Learn more about the geological history of the rocks around you! This colorful, educational map presents state/regional surface rock outcrop information?age, depositional environment, rock type, and names of formations. Includes major highways, towns, and landmarks. Printed on a single sheet and folded to glove compartment size, has a stratigraphic column by state, mileage charts. Scale: 1 inch=30 miles. Idaho, Montana, and Wyoming. Revised 1997.