USGS Topo Maps in Google Maps Gallery
Over 193,000 Topo Maps georeferenced in a seamless USGS Layer with a transparency control on the left.
See the Maps
http://maps.google.com/gallery/details?id=z4f-ZuCLmiKg.kUOos96GzVzs&hl=en
source:
http://googleenterprise.blogspot.com/2014/03/us-geological-survey-and-google-maps.html
Over 193,000 Topo Maps georeferenced in a seamless USGS Layer with a transparency control on the left.
See the Maps
http://maps.google.com/gallery/details?id=z4f-ZuCLmiKg.kUOos96GzVzs&hl=en
source:
http://googleenterprise.blogspot.com/2014/03/us-geological-survey-and-google-maps.html