Dr. Theodore Comstock's important geological map was one of the first ever drawn of the Yellowstone - Uinta area. He was the geologist with Capt. W.A. Jones' military reconnaissance of northwestern Wyoming. The map is very colorful with 15 colors designating the various geological features. Ref: W. Goetzman, Exploration and Empire, pp 709-12. Folded as issued with only a bit of faint toning.