This placer-mining district is in north-central Nevada County. The North Columbia district adjoins it on the east and the North San Juan district on the west. It was hydraulicked extensively from the 1850s through the 1880s. Later, Chinese miners reworked the tailings. It includes the Cherokee diggings. This district was recently studied by the U.S. Bureau of Mines and U.S. Geological Survey as part of their heavy metals programs.
The deposits are part of the Tertiary North Bloomfield-North Columbia-North San Juan channel. The gravels are thick, the lower part being quartzitic and the upper part containing abundant sand and clay. The lower gravels were rich. The upper gravels yielded 10 to 15 cents per yard. Bedrock is slate and phyllite, with granodiorite lying to the west. The value of the total output for the district is unknown, but it has been estimated at several million dollars. In 1891 the U.S. Army Engineers estimated that 10 million yards had been excavated and 33 million remained.
lindgren, Waldemar, 1911, Tertiary gravels of the Sierra Nevada: U.S. Geol. Survey Prof. Paper 73, pp. 121-130.
lindgren, Waldemar, and Turner, H. W., 1895, Smartsville folio, California: U. S. Geol. Survey Geol. Atlas of the U. S., folio 18, 6 pp.