Columbia subject headings:
Harvard subject headings:
Human beings--Effect of climate on--North America.
Indians of North America--Antiquities.
North America--Antiquities
Paleoclimatology--North America.
Paleoecology--North America.
Princeton subject headings:
Grasslands--North America.
Human beings--Effect of climate on--North America.
Paleo-Indians--North America.
Paleoclimatology--North America.