Columbia subject headings:
Geology, Stratigraphic--Devonian.
Geology--England--Devon.
Geology--History.
Science--History.
Harvard subject headings:
Geology, Stratigraphic--Devonian
Geology--England--Devon.
Geology--History
Science--History
Princeton subject headings:
Geology, Stratigraphic--Devonian.
Geology--England--Devon.
Geology--History.
Science--History.