| Dunleith Formation | |
|---|---|
| Stratigraphic range: Ordovician | |
| Type | Formation |
| Unit of | Galena Group |
| Location | |
| Region |  Illinois  Iowa  Missouri  Wisconsin |
| Country |  United States |
The Dunleith Formation is a geologic formation in Illinois. It preserves fossils dating back to the Ordovician period.