Blue Tent is northeast of the Nevada City district in western Nevada County. The area was mined years ago by hydraulicking, but little or no mining has been done since. The gravels are part of the Tertiary channel that extends north-northwest from You Bet through Scotts Flat and Quaker Hill to North Columbia. Although the gravels here are extensive, they were reported not to have been very remunerative. Lindgren (1911) estimated that 15 million cubic yards had been removed and 90 million yards remain, much of it barren clay and sand. The gravel next to bedrock was reported to have yielded about SO cents in gold per yard. To the east and south the gravels are overlain by andesite. Bedrock is phyllite and slate.
Lindgren, Waldemar, 1911, Tertiary gravels of the Sierra Nevada: U.S. Geol. Survey Prof. Paper 73, p. 143.
Lindgren, Waldemar, 1900, Colfax folio: U. S. Geol. Survey Geol. Atlas of the U. S., folio 66, 10 pp.