| Iola Formation | |
|---|---|
| Stratigraphic range: Carboniferous | |
 Fossiliferous limestone (Raytown Member, Iola Formation; Elk County, Kansas) | |
| Type | Formation |
| Unit of | Kansas City Group |
| Sub-units | Raytown Member |
| Location | |
| Region | Illinois, Oklahoma, Kansas, Iowa |
| Country | United States |
The Iola Formation is a geologic formation in Illinois, Iowa, Kansas and Oklahoma. It preserves fossils dating back to the Carboniferous period.
