Interactive Geologic Index Map of Washington

While poking around on the Internet, I came across an interactive geologic index map of Washington that may be of use to prospectors.

Called the Washington State Geology Index Map by creator Christopher Heg (whose homepage is here), the map features click-able quadrangles measuring 1 degree of longitude by 30 minutes of latitude which lead to a detailed geologic map of that area.  On the geologic map, each rock type is shown in color.  By clicking on a color, an information bar at the top of the page displays the color, symbol, era, lithology, and named unit or note about the formation.  There are also buttons at the top of the map page to toggle between the geologic map and a color aerial photo of the same area.  In addition, main cities and highways are labeled on both views.

Check out the link above (or in the right-hand sidebar under Resources for Prospectors/MAPPING APPLICATIONS & ONLINE SPATIAL DATA) to explore for yourself.