Yerington times. [volume] (Yerington, Nev.) 1907-1932, 1919-10-25

to other sedimentary rocks, It IS ne
cessary for the reader to consider,
briefly an outline of the chart Of Sc
quence Of such rocks of the earth.
The lowest and geologicalIy Oldest
rocks Of our globe which are acces-!!
sible are termed .Archaen or Eozoic,
meaning without life. Above this
series, the sedimentary formations
which carry organic remains are di-l
yided into Eras which,. commencing
with the lowest are termed Paleozoic,
Mesozoic and Cenozoic,-meaning,
oldest life, middle life and recent life.
The E.ras are divided into Periods
Which for the Paleozoric Era are the
Cambrian, Lower Silurian. Upper ST.
lurian, Devonian and Carboniferous
Periods: for the Mesozoic Era, the
Triassic, Jurassic and Cretaceous
Periods; and for the Ccnozoic Era,
theTertiary and Quaternary Periods.
These Periods are further divided
into Epochs, such as Eocene, Milo
Gene and Pliocene for the Tertiary
Period; and Glacial, Champlain and
Recent for the Quaternary Period.
We will consider but few Of these
Periods and Epochs.
Coal was first found III Pennsylvania
In the Carboniferous Period whence
the name. Oil in the same general
territory was found iii formation geo.
logically lower, such as certain
epochs in the Deronian period. AS
the oil fields were extended westerly
into Ohio, Indiana and Kentucky, oil
was found not only i'll those i'll which
| it occurred in Pennsylvania, but in
later formations such as the Jurassic.
In the Rocky Mt Plateau region
both coal and oil were found at first
only in the Cretaceous, a later and
higher period than the Jurassic. 1t
was thought for a long time that
thoseA two important minerals were.
in the West only found i'll the
Cretaceous. The Cretaceous has been
divided into several formations to
which have been given different
names by different geologists. Using
the older nomenclature, these are
from the top in the descending order,
the Laramie, Fox Hills, Ft. Pierre,
Niobrara, Fl Benton shales and Da
kota sandstone. The Laramie was the
coal bearing formation Those below
it carried oil.-the Dakota sandstone
being considered the best in Wyo-
ming. s
In earlier years the writer did not
consider Nevada promising field
for oil, because the Cretaceous rocks
were little in evidence, and those that
appeared were simply the solidilied
sediments derived from the erosion
of earlier eruptions and therefore like
ly to carry very little animal life or
vegetable lecemains. The developments
OF later years has caused him to,re-
wise his carried opinions. For one
thing, later geologists have brought
the Laramie formation mainly UP
into the Tertiary period, and some
have even brought the Fox Hills
group upsinto it. Furthermore, oil
has been faundsin Wyoming in form
ations now known or, considered to
be the Mioccne epoch Of the Ter-
tiary period. In.one case at least oil
has fbeen found there i'll formation
as low down in the geologic scale as
the Jurassic. In California, Oklaho-
ma, Texas, Mexico. and elsewhere oil
has .been found in both the Eocene
and Mioccne rocks of the Tertiary
period. N#a&
Now, it is recognized that large
part Of what is known as the Great
Basin was under the sea during the
Jurassic. period, while at that time
the Wahsatch range on the east and
| the Sierra Nevada range on the west
had but limited elevation. At the
end Of the Jurassic or Beginning Of
the Cretaceous there were extensive
|upheavals of these twosranges while
lateral pressure threw what. is now
the Great. Basin into a large, flat
semi-contincntal arch, which was to
a large extent above the sea dur
ingg the Cretaceous period But fur
tl,er volcanism occurred, the arch was
broken by north and south as well as
cross faults, the Basin ranges began
to take shape, while certain fault
blocks sank beneath the sea, Or arms
or esturaries Of the sea, or. saline,
Y. t 8aif