Columbia subject headings:
Natural history--United States.
Naturalists--Correspondence.
United States--Description and travel.
Harvard subject headings:
Bartram, John, 1699-1777--Travel--East (U.S.)
Bartram, William, 1739-1823--Travel--East (U.S.)
Botanists--Pennsylvania--Biography.
East (U.S.)--Description and travel.
Natural history--East (U.S.)
Natural history--United States
Naturalists--Biography
Naturalists--Pennsylvania--Biography.
Naturalists--United States--Biography
Naturalists--United States--Correspondence
United States--Description and travel.
Princeton subject headings:
Natural history--United States.
Naturalists--Correspondence.
United States--Description and travel.