 
|
 |
Gold Districts of California
JAMESTOWN
Location. The Jamestown district is in western Tuolumne County. It consists of
that portion of the Mother Lode belt that extends from French Flat southeast through
Rawhide, Jamestown, Quartz Mountain, and the town of Stent to the vicinity of the Belcher
mine, a distance of about eight miles. It also has been called the "Jimtown"
district.
History. The streams and rich surface ores were first worked in the gold rush.
Jamestown was established in 1848 by Colonel George F. James, a lawyer. Hydraulic mining
began at Stent soon afterward, and the lode mines were active from the 1860s on. The
placers at nearby Campo Seco yielded $5.5 million and those at Jamestown $3 million. From
around 1890 to World War I lode mining was a major industry; in 1906 more than 300 stamps
were "dropping" in the various mills. There was some activity again during the
1920s and appreciable activity during the 1930s. There has been minor prospecting and
development work in recent years at a few of the mines. The value of the total output of
this district is estimated at more than $30 million.
Geology. In the north portion of the district, the deposits occur along a
northwest-striking contact with serpentine to the southwest and phyllite, slate, and
metaconglomerate to the northeast (fig. 16). In the central and south portion, the
deposits are at or near the contact between massive greenstones and slates on the west and
chlorite and amphibolite schist to the east. Latite of Tuolumne Table Mountain crosses the
belt north of Jamestown, and Tertiary gravel deposits underlie the latite in the vicinity
of the town of Rawhide and to the southwest. At Quartz Mountain the Mother Lode belt
swings from a northwest-southeast strike to almost due south.
Ore Deposits. Outcrops consist of massive quartz veins up to several tens of
feet in thickness, adjacent bodies of ankerite-quartz-mariposite rock which sometimes are
scores of feet thick, as well as bodies of mineralized schist and numerous parallel quartz
stringers. These deposits often contain abundant disseminated sulfides (as much as eight
to 10 percent of the total rock), which are mostly pyrite. The gold occurs in the native
state or with pyrite. Milling-grade ore usually averaged 1/7 to % ounce gold per ton, but
the ore shoots were large. The ore shoots had stoping lengths of as much as 400 feet or
more, and several veins were mined to inclined depths of several thousand feet. A number
of high-grade pockets have been found in this district. In places silver is abundant, and
tellurides have been encountered.
Mines. Alabama $150,000, Alameda, Anderson, App-Heslep $6.5 million, Belcher,
Crystalline $100,000, Defender, Dutch-Sweeney $3 million, Erin-go-bragh $282,000, Golden
Rule, Harvard $2 million to $3 million, Hitchcock, jumper $5 million, Mazeppa, New Era,
Nugget, Omega, Rappahannock, Rawhide $6 million, Santa Ysabel $1.5 million.
Excerpt from: Gold Districts of California, by: W.B. Clark, California
Department of Conservation, Division of Mines and Geology, Bulletin 193, 1970.
Return to Principal Gold Districts
|
|
