Columbia subject headings:
Harvard subject headings:
Geology, Stratigraphic--Paleozoic--Congresses
Geology--West (U.S.)--Congresses.
Paleogeography--West (U.S.)--Congresses.
Princeton subject headings:
Geology, Stratigraphic--Paleozoic--Congresses.
Geology--Rocky Mountains--Congresses.
Paleogeography--Rocky Mountains--Congresses.