The Corvallis gazette. [volume] (Corvallis, Or.) 1862-1899, 1893-10-20
Popularity of Rocks.


may all be said to be changed by meta
morphism, though those where clay o,
magnesia enter into their composition
soften more or less by exposure. While
the layers are built up seemingly in
blocks of from twelve to eighteen inches,
these blocks are again divided into thin
ner divisions, slate or flag, the lowest lay.
er the coarsest, changing rapidly in few
inches to finer, until they finish with a
clay. In the coarse grit, splinters OF
dolomite or ebert is quite common.
Again we have two thin sheets of deep
green clay, between which is light grey
sand. This now is exceedingly hard and
when polished resembles serpentine
through the clay being pressed little
here and there into the sand. Taking
the sand alone, it resembles agate
There is not much sand stone, but what
there is boulders, in place in the
strata, buff in color, fine grain and
schistose. This is the best rock on the
ground. There is one popularity about
it: is finely c1ouded with green, darker
near the edge of the boulder and spread
ing across the face till the green is lost in
the buff. A darker quartsite has this
green in stringers stretching into the
rock like the fingers of a mans hand.
This is in substance running about one
half inch wide and about the fourth of
this in thickness.
Excepting the smoother bedder shales
all the rocks, whether of sand or clay,
have a strange patchy appearance.
Small pieces of clay seem to have been
scattered around, then another heavier
sediment upon them has fattened them
out in angles and all kinds of shape,
making the faces uneven where any of
those pieces are. In the clay sandy
sha1es, footprints of birds and other
small animals are found. The latter
together with the serpentine shales, the
conglomerate at Vineyard, and black
do1omite at the foot of Cardwe1l hill. all
have been broken or scattered and, with
out changing the position of the frag-
ments, have been re-cemented. The SER
pentine in the smallest pieces, the con-
glomerate through pebble and paste, the
others in rather small pieces.
In bulletin published by the Geolog-
ical Survey, Washington, 1885, subject,
"stratigraphy of California" by Mr..
George T. Becker. says: Throughout
the coast ranges of California there
occur large irregular areas of rocks in
the condition ordinarily regarded as met
amorphic. They are characterized by
the presence of serpen ntine (perhaps
accompanied by some of the magnetism
minerals) or silica, or 10th. Of the Sec
ondary nature of the sihfcation there can
be no doubt since the quartz and opal
occur mainly as stingers, for the most
part occupying tiny cracks in the rock.
~ Where the qualification of the
metamorphic rocks is not obliterated,
they are seen to be greatly disturbed,
having been sometime broken into a
chaotic mass of fragments since cemented
by silica or serpentine, and sometimes
thrown into sharp plcations. In the
latter class of cases it is often clear that
p1ication has not been effected by fexure,
but by innnmerab1e fractures, the result
ing fragments often averaging less than
one quarter of an inch cube. These par
ticles were retained in approximately
their original position by mutual pres
sure, and have been re-cemented by silica.
The most striking instances of this char
acter are seen among thin rocks either
sandstones or sandy shales.''
Older Metamorphics.
We have specimens of these rocks from
the Alsea Valley, from the top of Mary's
Peak and from the Vineyard-Kings
Valley group. From the two former the
rock is Diorite, greenish grey in color.
The Alsea rock seems to have the most
quartz and in the form of crystalization
somewhat different. In the fe1dspar
paste, black needles or dots surround a
white spot. In the rock from the Peak
there seems to be two kinds of white
paste; the harder running in something
like chainlines filed up with the softer.
These with the black minerals sprinkled
in, also running in irregular lines, now
full and again flowing into fine thread
like lines. The Alsea shows pink cloud
ing, little disintegration in the black
spots and softer white. Mary's Peak
specimen is much more changed, show
ing more fully the loss or greater decay
of one of the whites. The hornblenda
too is dull black, separating into threads.
So far neither of those rocks have been
found in the latter group. But what is
plentiful is crystalline rock with little
or no feldspar. It is made up of black
angular in form, face uneven,
showing on portions of face deep green
and occasion1v bronze color. These