Geologic Provinces of the United States: Interior Plain Province
http://geomaps.wr.usgs.gov/parks/province/intplain.html

USGS: Western Region Geologic Information


This USGS site provides an overview of the geologic history of the interior plains province. External links lead to information about national parks that exhibit interior plains geology and similar overviews of other physiographic provinces. An image gallery and additional maps and illustrations are also provided.

This resource is referenced here:
Subject: Geoscience:Geology:Historical Geology, Geomorphology, Geography:Physical
Resource Type: Scientific Resources:Overview/Reference Work
Topics: Time/Earth History, Solid Earth, Earth surface