| Manitoulin Dolomite | |
| Type: | Formation |
| Age: | Llandovery |
| Period: | Llandovery |
| Region: | Ohio, Ontario, and Michigan |
| Country: | Canada and United States |
| Unitof: | Cataract Group |
| Underlies: | Cabot Head Shale |
| Overlies: | Big Hill Formation |
The Manitoulin Dolomite is a geologic formation in Ontario. It preserves fossils dating back to the Silurian period.