text ub Reston, VA U.S Dept. of the Interior, U.S. Geological Survey 1991 monographic 8.p maps 23cm Cover Tittle United States http://catalog.gpo.gov/fdlpdir/locate.jsp?ItemNumber=621&SYS=000362755 http://catalog.gpo.gov/fdlpdir/locate.jsp?ItemNumber=621&SYS=000362755 GPO 920114 20170215094853.0 000362755