Fresno County CA Archives History - Books .....Geology Of The Valley 1892
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Book Title: Memorial And Biographical History Of The Counties Of Fresno, Tulare, And Kern, California

GEOLOGY OF THE VALLEY.

  The geology of this great valley is a wonderful study. The student will here
find ample field for investigation, and volumes could be written thereon and yet
not begin to exhaust the subject.

  As yet writers are left in a measure to their various ideas and speculations
as to the time when this great valley was made, and as to the exact causes which
culminated in preparing this fertile region for man's habitation. The general
topography and geological features of this valley leave no doubt upon the mind
of the average man that it has been in some remote period an inland sea, whose
waters have for ages received the wash and wear of the surrounding mountains
until at the lowest depression deposits of diluvium thousands of feet deep have
been made, which have been builded upon by vegetable matter and soils formed by
the recedence of the waters. The foothills bear traces of having been worn by
some mighty stream, and are covered by the decomposed granite, gravel, lava and
humus of ages. From their base the land gently descends and does not lose the
volcanic appearance of the soil until it reaches the general level of the
plains. The richness of the soil of this great valley is undoubtedly due to the
glacial period. The soil is seemingly made from the granite rocks and lava,
ground into a paste by the glaciers in the mountains and passed down into the
great inland sea by other glaciers, and great bodies of water seeking a common
level.

  John Muir says of the Sierras: They are everywhere marked and adorned with
characteristic sculptures of the ancient glaciers that swept over this entire
region like one vast ice-wind, and the polished surfaces prod needy by the
ponderous flood are still so perfectly preserved that in many places the
sunlight reflected from them is about as trying to the eyes as sheets of snow.
While nature's great glacial mills have ground slowly, they have here ground
exceedingly fine, and have been kept grinding long enough to prepare soil for
any alpine crop. Most of the soil has been borne to the low lands, where man can
plant and till it, leaving the high regions generally bare and uninviting.

  Less than 3,000 feet below the summit of Mount Ritter, we find tributaries of
the San Joaquin and Owen's rivers bursting forth from the eternal ice and snow
of the glaciers that line its flanks; while a little to the north are found the
highest affluents of the Tuolumne and Merced. Here we find the fountains of four
of California's principal rivers within a radius of a few miles.

  When nature was preparing the great American continent for man's
habitation-first by the ordeal of fire, as shown by volcanic action which heaved
to the surface all minerals for man's convenience and use,-then came a time
demanding a radical change to grind down the mighty mountains and prepare a soil
upon which man could produce vegetation to sustain life. Then came the period of
ice, when the mighty glaciers froth-New England to the shores of the great
Pacific ocean were put to grinding and planing away the stupendous mountain
ranges stretching away across the continent, when the high lands about the
sources of the great Mississippi river were being planed down and the debris
carried down to form the great valley along that stream to the Gulf of Mexico.
Then too the ice was planing down the old lava slopes of the Sierras, and to
their action is due the uncovering of the gold fields, as also the gold they
ground out of the quartz, and the alluvium that made the inexhaustible soil of
this greatest of valleys.

  No prehistoric remains have been reported as found within this valley; but
stone mortars, pestles, and arrowheads have been found, it is reported, in
Pliocene gravel, at Murphy's Camp, Shaw's Flat, Columbia, Springfield, Tuolumne,
Table Mountain. Sonora and Knight's Landing. Hills and mountains contain bones
of the mastodon, elephant, rhinoceros, hippopotamus, horse, camel, whale and a
quadruped resembling a tapir. Oyster shells fifteen inches long have been found
at Coral Hollow, and Oyster Peak near Mount Diablo is named for its fossils. It
is claimed that part of the skull of a man was found in sinking a shaft in one
of the mining districts at a depth of 130 feet, under four successive strata of
lava, which if true would indicate that man was on this coast prior to the great
eruptions of this portion of the earth.

  Professor Amos Bowman, of the State Geological Survey, thus defines certain
eras in the geological history of California:-

  First, the Pliocene, or ancient eroding period, during which these deep
"dead"-river channels were cut into the "bed rock."

  Second, these Pliocene channels filling up with gravel, or the choking, or
damming period.

  Third, the active volcanic period of the Sierras, where the gravels were
capped with lava and volcanic ashes.

  Fourth, the cold or glacial period, when the slopes were covered with living,
moving glaciers.

  Fifth, the modern erosive or more recent period, during which the present
river channels were formed crossing the old channels at various angles.

  There seems to be no controverting the theory, or we may well say fact, that
the great San Joaquin valley was at one period submerged with the waters of the
Pacific ocean, which left upon their subsidence a soil of adobe that has since
received a coat or deposit of sedimentary alluvium. The soil of the valley
largely formed through glacial influences belongs to the secondary formative
period. The mountains are of volcanic substances. Trap or basalt is the leading
rock, although porphyry, syenite, slate, and especially carbonate, or magnesian
limestone are found.

  In attempting to define the several geological formations, we will assume that
the mountains and valley are without breaks in their formation, and as it would
appear if all the groups of formations were present at one place in their
natural order. But this seldom occurs. These formations are very much broken and
disturbed, presenting a great variety of structures. Supposing we were to
examine a section of the earth in its original condition before any disturbing
cause disarranged the several strata, and beginning at the San Joaquin and
extending to the top of the Sierras, the rocks, strata, etc., there would be,-

  First, soil and alluvium. The conclusion will be readily reached by an
observing person, from the soil and vegetation of which this is the debris, that
this formation is exceedingly rich for agricultural purposes. This deposit
covers almost the entire surface of this great valley, varying somewhat as to
depth, and in fertilizing strength, or rather special adaptation to certain
products. The higher valleys and hills are not deficient, as a rule, in depth of
soil, and in some of the smaller basins it reaches a depth of from ten to twenty
feet, sufficient to support groves of immense trees. It is impossible to give
the exact depth of soil in any one locality.

  We give figures of a well bored some years since near the Chowchilla ranch,
and within two miles of the river. Total depth, 297 feet. Two feet, surface soil
and sandy loam. Through a space of ninety-eight feet was found fine sand
streaked with thin layers of clay. The sand was similar to that of the plains,
then one foot of solid hard-pan. Then, passing through ninety-five feet, the
strata were found to be composed of various qualities of sand, from that of
quick-sand to coarse gravel. Then through 101 feet was found to be a compact
mass of hard blue clay, such as is found by the grinding away and decomposition
of granite and other rocks. After passing through this flowing water was obtained.

  Secondly, the conglomerate formation, comprising a deposit of shale, clay,
boulders, sand, and fragments of all the lower strata, worn and loosely cemented
with calcareous matter, which was evidently deposited when most of these
mountains were under water. There is found in this formation evidence of floods
and washings of the sea, fossils of wood, bones (mostly of marine animals),
shells of mussels and other mollusks, turtles, such as are now found in creeks,
with occasional impressions of sea weeds. This formation has no regular
thickness. It is sometimes found in piles against the shale to a depth of from
thirty to forty feet. In the foothills it extends over the Pacific coast,
stratified by the action of water.

  The third stratum, or bituminous shale,- "chalk rock"-varies from a white to a
dark color, and from a very fine to a very coarse texture, as also from a soft
and friable condition, crumbling between the fingers, to a flinty hardness, that
withstands the hardest steel. In this stratum are found tree-like concretions of
hard sandstone 50 to 100 feet long, and also bones of marine monsters, such as
whales, seals, etc., and occasional beds of lignite, an impure or immature coal,
three or four feet thick. Some of this coal, however, is of a fair quality. In
the white and gray chalk beds are found microscopic remains of diatoms, sponges,
and other organic structures. In fact, this formation seems to be composed of
the remains of these microscopic beings. Therefore, this formation must have
taken place under the water, when the present Coast Range was near the level of
the sea, and when perhaps the Sierra was the eastern barrier to the Pacific ocean.

  The fourth, or sandstone, formation, differs but little from the shale, except
the quantity of sand contained therein, not very firmly cemented, and mixes more
or less with the shale in alternate layers. The fossils in each are similar.
Beneath the sandstone are found the upturned edges of the clay slates. These are
interstratified with a limestone, copper ore and quicksilver. As the old red
sandstone, and the "true carboniferous" rocks so called, are not found in
California, it was long supposed that no valuable coal would be found in the
State. Recent discoveries of that valuable commodity in large bodies in the
Coast Range have/set aside such theory. These coals contain far more solid
combustible matter, and less incombustible material, than most tertiary coals.
It is really more properly "lignite," and belonging to a later period than that
of the real coal formation, lying in different strata. The rocks are of the
upper secondary age, sandstone and shale, and were formed by alternating
depositions in salt and fresh water.

  The fifth, or limestone, formation, is more or less metamorphic, and the rock
is crystalline. This lime rock is of very good quality, and when properly
selected is an excellent building material and easily worked, and is found in
large quantities. In places there are unexplored caves of considerable extent.
No important fossils have been reported as found in this formation. It is not
found in distinct horizontal strata but generally in masses, as having been
thrown into heaps when in a semi-plastic state by the upheaval of underlying
formations.

  The sixth, or metamorphic, rock, was undoubtedly originally stratified, but
now broken and thrown into endless confusion. There are alternations of slate,
granite, limestone, quartz, gneiss, etc. It is the most prevalent rock of these
mountains occupying a large portion of their area, and contains copper, gold,
quicksilver, iron, and has recently been shown to contain petroleum of vast
variety and excellent quality.

  The real economic value of this formation in these mountains is as yet but
partially known, and therefore little appreciated. Undoubtedly a river ran
nearly in the course of the present Stanislaus, in the Pliocene age, and was
destroyed by a lava flow, which rose to the level of the banks, leaving no bed
for the water, and continued to build up until it assumed a mountain appearance,
with serpentine, steep sides, and a bare and level top. Sinking down through the
middle of Table mountain, the miners passed through 150 feet of basalt, 100 of
volcanic sand, fifty of clay and sand, thirty of gravel (the lowest ten feet
being rich in gold), and then struck the slate or bed rock.

  The seventh or granite formation, makes up the bulk of the Sierra Nevada
mountains. This granite has undoubtedly at some period been stratified, although
nearly all evidence of such a fact has been lost. Where exposed it crumbles
readily. The lowest rock is granite, but differing greatly in its composition in
different localities. Overlying this are found shales and sandstones of the
crustaceous period,-a very recent geological age; hence the conclusion that
these granites are but the metamorphosed sedimentary rocks of past ages.

  During the deposition of the cretaceous rocks, this country and the great San
Joaquin valley formed a part of the bottom of the Pacific ocean. Time swept on,
however, and the hour which closed a period of the world's history came, and
with it the upheaval of the mighty Sierras.

  Then undoubtedly followed a long period of comparative rest, and perhaps the
period when mine deposits or upheavals were made. Large rivers were formed, deep
channels and gorges cut through the uplifted rocks, which were so heated by
volcanic fires as to crumble when coming in-contact with water, and the heat
also metamorphosed the disintegrated parts, sands, mud, etc., and they became
hard rocks. In places, interstices veins, etc., were filled with the melted
rocks from below, through others circulated hot water, charged with the various
valuable minerals, gold, silver, copper, etc. These were slowly deposited where
now found in large quartz ledges, as also later in gravels where glacial mills
had ground them down and washed them down the streams along the foot-hills and
into the valleys.

  The climate of this great valley has been spoken of in the general history of
the State, but will be given special local attention in the history of counties
elsewhere in this work, as also will the various products. We wish now to call
the reader's attention to the condition and aesthetic appearance of this great
valley.


Additional Comments:
Extracted from:

Memorial and Biographical History
OF THE COUNTIES OF
Fresno, Tulare, and Kern, California

Illustrated
Containing a History of this Important Section of the Pacific Coast from the
Earliest Period of its Occupancy to the Present Time, together with Glimpses of
its Prospective Future: with Profuse Illustrations of its Beautiful Scenery,
Full-page Portraits of Some of its most Eminent Men, and Biographical Mention of
Many of its Pioneers, and also of Prominent Citizens of to-day.

"A people that take no pride in the noble achievements of remote ancestors will
never achieve anything worthy to be remembered with pride by remote
descendants." -Macaulay.

CHICAGO:
The Lewis Publishing Company.
Undated, but OCLC lists a publication date of 1892


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