The Powder River County examiner and the Broadus independent., 1920-07-09
FORMATION Of THE
OIL AND GAS DoMts
GEOLOGIST GIVES INTERESTING
ACCOUNT OF FORMATION OF
GAS AND OIL DONIES

Oil and gas are probably the re-
suit of the distillation under enor-
nous pressure of the remains of fish.
shell fish and other water creatures,
says Geologist Thomas Edwin Smith,
in the Melstone Messenger last week.
AS these creatures died their re-
mains fell to the bottom Of the sea
and mingled with the mud that was
being continually deposited. This
process continuing for ages, possibly
several hundred thousand years, re-
suited in the formation Of a shale
bed of great thickness filled with
remains that in time decayed and
produced gas or oil.
Following the shale deposits the
sea receded and sand of the shore
was deposited on top of the shale
beds forming in time great thickness
of sandstone. Following this another
lowering OF the surface brought the
sea back and produced another bed
OF shale to be in turn covered with
more sandstone possibly containing
coal beds.
Oil and gas fields almost without
exception are formed as thus de-
scribed with this exception, east of
the Mississippi river bed OF lime
stone may take the place of or be
included in the shale or sandstone.
The oil deposits fthe western part
OF America, say Wyoming. Montana
and Alberta, had their origin in sim
liar events if not indeed the same
event.
Very late in the earth's history,
just after the Bull mountain coal
fields We're laid down great pressure
developed to the southwest that re-
suited in forcing the Rocky noun
tains up to level considerably higher
than they are now. This movement
was manifested east of the Rockies
by wrinkling and folding Of the
strata.
II you will lay sheet Of paper
flat On a table, then put your fingers
on each side and push them together
you will cause the paper to wrinkle
and buckle in various shapes proba-
bly, in one long fold lengthwise of the
sheet. possibly in several little folds
in different directions. That on Il
small scale represents what happen
ed on a large scale when the pres
sure from west Of the Rockies push
ed northeastward against the edges
OF the great fiat sheet of shales and
sandstone which make up the foot
hills and prairies. The Judith noun
tains. Black Butte, the Cat creek an
ticline and the Porcupine dome are
some OF the wrinkles as produced.
When other conditions are fulfilled
these wrinkles may become reser-
voirs for Oil and gas. 1t comes in
this way. The rocks deep down in
the earth's crust are full of water.
Oil being lighter floats on the wa
ter. and the enormous pressure on
the water forces the liquids upward.
This causes the Oil to flow through
the porous sand or sandstone to the
higher points in the anticlines and
DANES. II now there is a layer of
hard, close shale over the porous
sandstone, we will have a large body
OF gas and Oil in the dome or anti
cline under enormous pressure. II
this shale isiacking. or if there is a
crack through it the oil will seep to
the surface and eyaporate. Ii hole
be drilled through the impervious
shale cover into the sandstone the
oil or gas will flow into and up that
hole sometimes spouting far into the
air as gusher.
Since certain underground condi-
tions must prevail in order that an
Oil field may occur it is the business
OF geologist to discover such a
structure from study of the surface
indications. The best any geolosist
can do is to indicate that there is a
structure that may contain a reser-
voir of gas or Oil and nothing but
the drill can decide whether there is
a commercial quantity Of oil or not.
BY THOSE 6