ris" or "anti-slickins" fight ended in
favour of the farmers. In 1893 the United States government created a
California Debris Commission, which has acted in unison with the state
authorities. Permits for hydraulic mining are granted by the commission
only when all gravel is satisfactorily impounded and no harm is done to
the streams; and the improvement of these, which was impossible so long
as limits were not set to hydraulic mining, can now be effectively
advanced. Quartz mining began as early as 1851. In 1908 about
five-eighths of the gold output was from such mines. Quartz veins are
very often as good at a depth of 3000 ft. as at the surface. A
remarkable feature of recent years (especially since 1900) is gold
"dredging." Thousands of acres even of orchard, vineyard and farming
land have been thus treated in recent years. Gold was being produced in
1906 in more than thirty counties. The annual output since 1875 has been
about $15,000,000 to $17,000,000; in 1905, according to the Mines
Report, it was $18,898,545. Colorado now excels California as a gold
producer.

_Mineral Products._--California produces more than forty mineral
substances that are of commercial significance. Gold, petroleum, copper,
borax and its products, clays, quicksilver and silver lead, in order of
importance, representing some four-fifths of the total. From 1894 to
1902 the aggregate production increased from 20.2 to 35.1 million
dollars; in 1908 it was $65,137,636. Metallic products long represented
three-fourths of the total, but the feature of recent years has been the
rising importance of hydrocarbons and gases, and of structural
materials, and indeed of non-metallic products generally. The production
of crude petroleum has grown very rapidly since about 1895. Oil is found
from north to south over some 600 m., but especially in Southern
California. The high cost of coal, which has always been a hindrance to
the development of manufactures, makes the petroleum deposits of
peculiar value. Their total output increased from 4,250,000 to
44,854,737 barrels between 1900 and 1908, and the value of the product
in 1908 was $23,433,502. The Kern river field is the most important in
the state and one of the greatest in the world. Those of Coalinga, Santa
Maria and Lompoc, and Los Angeles are next in importance. Both in 1900
and in 1905 California ranked fifth among the states of the United
States in the petroleum refining industry. Copper has risen i