Page 152 - 1915, Springs of CA.

140 SPBINGS OF CALIFOKNIA.
BUMPASS HOT SPRINGS (SHASTA 16).
Bumpass Hot Springs (PL X, C) are situated on the side of Lassen
Peak, about 9 miles by trail northward from Morgan Hot Springs
(Tehama2,p. 138). They consist of numerous pools of hot water, some
of them in vigorous ebullition and rendered turbid by mud, and others
less active but turbid with sulphur in suspension. Some pools con-
tain acid or astringent water which is usually turbid with clay. The
analysis given on page 142, with analyses of waterfrom Devils Kitchen
and Morgan Hot Springs, shows the composition of water from one
of the principal springs, which is noticeably acid and sulphureted.
The position of the vents and the activity of the discharge change
from time to time and seem to be influenced to a large extent by the
surface supply of water, for the springs themselves yield a relatively
small amount. In November, 1909, the stream running from them,
which is a branch of Milt Creek, carried perhaps 200 gallons a minute
at a time when the adjacent slopes were covered with snow. In the
following July it carried perhaps half as much, though melting
patches of snow still covered parts of the near-by slopes. On the
earlier date there was a pond 20 yards across, at whose edge was a
large vent, from which muddy water was being thrown to a height
of 10 feet, but in the summer this pond was nearly drained and the
active spring had subsided to a sputtering pool.
The area covered by the springs and vents of Bumpass Hot
Springs or Bumpass Hell, as it is locally called is only about 200
yards long and 100 yards wide, but the rock for some distance
surrounding the active area has been altered to a white, siliceous
material by acid water and solfataric vapors. About 300 yards
downstream from the main area there is an area perhaps 50 yards in
diameter where also the rock has been greatly altered. When visited
vapor still escaped from numerous small vents, and needles of sulphur
crystallized at their orifices, but no wa^ter was flowing from them.
The locality has been mapped geologically by Diller 1 as a small
area of basaltic lava at the lower border of dacite that overlies
pyroxene andesite. The small basaltic area appears to have been
intruded through these earlier lavas that form the greater part of
Lassen Peak.
In 1910 the springs were occasionally visited as a natural curiosity,
but the mineralized waters were not used for bathing or for other
purposes. The Lassen Peak region is rapidly becoming a summer
vacation ground, however, both because of the excellent fishing in its
numerous streams and small lakes and because of its scenic features,
and Bumpass Hot Springs will probably become a favorite objective
J DiUer, J. S., U. S. Geol. Survey Geol. Atlas, Lassen Peak folio (No. 15), 1895.