Explorer John Wesley Powell (center, with fellow geologists at Harper’s Ferry in 1897) set out on many expeditions throughout the great Western Frontier. (U.S. Geological Survey Photographic Library)
U.S. Geological Survey Photographic Library
Explorer John Wesley Powell (center, with fellow geologists at Harper’s Ferry in 1897) set out on many expeditions throughout the great Western Frontier. (U.S. Geological Survey Photographic Library)
U.S. Geological Survey Photographic Library