| St. Maughan's Formation | |
|---|---|
| Stratigraphic range: Devonian | |
 Mynydd Troed, the base of the hill consisting of St. Maughan's Formation | |
| Type | Formation |
| Unit of | Old Red Sandstone |
| Lithology | |
| Primary | Mudstone |
| Other | Sandstone, Conglomerate |
| Location | |
| Region | Wales |
| Country |  United Kingdom |
The St. Maughan's Formation is a geologic formation in Wales. It preserves fossils dating back to the Devonian period.