The San Francisco call., 1905-04-08
EARTH is SINKING,
SAYS A SCIENTIST
Region About San Francisco Has Subside
Four Feet in Recent Times.
University of California Savant Thinks That
All Will Go Under Gradually.

BERKELEY, April S.-Scientists of
the University of California express
deep interest in an important bulletin
issued to-day by the university author
tiles, being the product of Vance c.
Osmont's researches in the coast
cisco.
The announcement is made by the
author Of the bulletin that the bay re-
gion is subsiding at an appreciable
rate constantly. there being proofs in
evidence that show a submergence of
four feet in very recent times.
1t is inferred by the scientist in Ques-
tion that gradually this region will
sink, so that the future may hold in
store for dwellers in the bay region a
series of experiences of more than
passing interest. Discussing this mat
ter. Mr.. Osmond says:
The recent subsistence which has affected this
region is well illustrated the mouths of all
Of the streams flowing into the ocean and the
bay. Russian River, Salmon Creek, the Este
ros Americana and San Antonio and brakes
Bay at their mouths are wide, ford-like bodies
Of water with very precipitous shores, while
the streams such as Petaluma Creek and Napa
Creek are mere sloughs in their lower limits,
meanering through bread nat tule land bor-
dered by steep hillsioes. That they represent
a submerged area is apparent TO the casual
glance. Certain evidence exists to show that
the suhmergence is going at the present
time in the vicinity OF San Francisco Bay
In recent excavations made at Shell Mound
Park, between Berkeley and Oakland, II was
found that the base of the shell beds are now
four feet below the ordinary high tide mark.
Since IL is evident that the mound is a "kitch-
en-midden." and therefore built on the land,
this fact proves that there has been in very
recent times a subsistence of at least four feet.
The topography OF this section then may be
placed at a somewhat advanced stage in the
geomorphic cycle, and. since this cycle must
have been lnaugursted not earlier than the
beginning Of the Pleistocene. the observer is
Immediately impressed with the enormous
amount of erosion which has taken place, and
the vast space of time represented by this the
most recent period of geological history.
After the intrusion of the pre-Franciscan
strata by the GRANTEES a great period of erosion
occurred, as shown by the great unconformity
existing between Franciscan and the older
rocks.
Upon this old. well worn surface the Fran
ciscan series laid down. the variety of the
sediments giving evidence OF frequent oscllla-
tions during their deposition, while the sharp
folding and faulting that mas taken place and
the volcanic intrusions attest the immense
amount Of movement subsequent to their depo-
sition.
During the Shasta Chico times probably the
whole OF this area was deep under the sea and
the Sierras were undergoing erosion. for lying
unconformaby upon the Franciscan. as shown
in many places outside of this field and sug-
gested by the heavy ebert conglomerate of Ca
nav valley is a vast accumulation Of thin
bedded shaies and sandstOnes in monotonous
rhynical succession. indicating deep water
unexplained conditions. At the most conserva- l.
tive estimate the Shasta-ChIco strata in this
territory have thickness of hve miles, and
they are probably considerably thicker than
this.