The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1882-08-18
WHAT PETROLEUM is.
various Theories nj sts Origin Where
the ou Comes FrOm-rhe Probable
supply.

supply
The casual visitor to the Pennsyl-
vania oil region, as he views the greasy
huid gushing from its rich reservoirs.
two Thousand feet below the surface.
hnds himself involuntarily asking the
primal question, Where does it come
from, and how and where was il formed
A puzzling question. surely, and, if pro-
pounded to any competent and thorough
geologist, would only elicit a shake OF
the head, and the brief reply that he
didn't know. But however careful the
scientific man may be about advancing
a theory that the discoveries of to-
morrow may knock higher than a kite,
the average Yankee never allows a con-
undrum OF this kind to be propounded
to him without making one or more
attempts at guessing it. The difficult
question of the origin of petroleum has
not seemed to his prolific mind too big
to be grappled with, and at present two
popular theories exist in regard to this
interesting subject, each of which has
Its strenuous advocates.
The first of these theories holds that
the rock in which the oil is now found
Is the parent rock in which it originated.
The Pennsylvania oil rocks are series
OF sand rocks of varying thickness, scat
tered somewhat irregularly over the
northwestern part of the State, and pro-
life In oil at depths below the surface
varying from 500 feet to 1000 feet Orig
inally they were deposited by the action
OF water, either as long stretches of sea-
beach or immense sand bars formed by
eddying and whirling currents. The ad-
vocates of the parent-rock theory main
tain that along with this sand was de-
posted organic vegetable or animal
matter, which. by the chemical action of
the succeeding ages, has been trans
formed into oil and gas, and kept stored
In these Theoretically sealed reservoirs
until the searching drill Of the enter
prising oil-operator should penetrate its
hidden chambers and bring it forth to
light an inquiring and busy world.
In confirmation of this theory its adj
vocates point to the coal deposits, which
are now generally conceded to have
originated from vast deposit of vegeta-
BILE matter which grew and decomposed
for ages, and then, by the combined ac-
ton of heat and enormous pressure,
were packed away in solid masses to
provide the future fuel of the world.
A chemical analysis of the two articles,
coal and petroleum, discloses the fact
that they contain nearly the same ele-
mental ingredients, in slightly different
proportions, perhaps, but practically
the same, the only real difference con-
sisting in the fact that one is now a
solid and the other a fluid. AS the oil
Is found at a distance of from ], ZOO to
1000 feet below the prolific coal meas
ures, and if deposited along with the
sand rock in which it is now found, must
be many ages older than the coal de-
posits, it is argued that the immensely
longer period since its original deposit,
and the higher temperature to which it
is subjected by its greater depth below
the surface, may easily account for the
chemical action necessary to make it a
fluid instead of a solid, as in the case of
coal.
The second and more generally &C
cepted theory is that the petroleum is
formed by the constant distillation of
gas from the underlying carbonaceous
shales of the silurian period, which in
the Pennsylvania oil region are sup
posed to lie at a sufficient depth to be
subjected to high temperature and to
be constantly generating gases. If this
theory is accepted, the conditions neces-
sary for the formation of petroleum de-
posits are three-fold First, geologi-
cal horizon deep enough below the sur
face to generate gases by the operations
of internal heat second, horizon of
proper temperature for the purposes
of condensation, and third, reservoir
for storing the condensed petroleum.
The advocates of this theory claim that
these lower shales lie at the proper
depth to fill the first of these conditions,
and that the gas thus generated, being
very light and of a peculiarly-penetrat-
ing nature, arises through the crevices
and assures of the everything rocks until
it reaches the horizon of condensation,
which they claim. according to develop
ments made by the drill, varies in dis
lance from 500 to 1900 feet below the
surface. The third condition is filled,
according to this theory, by these sand
rocks, which, lying within the horizon
of condensation and being of porous
nature, hold the condensed petroleum
as a sponge holds water. These rocks
are Theoretically sealed at the top by an
impervious shell, which prevents the
lighter por tons of the oil and gas from
escaping to the surface until this shell
is penetrated by the oil-operator's drill,
when it rushes forth with astonishing
force. If this theory is correct, then in
all probability the process of formation
is constantly in operation, though pro-
ceeding at very slow rate, the immense
deposits lately discovered being the
slow accretion of unto ages.
The advocates of this theory fortify
themselves by the statement that the
series of Devonian rocks in which the
oil deposits are now found extend over
great deal of territory in which the
drill fails to find oil, and that if the
theory of original deposit of the petro-
leum- producing matter along with these
same deposits were true then the oil
should be found wherever the rock is
found. On the contrary, they claim the
rock may exist where there are no under
lying shales TO produce the petroleum
gases, or the everything strata may be
upheaved to such an extent that the
gases may escape to the surface through
vertical assures and thus mingle with
the atmosphere and be lost. In proof
- Al r. Il A