Columbia subject headings:
Geology, Stratigraphic--Devonian--Terminology.
Geology--North America--Terminology.
Harvard subject headings:
Princeton subject headings:
Geology, Stratigraphic--Devonian--Dictionaries.
Geology--North America, Eastern--Dictionaries.
Paleontology--North America, Eastern--Dictionaries.
Volcanism--North America, Eastern--Dictionaries.