Gibbon Falls on Gibbon River. Yellowstone National Park, Wyoming. 1970.

Album caption and index card: Gibbon Falls on Gibbon River. The river tumbles over a scarp etched in the Yellowstone Tuff. The scarp first formed along faults at the north edge of the Yellwostone caldera 600,000 years ago, at a point that now lies 1/4 to 1/2 mile downstream. Continued erosion has caused the falls to recede northward to their present position. Yellowstone National Park, Wyoming. 1970. Published as Figure 40-C in U.S. Geological Survey. Bulletin 1347. 1971.