New Idaho Geological Map

LEWISTON, Idaho (AP) — The Idaho Geological Survey is releasing its first new geologic map of the state since 1978. The Lewiston Tribune reports that the 36-by48-inch map goes on sale Friday for $20. Idaho Geological Survey Director Roy Breckenridge calls the map a piece of art. It's a shaded relief map that uses 75 colors to identify geological formations, different varieties of rocks and their ages. The Lake Missoula and Lake Bonneville flood deposits are identified on the map, for example. Breckenridge says Idaho rocks haven't changed much since the 1978 map, but a lot of new mapping has been done that adds new information to the most recent map. He says technology has also increased the ability to date rocks, making the map more accurate in dating geologic formations.