Vallecito is in south-central Calaveras County about five miles east of Angels Camp and five miles south of Murphys. It a placer-mining district and includes the Douglas Flat and Dead Horse Flat areas.
Daniel and John Murphy found gold here in 1848, and the district was first known as Murphys' Old Diggins. The name was changed to Vallecito in 1854. The hydraulic mines were active from the late 1850s through the 1880s. Drift mining was done at this time and again during the 1930s, when the Vallecito Western drift mine was operated on a fairly large scale. Dragline dredging was active in the district during the 1930s.
The Tertiary Central Hill channel enrers the district from the north from Murphys and then extends west toward Altaville and Angels Camp. Here the channel is joined by two small tributaries from the east and south, the one from the east known as the Murphy's Gulch channel. Farther east is the south-trending Cataract channel. The gravels, consisting of granitic material and quartz, were richest near bedrock. The gold was fairly coarse. The gravels are overlain in places by rhyolite and andesite and also by some Pleistocene gravels. Bedrock is limestone, schist, slate, and amphibolite, and to the west there is granodiorite.
Clarle, W. B., and Lydon, P. A., 1962. Calayeral County, gold: California Diy. Mines and Geology County Rept. 2, pp. 32-93.
Lindgren, Waldemar, 1911, Tertiary gravel of the Sierra Nevada: U.S. Geol. Suryey Prof. Paper 73. pp. 199-201.
Logan. C. A., and Franke, H., 1936, Calaveras County, Vollecito-Western mine: California Div. Mines Rept. 32, pp. 353-355.
Stefia, Donald, 1932. Gold mining and milling methods and costs at the Vallecito Western drift mine: U.S. Bur. Mine Inf. Circ. 6612, 13 pp.
Storms, W. H., 1894. Ancient channel syltem of Calayeras County: California Min. Bur. Rept. 12. pp. 482-492.
Turner, H.W. and Ransome. F. L., 1B98. Big Trees folio: U.S. Geol. Survey Geol. Atlals of the U.S., folio 51, 8 pp.