Subject
Colorado River (Colo.-Mexico)
14
United States Discovery and exploration
9
Grand Canyon (Ariz.)
3
Arizona Description and travel
2
California, Gulf of (Mexico)
2
Southwest, New Description and travel
2
Birds
1
Botany
1
Colorado River (Colo.-Mexico) Description and travel
1
Geology
1
Indians of North America
1
Natural history
1
Zuni River (N.M. and Ariz.)
1