Geologic Map Day
http://www.earthsciweek.org/geologicmap/
The prettiest information resources: Geologic maps
Information Culture, Scientific American by Bonnie
Swoger, October 18, 2013, http://blogs.scientificamerican.com/information-culture/2013/10/18/the-prettiest-information-resources-geologic-maps/
Digital geologic maps of US States
http://mrdata.usgs.gov/geology/state/
Database of the Geologic Map of North America—
adapted from the Map by J.C. Reed, Jr. and others
(2005), U.S. Geological Survey Data Series 424
http://pubs.usgs.gov/ds/424/
OneGeology Portal – Geologic map of the world
http://portal.onegeology.org/
Not geological Maps, but still useful collection of
historical topographic maps, which can be
downloaded as GeoPDFs
http://ngmdb.usgs.gov/maps/TopoView/
Yours,
Paul H.
