gold, and of Oregon also, was noticed by Prof.
J. D. Dana, and recorded in his geological
report of the country. In Hunt's “Merchants'
Magazine” for April, 1847, is a very decided
statement by Mr. Sloat respecting the richness
of the country in gold, made from his observations
there the two preceding years; and he
confidently predicts that its mineral developments
will greatly exceed in richness and
variety the most sanguine expectations. In these
years the Mormons connected with the army
were known to have gathered some gold upon
the banks of the streams, and the Mexicans and
Indians also. A party of three Americans, two
of them Mormons, were on Feb. 9, 1848, at
Sutter's mill on the American fork of the
Sacramento, near the town of Coloma in El Dorado
co., engaged in repairing the race, which had
been damaged by the spring freshets, when the
little daughter of the overseer, named
Marshall, picked up in the race a lump of gold
and showed it to her father as a pretty stone.
The discovery did not immediately attract
much attention; and the Mormons particularly
sought to prevent the facts from being made
public. The Rev. C. S. Lyman, in a letter to
the “American Journal of Science,” of March,
1848, says: “Gold has been found recently on
the Sacramento near Sutter's fort. It occurs
in small masses in the sands of a new mill race,
and is said to promise well.” The news spread
rapidly, and caused an unparalleled tide of
emigration to pour in from Mexico, South
America, the Atlantic states, and even from
Europe and China. (See California.) In
August of that year Governor Mason reported
4,000 men engaged in working gold, and a daily
product of the value of $30,000 to $50,000.
The earlier diggings were mostly deposits resting
upon the upturned edges of argillaceous
slates, the gold being found entangled in these
under the sand and gravel, and also more or
less mixed through the superficial layers. A
large proportion was picked out by hand at
many of the diggings, so abundant were the
coarse pieces. Attention was early directed
to the gold veins, and in 1851 regular quartz
mining was commenced at Spring Hill in
Amador co. In 1857 numerous mills, most
complete and thorough in their construction,
were in operation over a great part of the
country; and mines were opened at greater
depths than gold is often worked in other
countries. A shaft of the Mount Hope mining
company in Grass Valley was carried to the
depth of 241 ft., reaching the vein at 350 ft.
following its slope, and the richness of the
veinstone at this depth gave full encouragement
to the belief that these repositories were
permanent and inexhaustible. Many other
mines were worked from 150 to 200 ft. in depth.
In California, though gold is found E. of the
Sierra Nevada, among the mountains of the
coast, and in various other localities, the great
gold region is on the W. slope of the Sierra,
and extends from about lat. 35° N. northerly
to Oregon, a distance of about 500 m. The
average breadth of this gold belt is about 40
m. The principal mining operations have been
confined to a central area extending N. and
S. about 220 m., between the parallels of 37°
and 40°, and embracing Mariposa, Tuolumne,
Calaveras, Amador, El Dorado, Placer, Nevada,
Sierra, Yuba, Butte, and Plumas
counties. According to William P. Blake,
gold-bearing veins on the W. slope of the Sierra
Nevada occur in or are closely associated
with clay stlates, sandstones, and conglomerates
of the secondary period; also in hard
and compact granite, in greenstone or dioritic
rocks, and in dolomite and metamorphic
limestones. In the Coast mountains they are
found even in the partially metamorphosed
stratified formations of the cretaceous period.
The largest and most extensive veins exist in
the region of the metamorphosed secondary
rocks, varying in width from a few inches to
20 or 30 ft., and generally conforming to the
dip and strike of the strata. “The most
extensive vein of the state,” says Mr. Blake,
“and perhaps in the world, is known among
the miners as the ‘mother vein,’ and extends,
but with some considerable, breaks and
interruptions, from Mariposa northwestward for 80
or 100 m., following a zone or belt of Jurassic
slates and sandstones, and closely associated
with a stratum of dolomite or magnesian rock,
often a magnesite, filled with reticulations of
quartz veins and charged with pyrites.” The
chief production of California gold has been
obtained from placers. The great placer region
extends over the central counties from Mariposa
to Butte. The deposits occur not only in the
beds of the streams, but also upon the hillsides
and tops, where ancient watercourses are
supposed to have been. Sometimes they are found
under enormous accumulations of sand, clay,
gravel, and even of tufa and lava; the smoothly
worn stones are thoroughly cemented together,
and form a solid conglomerate or “cement;”
the auriferous deposits consist of gravel and
bowlders, varying in size from a grain of wheat
to masses weighing many tons. These hills on
the W. slope of the Sierra Nevada cover a tract
of country in places 50 to 60 m. in width, and
rise sometimes to the height of 4,000 ft. They
are traversed by numerous streams, whose
sources are in the Sierra Nevada. Subject to
sudden and extreme freshets from the melting
of the snows and from the long continued rains
of the wet season, these streams excavate and
sweep down the loosely aggregated rocks, and
wear deep cañons and gulches, which extend
toward the valleys of the Sacramento and San
Joaquin. Thus it was the same agency which
impressed this peculiar feature upon the topography
of the region, and spread the gold from
the veins in the hills through the ravines and
down into the valleys. Even upon the elevated
plains quite to the west of the hills gold is
collected in strata of sand and clayey deposits,
which cover the surface to the depth of 15 to
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GOLD