United States Geological Survey
http://www.usgs.gov
Includes fact sheets and maps for every U.S. state, with both geological and biological information. Also includes a publication search, photofinder, geographic names index, and much more.

American Geological Institute
http://www.agiweb.org
Access to the National Geoscience Data Repository System, earth science newsletters, databases, and AGI publications. See the links on the top left side of the page.

SciQuest SciCentral
http://www.sciquest.com/cgi-bin/ncommerce3/
ExecMacro/sci_sitemap.d2w/report?nav_banner=special=39186
News and articles on biological sciences, physical sciences, earth sciences, engineering sciences, and more.