Stratigraphic unit information is modified from the USGS GeoLex (Lexicon of Geology): http://ngmdb.usgs.gov/Geolex/geolex_qs.html.
A generalized geologic time scale is available at: http://3dparks.wr.usgs.gov/coloradoplateau/timescale.htm.
U.S. Department of the Interior - U.S. Geological Survey - Geology Discipline Privacy statement -- General disclaimer -- Accessibility The URL of this page is: http://3dparks.wr.usgs.gov/coloradoplateau/cp_strat.htm Maintained by Webmaster, Menlo Park, CA Last modified: 6/22/2009