Columbia subject headings:
Geology, Stratigraphic--Devonian--Congresses.
Geology, Stratigraphic--Silurian--Congresses.
Orogeny--Canada--Congresses.
Orogeny--Europe--Congresses.
Orogeny--United States--Congresses.
Harvard subject headings:
Geology, Stratigraphic--Devonian--Congresses.
Geology, Stratigraphic--Silurian--Congresses.
Orogeny--Canada--Congresses.
Orogeny--Europe--Congresses.
Orogeny--United States--Congresses.
Princeton subject headings:
Geology, Stratigraphic--Devonian--Congresses.
Geology, Stratigraphic--Silurian--Congresses.
Orogeny--Canada--Congresses.
Orogeny--Europe--Congresses.
Orogeny--United States--Congresses.