From the site: "Geologic map of the Higginsport quadrangle, Ohio-Kentucky and part of the Russellville quadrangle, Mason County, Kentucky"
From the National Geologic Map Database site: "Geologic map of the west half of the Winston-Salem quadrangle, North Carolina, Virginia, and...
From the National Geologic Map Database site: "Geology of the Whitley City quadrangle, Kentucky and the Kentucky part of the Winfield quadrangle"
From the site: "The Geographic Information Retrieval and Analysis System (GIRAS) was developed in the mid 70s to put into digital form a number of...
USGS GIS data of the United States water resources maps, soil, hydrology, and weather. Contains multiple links to useful and informative websites.
From the site: "This dataset and the accompanying Data Series report was created to assist in analysis and interpretation of water-quality data...
From the site: "This map layer contains the shallowest principal aquifers of the conterminous United States, Hawaii, Puerto Rico, and the U.S....
