The morning news. [volume] (Savannah, Ga.) 1887-1900, 1899-01-30
CALIFORNIA MOTHER LODE.
A BODY OF RICH QUARTZ IN THE
SIERRA NEVADAS.

of 200 MiIeS-ItS Peculiar FOrma-
ton and the Origin of Its Gold De-
DositS-Past ana Present Methods
of Mining-The Riches of the Lode
From the New York Evening Post
Along the middle foothills of the Sierra
Nevada mountains. ana about twenty
miles from the high SUBMITS Of that range
there runs for a distance Of nearly 200
miles a great ventricular arm or body Of
quartz It Is mostly from two 20 twenty
feet n thickness, often pure. crystalline,
marble-nke structure. but again broken
into by dikes of errutive rock, cut by these
in some places into mere ribbons and
threads. then resuming its spotless integ-
rty and texture, swelling its enormous
bulges, and spreading, as at Quartz noun
tam, over a whole broad hilL
For 200 miles or more the geological
phenomenon may be traced. It is cut off
by the granite at the southern end of
Mariposa county, but it ranges north
through Touloumne. Calaveras, AmadoT,
Ell Dorado. Places. Sierra Nevada and
Butte counties, and finally disappears.
great meteorological serpent was exposed.
but all lay protected by some thousands Of
feet of incumbent material, which has
since been dissolved or torn and washed
away, and in these parts where the vein
flashes bare the erodng agents have
thrust their resistless teeth into its very
vitals and are now gnawing it away, its
several particles being carried off by that
unimpedable vehicle, water.
. This is the mother lodge Of California.
Its formation is due to a great lateral
rift which has been made by the up
heaval or the setding of these mountains,
and this rift filling with the silcated per-
colating waters of the thermal depths be
meath, has received the precipitate, which
has concerted, and so formed the sub
stance of the vein. The measure in which
this body mostly lies is series OF black
states from one to four miles wide, called
the Mariposa beds, and this slate Itself
Is cut with volcanic or eruptive dikes
which have been belched up out of the
earth, broke through, cooled and harden
ed there, and now stand, with their crys-
talline masses, some green, some gray
under names of schists and diorites, of
hornblend, porphyry, and else. The strata
or layers of slate do not lie fiat. but stand
on their edges, resting some hundreds Of
feet below upon archean granite. These
states were deposited by the clay-lke pre-
cipitations of a great sea. which then
spread over the area of these hills; a
Jurassic sea. And what we now look upon
as the high Sierras. a stupendous. sublime
chain of mountains, 400 miles long and
sixty miles across was then low, round
ed series of knolls the remnants of noun
tains which had been worn off and had
fallen into senile decay.
qnf fa1
tain structure is caused by the Unfolding
of the strata of the earths crust yielding
to lateral pressure, such as an adjacent
ocean will exert. The strata are pushed
so that they are bulged outward and up
ward, like a pile OF layers of putty push
ed laterally from opposite sides. II is
along lines of weakness or fracture in the
earth's crust that the strata will yield in
this way, which accounts for the uplifts
occurring in narrow trends over long dis
tances, and so forming a range of noun
tains, instead of a massing of them to-
gether, without indicating strike or direc-
ton. When the pressure which the
weight of mountains exerts upon the
earth's crust had been relieved by the
long processes of denudation, and the
mountains had become worn down almost
to their roots there was nothing to with
stand or counteract the intense lateral
oceanic pressure, and consequently there
came a terrible upheaval of strata along
the seam of weakness, and great noun
tain range was born. The rise was from
the easternmost margin of the old range
and it lifted the strata like a giant block,
heaving it up TO a. hight of many thou
sands of feet-thousands of feet higher
than they now stand-the east side being
precipitous and craggy but five miles
from summit to base, while the western
side graded down gradually and found the
level a. a distance Of about forty-five or
fifty miles.
II was by this uplift that the old Jur-
assic states were tilted on their edges
as we find them to-day along the mother
lode, and when that tilting process oc-
CURED, and the eruptive stones arose
from beneath and cut into them there
were formed by these movements an
through the slates more or less vertical
splits or cracks or assures. Into these
assures ran the hot waters which are
continually circulating through the earth,
and these waters We're impregnated with
various minerals and metals particularly
with sulphur and gold, which had been
leached out of the rock substances con-
tanning them, and carried in solution along
with silica and else. As soon as the fs-
sures in which they were deposited were
opShNNf TIC WATERS btltlS unQef pressure
naturally sought passages of escape. The
pressure being released aud cooling pro-
cesses intervening, condensation raptjlv
set in, and so the veins were formed
II, therefore, occurs that all throughout
these states and the circumjacent rock
wherever these splits have occurred
away as far as the mother lode extends
there are innumerable veins, which are
often entirely inclosed in the states. al
though more commonly wedged between
the slate and some eruptive rock az what
is called the contact" These splits are
not perpendicular but are inclined as
are the beds OF the slate itself at an angle
of perhaps 45 degrees from a plane; and
so the veins dip" as il is termed in
mining pariance, the bottom foot wan
often being slate, and the top or hanging
wall greensboro. Veins of this nature are
apt 10 be rich, as the igneous rock has
come from depths.
popularity is that while these thanking
veins are often exceedingly rich in gold
the great central core is barren. or nearly
so, for il assays but an average of 81
cents 10 the ton. Nor are all the side
veins rich. They show inexplicable eccen-
tricities in the values of their metallic
contents. Some of them will give min
tests of $500 n the tou Will