Page 296 - 1915, Springs of CA.

276 SPRINGS OF CALIFORNIA.
content of hydrogen sulphide is much greater in the sample treated
with iodine than in the other, the much smaller amount of sulphate
indicates that there was a marked change in the concentration of the
water during the year that intervened between the collection of the
two samples. However, in the first samples there appears to have
been a considerable increase in the amount of sulphate in the water
on standing, and a decrease in the sulphides, a change that probably
somewhat alters the medicinal properties of the water. Although
sulphides were not reported in the analyses, the change that takes
place in the sulphur compounds when the water stands for a time is
believed to show that sulphides are present.
Considerable inflammable gas rises in several of the springs.
Analysis 1 of a sample of this gas indicates that it consists principally
of methane (marsh gas, CH4), with carbon dioxide (CO2), and
hydrogen sulphide (H2S).
A third of a mile north of El Pajaro Springs are two other springs, or
wells. One issues at the base of a steep hillside through a 12-inch casing.
A few bubbles of gas rise with the water and the surface of the pool that
surrounds the casing is covered with a film of oil. The spring yields
about 1^ gallons a minute of sulphureted water that becomes milky
by the time it reaches a watering trough 10 yards away. The other
spring is situated in meadowland, 300 yards northwest of the first.
It yields perhaps 8 gallons a minute of clear water that is not notice-
ably sulphureted. It has been piped to a near-by storage tank for
supplying cattle troughs.
The rock of this area is light-colored shale of Tertiary age. Oil is
obtained from wells a few miles to the northeast. The fault zone
along which the earthquake of April 18, 1906, took place passes
through the locality. The shale along the fault zone has been
crushed by the earth movements, and landslides have been caused by
the shocks. The issuance of gas and sulphur water along this zone
of shattered material, where escape for them has been furnished, is
noteworthy.
SULPHUR SPRING ON MISSION CREEK (MONTEREY 6).
About 12 miles west of north from Jolon post office, or 10 miles
from San Antonio Mission, there is a cool sulphur spring that has been
used to a slight extent as a drinking spring. It is not near a main
traveled road, however, and is not widely known. The spring appar-
ently issues from sedimentary materials, probably of Tertiary age,
that form the hills bordering the west side of Salinas Valley.
i Analysts, Riddell and McCreary, 1908.