Columbia subject headings:
Canada--Colonization.
Canada--Historical geography.
Clark, Andrew Hill, 1911-1975.
United States--Colonization.
United States--Historical geography.
Harvard subject headings:
Canada--Colonization.
Canada--Historical geography.
Clark, Andrew Hill, 1911-1975
United States--Colonization.
United States--Historical geography.
Princeton subject headings:
Canada--Colonization.
Canada--Historical geography.
Clark, Andrew Hill, 1911-1975.
United States--Colonization.
United States--Historical geography.