| Marnes Rouges Inférieures Formation | |
| Type: | Geological formation |
| Age: | Maastrichtian ~ |
| Period: | Maastrichtian |
| Prilithology: | Mudstone |
| Otherlithology: | Sandstone |
| Namedfor: | French: "Lower Red Marls" |
| Region: | Occitania |
| Coordinates: | 42.9°N 2.3°W |
| Paleocoordinates: | 34.8°N 2°W |
| Underlies: | Calcaires de Vignevieille |
| Overlies: | Grès d'Alet |
| Thickness: | Over 150m (490feet) |
The Marnes Rouges Inférieures Formation is a Late Cretaceous geologic formation found in the French Pyrenees. It predominantly consists of red mustone, with minor brown mudstone and sandstone.[1] Dinosaurs, dinosaur eggs and avialian stem-birds have been reported from the formation.[2]