Location and History
This district is in southcentral Nevada County about six miles northeast of Dutch Flat. It includes the Remington Hill, Negro Jack Hill, and Liberty Hill areas. The district was hydraulicked from the middle 1850s through the 1870s, and Liberty Hill was worked again from around 1896 to 1915.
The total output is unknown, but it exceeds $1 million. Lindgren, in 1911, estimated that two million yards had been removed and 16 million remained at Liberty Hill and that 1.75 million yards had been removed and 6 million remained at Remington Hill. Other estimates of remaining gravel at Liberty Hill range from six to 10 million yards.
Geology
The deposits are in a southwest-trending Tertiary channel that joins the Dutch Flat channel. There is a lower well-cemented blue gravel that contains gabbro and serpentine boulders and yielded 18 to 23 cents a yd. An upper quartz-rich gravel is in places covered by heavy clay. Bedrock is slate of the Blue Canyon Formation (Carboniferous) and some serpentine.
Bibliography
Lindgren, Waldemar, 1900, Colfax folio, California: U.S. Geol. Survey Geol. Atlas of the U.S., folio 66, 10 pp.
Lindgren, Waldemar, 1911, Tertiary grovels of the Sierra Nevada: U.S. Geol. Survey Prof. Paper 73, pp. 146-147.
MacBoyle, Errol. 1919, Nevada County, Lowell Hill mining district: California Min. Bur. Rept. 16, pp. 30-33.
