Columbia subject headings:
Harvard subject headings:
Invertebrates, Fossil.
Paleontology--Illinois--Grundy County.
Paleontology--Illinois--Will County.
Paleontology--Pennsylvanian
Princeton subject headings:
Invertebrates, Fossil.
Paleontology--Illinois--Grundy County.
Paleontology--Illinois--Will County.
Paleontology--Pennsylvanian.