From Pt. Lookout N. down Canyon to River, 1200 Feet below. Yellowstone Nat. Park, Wyo.

GRAND CANYON. The scene before us, with the diagram below, explains the origin of Yellowstone Park in volcanic action which partly filled this valley with lava and scoria. These also illustrate how the Yellowstone River, during pergaps a million years, has cut its way down through the rim of the volcanic plateau. The vast extent of the volcanic deposits rener plausible the theory that through long ages enough internal heat has been retained to account for the present geysers and hot springs. (View looking E. Elev. [canyon rim] abt. 7,500 ft. Lat. 45° N.; Long. 111° W.)