WSGS offers free download of Geological Map of Wyoming
August 7, 2014

If you prefer, the map is available for purchase for $25.00.
The map is very detailed and rather large at 50Mb, so a little patience is necessary if you click on the link. Also, be sure to download both portions -- the legend is a separate 9Mb file.
Download Online Version from WSGS
Order Printed Version from WSGS