Subject
United States Discovery and exploration
11
Southwest, New Description and travel
4
Colorado River (Colo.-Mexico)
2
Dakota Territory Description and travel
2
Geology
2
Natural history
2
Nebraska Description and travel
2
West (U.S.) Description and travel
2
Birds
1
Botany
1
California, Gulf of (Mexico)
1
Canadian River
1
Great Plains Description and travel
1
Great Salt Lake (Utah)
1
Indians of North America
1
Mexico Boundaries
1
Military roads
1
Minnesota Description and travel
1
Red River Valley (Minn. and N.D.-Man.)
1
Texas Description and travel
1
United States Boundaries
1