EXPLANATION OF PLATES. 
Pirate 1. Map of the Black Hills area showing present distribution of 
gravels, possible sources of pebbles, and possible routes of 
pebbles from sources to localities where found. 
Topographie map of the Black Hills area. 
Map showing altitudes indicated by aneroid barometer. 
Topographic map of the Bighorn area. The Red Canyon joins: 
Big Goose Creek from the south near the center of the map. 
