There are 18 matches
| Collection | Authorizer | Collection name | Reference |
|---|---|---|---|
| 23613 | S. Holland | Glenwood Formation Gastropoda and Monoplacophora, Illinois and Iowa Blackriveran - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23614 | S. Holland | Pecatonica Formation Gastropoda and Monoplacophora, Illinois and Iowa Blackriveran - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23615 | S. Holland | Mifflin Formation Gastropoda and Monoplacophora, Illinois and Iowa Blackriveran - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23617 | S. Holland | Grand Detour Formation Gastropoda and Monoplacophora, Illinois and Iowa Blackriveran - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23619 | S. Holland | Nachusa Formation Gastropoda and Monoplacophora, Illinois and Iowa Blackriveran - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23620 | S. Holland | Quimbys Mill Formation Gastropoda and Monoplacophora, Illinois and Iowa Blackriveran - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23621 | S. Holland | Spechts Ferry Formation Gastropoda and Monoplacophora, Illinois and Iowa Blackriveran/Rocklandian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23622 | S. Holland | Guttenberg Formation Gastropoda and Monoplacophora, Illinois and Iowa Rocklandian/Kirkfieldian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23623 | S. Holland | Ion Formation, Buckhorn Member Gastropoda and Monoplacophora, Illinois and Iowa Kirkfieldian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23644 | S. Holland | Ion Formation, St. James Member Gastropoda and Monoplacophora, IL and IA Kirkfieldian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23651 | S. Holland | Dunleith Fm, Beecher Member Member Gastropoda and Monoplacophophora, IL and IA Shermanian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23653 | S. Holland | Dunleith Fm, Eagle Point Member Gastropoda and Monoplacophora, Illinois and Iowa Shermanian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23656 | S. Holland | Dunleith Fm, Fairplay Member Gastropoda and Monoplacophora, Illinois and Iowa Shermanian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23659 | S. Holland | Dunleith Fm, Mortimer Member Gastropoda and Monoplacophora, Illinois and Iowa Shermanian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23664 | S. Holland | Dunleith Fm, Rivoli Member Gastropoda and Monoplacophora, Illinois and Iowa Shermanian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23667 | S. Holland | Dunleith Fm, Sherwood Member Gastropoda and Monoplacophora, Illinois and Iowa Shermanian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23668 | S. Holland | Dunleith Fm, Wall Member Gastropoda and Monoplacophora, Illinois and Iowa Shermanian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |
| 23670 | S. Holland | Dunleith Fm, Wyota Member Gastropoda and Monoplacophora, Illinois and Iowa Shermanian - Ordovician 4-5 - Illinois, Iowa | Sloan and Webers (1987) |