Near the line of San Bernardino and San Diego Counties, about 5 to 8
miles west from the town of Perris, are the mines of the Pinacate
District, all being veins of quartz-bearing gold. In past years this
district has produced a large amount of bullion, the quartz being worked
in arrastras, the beds of over a hundred of which still may be seen
scattered about.
There are numerous springs of small size in the district, but timber is
very scarce. The formation is syenite and granite principally;
occasionally schistose and gneissoid rocks and quartzites being
observed. The entire region is metamorphic, excepting a few dikes of
granite (pegmatite) and quartz porphyry. Diorite is found near the Good
Hope Mine. The region is one easily accessible, and but 4 to 8 miles
from a railroad.