editors Sheila Roberts, Don Winston ; prepared and published by the University of Montana, Missoula ; Western Montana College of the University of Montana, Dillon
by Omer B. Raup ... [and others] ; photography by Omer B. Raup ; pen and ink drawings by Arthur L. Isom and Omer B. Raup ; prepared by the U.S. Geological Survey in cooperation with the National Park Service