Page 150 - 1915, Springs of CA.

138 SPRINGS OF CALIFORNIA,

exposed at places near the base of the slopes. The small ridge at
whose end the main spring rises is of dioritic material.
Like many other ranges of this region, the Black Mountains appear
to be a faulted block that dips eastward. Saratoga Springs rise at a
point along this block where the intrusive dioritic rock has possibly
produced conditions that permit the escape of water from a moderate
depth. It does not seem probable that this spring is supplied either
by water from the sink of Amargosa River or by deep alluvial water
that may here be brought to the surface, for the surface slope, the
temperature of the water, and its freshness compared with the water
of Amargosa River do not favor either source.
MORGAN HOT SPRINGS (TEHAMA 2).
In the neighborhood of Lassen Peak, in the northeastern part of the
State, there are some remarkable hot springs, whose positions with
respect to each other and the peak are shown on Plate XI 1 (p. 140).
The best-known group is at the southern base of the mountain on the
Morgan ranch, where about 25 springs and pools are scattered for a
distance of 600 yards in a meadow along Mill Creek. Most of them
are quiet pools of small flow, less than 5 feet in diameter and relatively
shallow. A number of them contain thick algous growths, and
several deposit native sulphur. Others rise in areas where hard
deposits of siliceous and of calcareous materials have formed. Three
or four springs steam and sputter from vents on the banks of the
creek. One of the northernmost of these springs seems to have a
true geyser action, for it issues in a shallow basin 3 feet in diameter
in which the water is said to come to a state of vigorous ebullition
and then to subside about once a day. During a period of 41 hours
the condition of this spring was noted five times as follows: At the
beginning of the period, in active ebullition, discharge about 15
gallons a minute, temperature 200° + ; two hours later quiet, no
overflow, temperature 187°; at 16 hours and at 25 hours later in
active ebullition, overflowing; at 41 hours, quietly overflowing, about
5 gallons a minute.
The place has been a camping resort for a number of years. In
1910 there were log bathhouses at three springs, a small shed over
another pool, and a vapor bathhouse over a vent at the creek edge.
An analysis (tabulated on p. 142), of water from one of two pools,
about 3 feet in diameter, in an area of hard siliceous deposit 45 yards
west of the creek edge and 50 yards north of the eastern log bath-
i The descriptions of hot springs in the Lassen Peak region apply to conditions during 1909-10. The
conditions vary from time to time and possibly were considerably changed by the renewed activity of
the peak in 1914. The mountain, which had been considered an extinct volcano, broke forth on May 30,
1914, in eruptions that appear to have been volcanic, not geyser-like, and at intervals vapors, volcanic
dust, and stones were cast out from two small craters developed near the summit.