Columbia subject headings:
Geology, Stratigraphic--Paleozoic.
Geology, Stratigraphic--Precambrian.
Geology--Spain--Badajoz (Province)
Harvard subject headings:
Princeton subject headings:
Geology, Stratigraphic--Paleozoic.
Geology, Stratigraphic--Precambrian.
Geology--Spain--Badajoz (Province).