| Scales Shale Stratigraphic range: Ordovician |
|
|---|---|
| Type | Formation |
| Underlies | Fort Atkinson Limestone |
| Overlies | Trenton Limestone |
| Location | |
| Region | Illinois, Indiana |
| Country | United States |
The Scales Shale is a geologic formation in Illinois. It preserves fossils dating back to the Ordovician period.