Page 163 - 1915, Springs of CA.

HOT SPRINGS. 147
At the base of hills a quarter of a mile northeastward is a shal-
low circular basin in the volcanic soil and gravel. In 1908 no
water or noticeable amount of vapor issued here, but at four
places the ground was hot. An Indian 50 or 60 years old, who was
met at the springs, volunteered the information that this basin was
formerly more active, and he described in graphic manner the rum-
bling that years ago was heard here. The rumbling of the present
springs is occasionally heard at a distance of several miles, especially
during cold weather.
CASA DIABLO HOT POOL (MONO 16).
About 3| miles east of Casa Diablo Hot Springs there is a shallow
pool, measuring about 30 by 35 yards, which may be called Casa
Diablo Hot Pool. In November, 1908, this pool was not over-
flowing, though there was a small, well-defined outlet channel from
it toward Hot Creek. Over nearly its entire bottom were numerous
vents in which water bubbled and in several of which, near the margin,
temperatures of 120° to 180° were recorded. Near the western bor-
der of the pool there are small amounts of soda alkali and also a little
alum, and along part of the overflow channel there is a hard deposit,
apparently of silica and lime carbonate, which also covers an area
about 50 yards in diameter near the drainage channel. Its formation
indicates that a portion of the bubbles that rise in the pool are of
carbon dioxide rather than of steam. The pool is situated at the base
of a small lava bluff that trends northward along the hillside and that
has the appearance of a small fault scarp, but it may be only a small
persistent scarp of erosion.

HOT SPRING NORTHEAST OF CASA DIABLO HOT SPRINGS (MONO 14).
About 5 miles northeast of Casa Diablo Hot Springs there is a
pool, apparently of considerable depth, in which the water has a
scalding temperature and is mildly sulphureted. It is not so active
as the more southern springs, though it is similar to them in character.
Like the Casa Diablo Hot Springs and Hot Pool, it is situated at the
eastern front of the Sierra, in an area covered by comparatively
recent lava, and both its position and its activity suggest that,
like the springs in the Lassen Peak region, its heat is derived mainly
from underlying lava and that places for the surface escape of the
water may be furnished by faulting.
WARM SPRINGS IN LONG VALLEY (MONO 17).
In Long Valley, 3 miles west of Owens River and about 7 miles
south of east of Casa Diablo Springs, there are two oblong pools
a few feet apart and 40 feet long in which warm water rises and from
which it flows to a shallow pond called Whitmore Tub. A niaxi-