Geology of the conterminous United States at 1:2,500,000 scale [electronic resource] : a digital representation of the 1974 P.B. King and H.M. Beikman map / U.S. Department of the Interior, U.S. Geological Survey ; by Paul G. Schruben, Raymond E. Arndt, and Walter J. Bawiec ; display software by Russell A. Ambroziak.
Reston, VA : The Survey ; Denver, CO : For sale by USGS Map Distribution, 1998.
Menu-driven digital version of King and Beikman's 1974 map, with searchable copy of the text and figures from Professional Paper 901 describing map's historical background and limitations. Data provided in U.S. Geological Survey Mapper for DOS, ARC/INFO version 6.1.1 Export, Digital Line Graph (DLG) Optional, Map Overlay Statistical System (MOSS), and Drawing Exchange File (DXF) formats.