Columbia subject headings:
Geology, Stratigraphic--Cambrian--Congresses.
Geology, Stratigraphic--Precambrian--Congresses.
Paleontology--Cambrian--Congresses.
Paleontology--Precambrian--Congresses.
Trace fossils--Congresses.
Harvard subject headings:
Princeton subject headings:
Matthew, George Frederic, 1837-1923.
Paleontology--Cambrian--Congresses.
Paleontology--Pre-Cambrian--Congresses.