Preliminary Integrated Geologic Map Databases for the United States
The growth in the use of Geographic Information Systems (GIS) has highlighted the need for regional and national digital geologic maps that have been attributed with information about age and lithology.
Ludington, S., B.C. Moring, R.J. Miller, P.A. Stone, A.A. Bookstrom, D.R. Bedford, J.G. Evans, G.A. Haxel, C.J. Nutt, K.S. Flyn, and M.J. Hopkins. 2007. Preliminary integrated geologic map databases for the United States. Western States: California, Nevada, Arizona, Washington, Oregon, Idaho, and Utah. Version 1.3. USGS Open-File Report (2005-1305). Available at: Preliminary integrated geologic map databases for the United States. Accessed January 5, 2019.