Page 62 - 1915, Springs of CA.

58 SPRINGS OP CALIFORNIA.
of the creek and along its southern bank. They range in temperature
from about 100° to 140° and from mere seepages to flows of 7 or 8
gallons a minute.
The thermal waters issue from a gneiss that is exposed along the
creek for a distance of 200 yards or more. Above and below this
exposure the rock is granitic and in some places contains small
garnets. The crystalline rocks are overlain by a series of shale,
sandstone, and limestone whose structure in the area north of Arroyo
Seco is well shown by the beds of massive, buff-colored sandstone
that dip about 45° NE. A western limb of this structure was not
seen, though it may exist in the mountains farther coastward. The
observed dips suggest that Arroyo Seco here crosses a zone of intense
pressure in the crystalline rocks.
The springs received their name from an Indian or Mexican word
that means "the place where meat is cured by drying," and dates
from the early days of the cattle industry. The springs have thus
been known and used for many years, and they were early visited by
campers, when the only access was by means of a difficult trail.
Several years ago a well-graded wagon road was built southward from
Jamesburg across the mountains and down into the canyon, and the
springs are now easily reached by stage. In 1904 a stone hotel was
built, and other improvements have been added yearly, so that in
1909 there were ample accommodations for 75 people, though a larger
number has been taken care of by the use of tents. Water from
two of the largest springs has been piped to tub and plunge baths,
and a vapor bath has been constructed over the hottest spring, which
issues in the creek bed.
Analyses of two of the thermal waters were made. These waters
are noticeably sulphureted, and the analyses show them to be only
moderately niineralized. The water of the Arsenic Spring has a
distinctly yellow color, which in a few other springs has been ascribed
to alkaline sulphides in solution.
At the north edge of the creek, a few yards above the hot springs,
there are two cool springs in which iron is deposited. An analysis
of the easternmost of these springs is tabulated with the hot springs.
The identity of an early analysis 1 purporting to be of water from
these springs seems questionable, as it does not accord with the later
analysis.

i California State Mineralogist Thirteenth Kept., p. 514,1896.