North Carolina, Hydrogeologic unit map of the Piedmont and Blue Ridge province of

Hydrogeologic unit map of the Piedmont and Blue Ridge province of North Carolina.Charles C. Daniels and R. A. Payne; US Geological Survey & NC Dept. of Environment, Health, & Natural Resources.-Scale: 1 1/2 = 10 mi.; 66x29. 1990. Includes key to symbols, list of references, and extensive text. Water Resources Investigations Report 90-4035.