Page 122 - 1915, Springs of CA.

114 SPRINGS OF CALIFORNIA.

tively high proportion of silica in the first two is noteworthy. It
is not unlikely that the third also is characterized by a high proportion
of silica, and that a typographical error in the analytical statement
is responsible for its apparently low silica content.
FETTERS HOT SPRINGS (SONOMA 19).
During the summer of 1909 a bathing establishment which is sup-
plied by four drilled wells was erected about 200 yards east of the
Agua Caliente baths. A hotel was opened on the grounds and the
place was advertised in 1910 as Eleda Hot Springs, but it has since
become known as Fetters Hot Springs (PL VII, O, p. 108).
The hills that border the eastern side of Sonoma Valley are of rhyo-
litic lava, and the wells at the several resorts are drilled into volcanic
tuff that underlies the thin layer of alluvium in this part of the valley.
The presence of the lava, which is thought to be of a relatively recent
geologic period of effusion, suggests that a rather high temperature
gradient accounts for the thermal character of the waters and that
the structure probably furnishes the artesian conditions.
WARM SPRINGS OF STATE HOME AT ELDRIDGE (SONOMA 16).
Warm springs that seem to be similar in origin to the artesian
waters of the resorts just described issue at several points north of
Sonoma Valley. At the vegetable and dairy farm of the State Home
at Eldridge water 72° in temperature is obtained from a spring that
yields about 10 gallons a minute of water that is used in the dairy
and for irrigation. The water broke forth at this spring at the time
of the earth'quake of April 18, 1906, and a flowing well 50 yards north-
ward ceased to flow. A light-colored tuffaceous rock is exposed a few
yards from the spring.

LOS GUILICOS WARM SPRINGS (SONOMA 15).
On the banks of Sonoma Creek, about 1£ miles southwest of Ken-
wood are two springs which yield, respectively, about 2 and 3 gallons
a minute of water at temperatures of 78° and 82°. In 1909 there
was a small bathing pool and an old hall or pavilion at the spring near
the eastern bank of the creek; at the other spring, on the opposite
bank, there was a small pool inclosed by an old bathhouse. The
place was used as a camping resort, and several cottages had been
erected among the trees near by.

WARM SPRINGS ON McEWAN RANCH (SONOMA 14).
Large warm springs that are probably similar in origin to the Los
Guilicos springs and others farther south, issue on the McEwan ranch,
about 1J miles west of Los Guilicos Warm Springs. A part of their