Page 84 - 1915, Springs of CA.

80 SPRINGS OF CALIFORNIA.
The large amount of magnesium in proportion to calcium is worthy
of note in connection with the presence of serpentine in the locality.
This is a primary-saline water in which secondary salinity is a
.notable property. Tertiary alkalinity is also high, adding to its
medicinal value.
The spring has been used* as a resort since the seventies, and in
1908 a hotel, annex, and cottages provided rooms for about 125
guests. From a cemented and covered reservoir that has been exca-
vated at the spring the water flows into two small plunge baths and is
also piped to bathtubs. Besides its use for bathing, the water is
much used for drinking and has been carbonated and bottled for a
number of years by the soda works at Gilroy.
WARM SPRINGS (ALAMEDA 3).
Four warm springs that issue on the hillside bordering the lowland
at the southeast end of San Francisco Bay have given the small
town of Warm Springs its name. They are situated about 2 miles
northeast of the town, within the private grounds of Mr. Joseph W.
Stanford. One of the springs rises in the lawn adjacent to Mr. Stan-
ford's residence. It has been inclosed to form a covered reservoir
about 12 feet square, which furnishes part of the domestic supply
and yields perhaps 5 gallons a minute. Two other springs rise
beside a walk a few yards away, in open basins, from which there
are flows of approximately 1 and 4 gallons. The larger of these two
springs has a temperature of 86°. The fourth spring is 200 yards
southward, in a little swale on the southern side of a knoll. It yields
perhaps 5 gallons a minute, of water 90° in temperature, which is
collected in a small covered reservoir and piped to the grounds for
domestic and garden use.
The water of all the springs is faintly sulphureted and is considered
to ,be somewhat mineralized by sodium salts.
Sandstone, gravel, and some calcareous material form the hill slopes
here. A fault is mapped on Plate III (in pocket) along these slopes;
and a landslide scar some distance above the springs, and other, cooler
springs on the higher slopes furnish local evidence that faulting has
taken place and has probably given rise to the warm springs. At the
tune of the earthquake in April, 1906, a fifth small spring broke forth
in the lawn near the residence and flowed for a month.

ROCKY POINT SPUING (MARIN 3).
In the Coast Ranges north of San Francisco Bay are a number
of thermal springs that form a general group in the older sediments
of this part of the State. A warm spring that is mildly sulphureted
rises on the beach about 6 miles northwest of Point Bonita. It is
locally known as Rocky Point Spring, but it is exposed only at low