Columbia subject headings:
Geology, Stratigraphic--Carboniferous.
Paleogeography.
Paleontology--Carboniferous.
Harvard subject headings:
Geology, Stratigraphic--Carboniferous
Paleogeography--North America.
Paleogeography.
Paleontology--Carboniferous
Princeton subject headings:
Geology, Stratigraphic--Carboniferous.
Paleogeography.
Paleontology--Carboniferous.