Nevada City, the center of an important gold-mining district, is on the western slope of the Sierra Nevada at an altitude of 2500 feet, approximately 50 miles by airline north-northwest of Sacramento. It lies on the eastern edge of the Smartsville quadrangle (Lindgren and Turner, 1895) and gives its name to one of the three sheets of the Nevada City Special folio (Lindgren, 1896b), mapped on a scale of 1/14,400, or a little more than 4 inches to the mile. In addition to the two folios, Lindgren (1896a) published the classic report on the gold-quartz veins of Nevada City and its neighbor to the south, Grass Valley.
Since the publication of Lindgren’s report the mines of both districts have been greatly deepened and many miles of underground workings have been opened. In 1930 the United States Geological Survey undertook a resurvey of the Grass Valley district and assigned the . . .