bits of bituminous matter were entombed in the 
sedimentary deposits until they again appeared in the porous rocks 
as volatile hydrocarbon under enormous pressure. Since the operator 
is not concerned so much in this phase of the subject as he is in the 
forces and conditions which have influenced the segregation of the 
oil into pools of commercial value, the economic feature of the problem 
may be considered as beginning with the appearance of petroleum in 
the shales. 
In dealing primarily with the economic side of the subject, the 
object is to collect facts from developed oil pools and by a careful 
comparison of such data to learn how these accumulations have taken 
place. With this question determined, but half of the problem is 
solved from a practical standpoint. To make use of this knowledge 
in locating new and undeveloped oil territory, it is necessary to know 
what and how many of the governing factors which control the 
accumulation can be determined from the surface and what amount 
of information will be required from the drill before prognostication 
with reference to oil territorv can be successfullv made. The prob- 
lem therefore divides itself into two parts. First, what are the laws 
and conditions that govern the accumulations of oil? Second, are 
the geologic conditions such that from outcrops it is possible to deter¬ 
mine where the accumulations are most likely to occur? Laws of 
accumulation, once determined, are applicable to all areas of similar 
physical conditions, but the relation of the deeply buried oil-bearing 
sands to outcropping rocks may be different in even closely associated 
areas. Hence the structural relation of surface and underground 
strata must be determined separately for each area examined, but a 
knowledge of the conditions existing in a number of different areas 
may show what can reasonably be expected in an uninvestigated ter¬ 
ritory. 
