Camp,
and West Camp 4 miles from Middle Camp and near the mine of the
Himalaya Mining Co. The latter mine is about 12 miles N. 60° E. of
Silver Lake, a station on the Tonopah & Tidewater Railroad. A visit
to the region was made by way of Silver Lake as the nearest railroad
point, but a guide familiar with the different localities could not be
obtained and only the Himalaya mine was examined. Remains of ancient
workings with stone hammers are reported to have been found at all of
the turquoise deposits mentioned above. One small crude stone hammer
was found near the Himalaya mine at the time of examination.
The
Himalaya turquoise mine is on the west side of a group of hills lying
northeast of Silver Lake. The hills are rather rough and from them
broad debris-filled washes with low ridges slope toward Silver Lake
Valley. With the barometer reading 900 feet at Silver Lake the
elevation at the turquoise mine was 3,150 feet above sea level. The
hills are bare, vegetation consisting chiefly of scattered sagebrush
and a few cacti. No water occurs at the surface near the mine but a
supply for the camp was obtained from a well. The camp is in a draw
about half a mile southeast of the mine. The topographic relief between
the gulches and hills around the deposit is from 100 to 500 feet.
The
chief workings are in the northwest side of a ridge with rather steep
slopes. Other openings have been made to the northwest across a gulch.
The workings lie in a north of east and south of west direction and
consist of many tunnels, crosscuts, stopes, an open cut, and a shaft.
The open cut is nearly 75 feet long and 20 to 40 feet deep and extends
from the surface to the tunnel level. A tunnel 75 feet long connects
the bottom of the open cut with the surface of the hill and another
tunnel enters the open cut from a higher level on the hill side. From
the open cut another tunnel has been driven over 100 feet farther south
of east. Workings from this tunnel consist of about 100 feet of
crosscuts, a large shaped room or downstope 10 feet deep, and a 25-foot
shaft in the bottom of the room. Five other irregular benches and
tunnels were made in the walls of the open cut, presumably before the
latter was carried to its present depth. The dumps of waste rock from
the workings cover a large area on the hillside and from them there is
a fine view across the desert over Silver Lake Valley to the mountains
at the south end of Death Valley.
The
turquoise is associated with granite porphyry and this is included in
an area of granite. A series of older rocks, probably of pre-Cambrian
age, consisting of biotite schist and gneiss, hornblende gneiss,
biotite granite gneiss, and pegnatite, outcrops south of the camp. The
contact of the granite with this series strikes north of east. Some of
the granite contains small hyacinth-colored garnets, and the feldspars
are colored a strong pink by inclusions of hematite dust. The granite
porphyry in which the turquoise occurs has been decomposed to a spotted
buff and gray color. Rough hard ledges of quartz and sihcified porphyry
outcrop on the hills around the mine. Some of these ledges are heavily
stained with limonite and hematite. In hand specimens of the decomposed
porphyry, phenocrysts of white decomposed feldspar, glassy quartz, and
biotite are recognized in a groundmass. Under the microscope were
observed orthoclase
