Page 73 - 1915, Springs of CA.

HOT SPRINGS. 69

Analysis of water from Newsoms Arroyo Grande Warm Spring, San Luis Obispo
County, Cal.
[Analyst and authority, Winslow Anderson (1888). Constituents are in parts per million.]
38° C. (100° F.)
Properties of reaction:
Primary salinity ................................................................ 34
3
0
Primary alkalinity 0
63
Tertiary alkalinity .............................................................. 86
By Reacting
Constituents. weight. values.

Sodium (Na) ....................................................................... 62 2.70
Potassium (K). ..................................................................... 24 .61
Calcium (Ca)....................................... ................................ 60 3.01
Magnesium (Mg). ................................................................... 40 3.30
Iron (Fe)..... ...................................................................... 33 1.18
3 .33
Sulphate (&&$....... .............................................................. 116 2.41
CMorite(Cl)........ ................................................................ 43 1.20
Carbonate (CO3).... ................................................................ 216 7.19
Silica (Si02).................................................... .................... 35 1.10
632
Carbon dioxide (CO%). .................. ................................ ....'........ 127 5.76
Hydrogen sulphide (B^S).. ....................... .................................. 23 1.38
The water of this spring is secondary alkaline and primary saline
in character, tertiary alkalinity being also an important characteristic.
The property has been open to the public as a resort since 1864.
In 1908 there were accommodations for about 30 people in a hotel
building and small cottages. The baths have been much patronized
on Sundays by people from Arroyo Grande, and the water has been
carbonated and bottled by the local soda works.
The siliceous shales that form the hills of this locality have been
steeply uplifted and exhibit dips which show that the structure here
is disturbed, and indicate that the spring probably rises along frac-
tures produced at a zone of sharp change in the inclination of the
beds.
PECHO WARM SPRINGS (SAN LUIS OBISPO 7).
In the canyon of Islay Creek, west of San Luis Obispo, and about
2 miles from the coast, are two warm, disagreeably sulphureted springs
which are known as Pecho Warm Springs. When visited in 1908
there was a wooden trough tub and a screen of gunny sacking at the
larger spring, while the other was used only as a drinking pool.
Their observed temperatures were 95° and 72° and their flows, respec-
tively, about 15 gallons and 2 gallons a minute. The larger spring
issues at the creek edge, at the base of a 10-foot bank of crushed
shale, the other rises about 150 yards farther downstream, and at the
roadside 10 yards from the creek.
The hills of this vicinity are composed of shales of Miocene age,
in which the structure indicates that there has been sufficient local
folding and crushing to account for the existence and temperature
of the springs.