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Geologic map of the Duncan Peak and southern part of the Cisco Grove 7 1/2' quadrangles, Placer and Nevada Counties, California

This map covers an area of 123 km2 on the west slope of the Sierra Nevada, an uplifted and west-tilted range in eastern California (fig. 1). The area is located 20 km west of Donner Pass, which lies on the east escarpment of the range, and about 80 km east of the Great Valley Province. Interstate Highway 80 is the major route over the range at this latitude and secondary roads, which spur of