Page 143 - 1915, Springs of CA.

HOT SPRINGS. 133
apparently the place was not often visited. The water has no appre-
ciable taste or odor, but the large deposit of lime carbonate indicates
that it carries notable amounts of the constituents of that material.
The carbonate is deeply iron stained near the spring, so the water
probably contains also a fairly high amount of iron in solution.
The formation near the spring seems to be a terrace composed of
granitic bowlders and finer material. No direct evidence of the
origin of the springs was obtained, but as they lie along the eastern
front of the Sierra, where extensive faulting has taken place, it seems
probable that at this place, as at so many others, faulting has pro-
vided a means of escape for heated water.

WARM SPRINGS NEAR BRIDGEPORT (MONO 4).
About 1J miles south of Bridgeport are other hot springs that
have formed noteworthy deposits of lime carbonate. At this locality
there are about 20 pools, ranging in diameter from about 10 inches
to 10 yards, that are scattered for a distance of 350 yards along a
terrace that borders a small creek. Much gas, which is probably
carbon dioxide, rises; but the total visible flow of the springs is
only about 25 gallons a minute. Temperatures of 70° to 105° were
observed in the various pools. In addition to the present pools
there are a number of low mounds that are evidently extinct springs.
In 1908 the springs at this place were unused, and apparently had
not at any time been improved for bathing or other purposes.
The slopes that rise eastward are covered with lava that is probably
andesite. In a canyon half a mile eastward clifis of light-colored
siliceous tuff are exposed.

HOT SPRINGS NEAR BRIDGEPORT (MONO 3).
A much more noteworthy group of hot springs, similar in char-
acter to those just described, is found about 1| miles southeast
from Bridgeport, on hilly slopes of andesitic lava, 200 to 300 feet
above the valley. The locality of special interest is an area of gently
sloping ground, approximately 350 yards in diameter, that lies at the
base of steeper slopes and includes a number of prominent ridges of
banded onyx marble or travertine,1 5 to 15 feet high and of somewhat
greater thicknesses, that tend to radiate from a central point, as shown
in figure 3 (p. 134). Each of the better-developed ridges is cut longi-
tudinally by a vertical crevice, and the banding of the travertine,
which is stained various shades of red and yellow, is seen at several
places to be also vertical. On the outside of several of the ridges dull-
brown lime carbonate has formed but in nearly horizontal layers. It
has apparently been deposited where the water has flowed out over

1 Specimens of this material have been examined microscopically by E. S. Larsen, jr., and identified as
calcite.