Yerington times. [volume] (Yerington, Nev.) 1907-1932, 1919-10-25
Oil IN Mineral
and Lyon Counties
The Geological Evidence
BYI. G. KENNEDY, c. E.

senli-saline or brackish lakes, so that
| in some sections a thin series of
Cretaceous rocks were laid down.
At the end of Cretaceous and continu-
| ing through the Eocene period, fur
ther settling occurred, so that large
areas sunk beneath rather shallow,
seas or brackish lakes 1t was an era
OF warmer climate than the present.
and there was rather abundant Veg
citation il and around the seas, estu-
aries, and saline lakes and marshes,
The whole Tertiary period, and
especially the Miocene and Pliocenc
epochs of it was the age Of large
mammals OH land, while the waters
were filled with abundant life, in
Guiding reptiles coming in from the
Mesozoic era. Gu land roancd the
1nastodon, the camel the horse and
many other herbivorous animals now
extinct Water, soil and vegetation
were filled with small organisms
such. as diatoms and bacteria.
In Lyon and adjoining counties
most of the formation from the
Jurassjc to the present time are.
represented. The rocks Of the Juras
sic periods the Cretaceous period,
and the Isocene epoch of the Teriatary
period, So far as at present known,
are not well represented There is,
however, a thick series, Of rocks Of
the Miocene and Pliocene epochs,-
the Pliocene being the ,uppermost
are most often seen. Bones Of the
camel have been found i'll the sedi-
mentary formations on the slope Of
the Singatse or copper range west
of Mason valley. Many unidentified
bones of other still larger herbivorous
animals have been found in widely
separated localities, as witness the
large molar tooth and other bones of
some large animal recently found by
E. ]. Ross of this place.
As every where in Nevada, these
Tertiary rocks which were once
Approximately level, are now badly
tilted boken, faulted and sometimes
thrown into folds and domes Oil
as general thing will be found in
commercial quantities only on the
top OF domes or crests of anticlines
Often the surface over subterranean
| anticline will show a depression or
syncline in topograph-fornl, through
! the dip of the rocks on each side OF
this surface depression will indicate
! the anticlinal structure OF the rocks
below Oil shale or oil rocks may
outcrop at such places, but no oil
Twill be found in commercial quantities
in such rocks, because it has moved
l,up and out at these exposures, and
has been evaporated, oXidized and
washed away III the course OF time.
| Beneath such crests, however, there
MAY be better oil formation with an
unbroken anticlinal crest Such
places should be- selected for drill
ing; because less depth of drilling
will be necessary to reach the de-
sired formation than some distance
to one side, though the latter. be
lower in absolute elevation above
the sea.
Oil is sometimes found in sufficient
Quantity to be pumped in a mono
cline,-a monocline being where the
stratihed rocks have a uniform dip
some distance in one direction with
out folds and with but little difference
iii amount of dip. These monoclines
are often broken by faults. which
allowsta fault block to slip down so
that, the oil formation is sealed at
the fault by abutting against some.
impervious formation. In such cases
if a well is sunk below the fault and
in the higher part Of the succeeding
fault block pumping well OF usually
small yield may be had.
The foregoing may be briefly SUM
arized as follows
lst. Several strata Of rock which
do contain oil and may yield it in
commercial quantities exist in, the
counties named. .s ii
End Anticlines do exist in the
territory and those places should be
sought as the sites for wells.
| 3rd. Uuless an individual or COM
pany has money which they are will
ling to spend in random wild eating.
Ein an improved territory, the sites
lfor wells should be selected by COM
petent geologists, or practical oil men
who understand the main principles
)of oil geology.