The Hawaiian gazette., 1906-05-15
GEOLOGY OF
CALIFORNIA
CONTINUED from page -
GREAT GEOLOGICAL IAuL1

GREAT GEOLOGICAL FAULT.
The fault passes about one mile west
of tie Southern Pacific railroad bridge
which spans the Pajaro river. At this
point when an earthquake occurs the
wagon road which is cut into the high
bluffs OF the river is filed with broken
shale thrown from the bluffs. Near
the bridge are two snbsidences form
ing lakes. South of the river In this
fault on the summit between the river
and the town of san Juan South is a
lake, upon the shore Of which are live
oak trees over 800 years old. In 1890
at this point the land on the nortir asst
side of the fault was raised two feet
higher than the land on the southwest
side.
This. fault passes near the town of
San Juan South, for here The fault
runs through valleys on the northeast
SLOPE of the Gavilan mountains to Dry
Lake valley. Here the land on the
northeast side of the fault hus been
raised about fourteen feet higher than
the land on the southwest side of the
fault. This must have occurred i'm re-
cent years (geologically speaking), as
the bank forming the rise has not been
washed away nor the holes at the foot
of the bank filled. When Big Rabbit
valley on the Topo Rancho, near the
southern end of San Benito county, is
reached the fault is on the southwest
side of the Gavilan range of noun
tains. In former ages the formation
on the northeast side of the fault has
been raised 500 feet higher than that
on the southwest side.
The core of this faulted and fissured
anticline at this point rs serpentine and
jaspers, two metamorphic rocks made
bv the alteration of sandstone and
shale, the jaspers being burnt shales
which have been subjected to hot aka
line solutions which have ascended
through assures in this anticline. Ser
pentinous and jaspideous rocks form
the core of this faulted anticline from
this point until reaching the northern
boundary of San Luis Obispo county.
From San Juan South to the northern
boundary of San Luis Obispo county
are numerous small lakes on the line
of this fault, which are filed with
water in the winter and are dry in
the summer.
Nhbii oiNA>l<h 10 o<tI
Northeast of the serpentine and
jasper core the shale and sandstones
are unaltered, but southeast of the
serpentine and jaspers the silica of the
shales is changed from insoluble to
soluble silica, making a rock very
white in color and light in weight. This
change in the silica has been effected
by hot alkaline solution, which has as
cended through the fissuIes of this an
ticline in great quantity. Diatoms are
found in these altered shales, which
We're born in the shales and not de-
posted.
This fault passes through Cholame
valley. Some years ago, during an
earthquake, a spring burst forth in
the valley, where it was dry land be-
fore. The fault is marked by deep cuts
when passing through the Carsa
plains, San Luis Obispo county. The
fault passes near the head of the
Guyana river, Santa Barbara county,
where it is shown by lakes and assures
cutting through spurs of the hills. 1t
then swings toward the east around
the southwest slope of Mount Pinos, as
is shown by lakes, assures and valleys.
III
shown by a fissure that looks like a
railroad cut and extends for miles.
Laguna, Elizabeth and Alpine lakes
are on this line of fault East of the
Southern Pacific Railroad, at Harold,
Los Angeles county, it runs along the
northeastern slope of the San Gabriel
mountains and is widened by valleys
cutting spurs of the mountains at right
angles, springs and lakes. 1t runs
through Cajon pass, passing the city
of San Bernardino, through Mystic
lake, near San Jacinto, through Ten
villega valley, thence down the dry
bed of the San Felipe to the Colorado
desert, thence through Volcano lake
and New river (made by an earth
quake in 1S4W to the Colorado river
and from the Colorado river to the
Gulf of California.
Besides the fault described above
there are a number of faults scattered
throughout the length and breadth of
the coast ranges. A number of similar
faults exist in the Wasatch mountains,
Utah; also in the mountains in the
states of Oregon. Wyoming, Colorado,
New Mexico and other states. Faults
exist in the Appalachian range, from
Maine to Georgia, distance of 1900
miles. In fact, in all mountain ranges
throughout the world where these
faults are found earthquakes may
occur. California is as safe as other
countries, as no one can say where
the next earth movement may happen.
"A. S. Cooper. in the San Francisco
Chronicle.