Columbia subject headings:
Geology--Trans-Pecos (Tex. and N.M.)--Guidebooks.
Igneous rocks--Trans-Pecos (Tex. and N.M.)--Guidebooks.
Harvard subject headings:
Geology--Trans-Pecos (Tex. and N.M.)--Guidebooks.
Igneous rocks--Trans-Pecos (Tex. and N.M.)--Guidebooks.
Trans-Pecos (Tex. and N.M.)--Guidebooks.
Princeton subject headings: