The Placer herald., 1865-02-11
NUMBER "a.
Geology of California.


Of thousands or millions Of years have pas.
sed awav since California arose from the
deep. but in geological eras the country is
new. The chief means Of determining the
age of rocks is by the fossils which they
contain. The earth has had various kinds of
animals at various epochs, each epoch hav
ing a higher fauna than the one which pre-.
ceied it. The fishes lived before there were
any reptiles; the reptiles lived before there
were any birds; the birds lived before there
we're any animals; and the mammalian
brutes had existed long before man appeared.
Each of the later epoches had its peculiar
forms of animal life; and it is by an exami
nation of the remains of each one Of these
animals, that the age of sedimentary rocks
are determined. These remains may be SO
small that the naked eye cannot distinguish
them; and Professor Brewer has numerous
specimens which cannot be Investigated with
out tho microscope. None of the large
Saurians-these wonderful lizards as large as
whales-haye yet been found here; but our
hills and mountains contain the bones of the
mastadon, the elephant, the rhinoceros, the
hippopotamus, the horse, 'the camel, the
whale, and an animal resembling the tapir.
These all lived once in California. Oyster
shells fifteen inches long are found near
Corral Hollow, and ammonites abound in
Shasta county-some of them u foot and
half in diameter. Our climate must have
been tropical in the era of this extinct fauna;
our valleys were great swamps; our noun.
tains were covered with uxuriance Of
vegetation which now exclusively belongs to
the equatorial regions. Man lived at the
same time; man in the lowest stages of
savageism, when the highest operation OF
his skill was to make an arrowhead or spear.
head of flint or obsdian.
The cretaceous formation, which contains
all our valuable coal and quicksilver, ex.
tends the entire length of the American
coast, from San Diego to Bellingham Bay.
About two hundred and liftyfve fossils, Of
which 95 per cent are of new species, have
been found in this formation. The fossils
found in the Jurassic gold bearing rocks Of
the Sierra have not yet been worked up.
From Mount Shasta to Mount San Jacinto,
all the high peaks of the Sierra are in a
straight line North of thirty-eight degrees
the peaks are volcanic. From the summit
of Lassens Peak, thirty craters Of extinct
volcanoes are visible. The evidence of their
activity is found in body Of lava tha. covers
ten thousand square miles, with which a
shape something like pear extends from
the vicinity of Orovlle to Mount Shasta,
which it surrounds. Appearances indicate
that the top of Mount Shasta for twelve
thousand feet from the summit downward is
lava. The plateau Of the Sierra Nevada or
high table land in Plumas, and the eastern
part of Shasta county, is covered with lava
which buries the gold so deep that the miners
can reach it only in few places where the
streams cut through it to the slate beneath.
The aurferous slate is very narrow in the
southern part of the Sierra Nevada; but it
widens out regularly as it approaches North,
and the richest diggings have been found
near the edge of the great bed Of lava, which
hides countless millions Of gold from the
miner.
South Of latitude thirly-eisht degrees
there are no volcanoes active or extinct in
the Sierra Nevada and the highest points
lise but one thousand feet above the general
level of the range. while at the North the
peaks rise from three thousand to eight
thousand feet above the surrounding noun.
tains.