The Corvallis gazette. [volume] (Corvallis, Or.) 1862-1899, 1893-10-13
THE OLDER COAST RANGES.
With More Recent Geological
Formations in Benton
County.
BY IoHN RAY.l

BY JOHN RAY.
Over the Rocky Mountain region. and west
occur isolated areas and outcropping mountain
masses and ranges of Eozoic rocks which have
been largely concealed by later sedimentation."
-WINcHELL.
1t may appear singular that while the
U. S. geological surveys have done so
much for California, Washington, Idaho
and Montana so little attention has been
paid to Western Oregon. This, perhaps,
may be explained in this way, that, in
those states, there was some probability
of finding material of economic value,
while in Western Oregon, with the label
it has long carried of its geological posi-
ton, nothing of the kind could be
expected.
The position given us by leading
geological textbook, published as late as
1888, in speaking of the uplifts of the
Sierra and Coast Ranges, says 'The Coast
Range was not formed until the end of
the Miocene." Other textbooks take
the same position. Neither is there in
those books but little indication that
other than Miocene strata is to be found
in this part of the state, though. Prof.
Winchel1 suggests an ancient land in this
locality.
We desire to say here that so far as a
Miocene uplift is concerned they are cor
rect, but by far the most prominent and
pronounced formations have been over
looked. There was series of wel1-writ-
ten articles On the geology of Oregon,
Washington, Idaho and Montana by Her
bert Lang in the Oregonian about 1886,
but Western Oregon had only few lines
devoted to it. The writer of this paper
at that time attempted to correct errors,
but, investigations then made had not
been sufficiently thorough to insist upon
claim when that claim, apparently, was
against all authorities. but since then,
with repeated examinations and study,
together with the work of the geological
surveys in the older Coast Ranges in
Northern California and published in
their several bulletins, and with the
archaeological departments acknow1-
edgement and determination of fossils
sent from this locality, enables me now
to speak with more certainty and exact
ness than previously upon these forma-
tions which have so long been overlooked.
LOCALITY.
The old county of Benton was bounded
on the east by the Willamette river and
on the west by the Pacific ocean. With
the exception of a. little sPliocene at the
western end land of which no further
mention will be made in this paper
this territory is cut through, irregularly,
north and south, by three other. forma-
tons. 1--WE have called Eocene and Mio-
Gene each one.) These three formations
are each conspicuous in their hills or
mountains The central or Oldest has
the greatest elevation and boldest out
line. To the west is found the Miocene
next in prominence also occupying the
largest amount of territory. as well the
range of mountains of this age has
received the title of Pacific Coast Range.
To the east of the aforementioned is
found the Eocene, and probably older.
The latter is only conspicuous in the
beauty which the low gentle contour of
the hills lends to the landscape. |
Standing Immediately west of Corvallis
and looking to the west and upwards is
seen the dark, undulating outline of a
range of mountains backed by the hori-
zon. Running the eye from north to
south distance of twenty-five miles or
more, it is seen this range nearly forms
the arc of circle, the north point of the
arc resting about six miles from us direct
ly north, the center about Mary's Peak,
thence running southeast until it is lost
in the distance. Ut should be stated
here the range is broken just south of
Philomath and begins again at the south
end of Cardwell hill. Opening about
two miles wide. This opening no donbt
was the entrance of the waters Of the
Pacific ocean to this valley long before the
Miocene hills were brought forth.) This
range is the eastern face of the Oldest
formation. In the foreground and rum
ming east to the river and on to the Cas-
cades the space is filed with numerous
low hills. These are generally of Eocene
formation or the equivalent of the
Chico TETON of California. :.
THE VINEYARD HILL. -
It is at this northern point our work
begins. This portion Of the range has an
elevation above the valley of at least
1900 feet. Springing from the chain
running in south-westerly direction il
turns abruptly to the east for one mile,
then again takes its northerly direction.
This sudden turn to the east presents a
fine sloping breast to the south. It is
upon this breast and the foreground with
the connecting range we call attention
:! SURFACE MATERIAL. @
AS we approach the base of this hill
following the wagon road about one mile
the ground, while undulating, gradually
rises some fifty. or more feet. On the
road. as we pass. several white strings OF