Columbia subject headings:
Geology, Stratigraphic--Paleozoic.
Geology--Africa, Southern.
Geology--Antarctica.
Geology--Middle East.
Harvard subject headings:
Geology, Stratigraphic--Paleozoic
Geology--Africa, Southern.
Geology--Antarctica
Geology--Middle East
Princeton subject headings:
Geology, Stratigraphic--Paleozoic.
Geology--Africa, Southern.
Geology--Antarctica.
Geology--Middle East.