Columbia subject headings:
Geology, Stratigraphic.
Paleogeography--Canada.
Paleogeography--North America.
Reefs--Canada.
Reefs--North America.
Harvard subject headings:
Reefs--Canada.
Princeton subject headings:
Geology, Stratigraphic.
Paleogeography--Canada.
Paleogeography--North America.
Reefs--Canada.
Reefs--North America.