Columbia subject headings:
Harvard subject headings:
Geology, Stratigraphic--Eocene
Geology, Stratigraphic--Oligocene
Geology--Trans-Pecos (Tex. and N.M.)
Princeton subject headings:
Geology, Stratigraphic--Eocene.
Geology, Stratigraphic--Oligocene.
Geology, Structural.
Geology--Trans-Pecos (Tex. and N.M.).