Geology
The district is underlain by a series of northwest-striking beds of phyllite, amphibolite, green schist, and serpentine. Widespread hydrothermal alteration has changed much of the serpentine to extensive bodies of mariposite-ankerite-quartz rock. Slate of the Mariposa Formation (Upper Jurassic) lies to the west and metasediments of the Calaveras Formation (Carboniferous to Permian) to the east.
Ore deposits
The deposits consist of thick, massive, and often barren quartz veins, with adjacent large bodies of auriferous schist and pyritic ankeritemariposite-quartz rock containing numerous thin quartz seams and stringers. Milling ore usually was low in grade, but the ore bodies were extensive. The famous Hanging Wall ore body, which consisted of auriferous schist, averaged 1/2 ounce of gold per ton and had dimensions of 175 x 4500 x 15 feet. Much rich high-grade ore from surface pockets was recovered in the 1850s. Tellurides, which included calaverite, sylvanite, hessite, and petzite, were recovered in quantity during the early days, near the surface. Both calaverite and melonite, a rare nickel telluride, were first found and described from this district.
Mines
Carson Hill Mines $26 million (Calaveras, Finnegan, Melones, Morgan, Reserve, Stanislaus Mines), Carson Creek $1 million, Hardy, Santa Ana, Tulloch.
Bibliography
Burgess, John A" 1937, Mining methods at the Carson Hill mine, Calaveras County, California: U. S. Bur. Mines Inf. Circ. 6940, 15 pp.
Clark, W. B., and Lydon, P. A., 1962, Calaveras County, Carson Hill mines: California Div. Mines and Geology, County Rept. 2, pp. 44-50.
Erie, J. H., Stromquist, A. A., and Swinney, C. M., 1955, Geology and mineral deposits of the Angels Camp and Sonara quadrangles, Calaveras and Tuolumne Counties, California: California Div. Mines Spec. Rept. 41, 55 pp.
Knopf, Adolph, 1929, Mines on Carson Hill: U. S. Geol. Survey Prof. Paper 157, pp. 72-77.
Logan, C. A., 1935, Carson Hill mines: California Div. Mines Bull. 108, pp. 129-137.
Moss, F. A., 1927, The geology of Carson Hill: Eng. and Min. Jour., vol. 124, no. 26, pp. 1010-1012.
Ransome, F. lo, 1900, Mother lode district folio: U. S. Geol. Survey Atlas of the U.S., folio 63, 11 pp.
Storms, W. H., 1900, Melones Consolidated mines: California Min. Bur. Bull. 18, pp. 121-122.
Turner, H. W., 1894, Jackson folio, California: U. S. Geol. Survey Geol. Atlas of the U.S., folio 11, 6 pp.
Young, G. J., 1921, Gold mining at Carson Hill: Eng. and Min. Jour., vol. 112, pp. 725-729.
