| Potomac Group | |
| Type: | Group |
| Age: | Cretaceous, |
| Period: | Early Cretaceous |
| Region: | ,,, |
| Subunits: | Patuxent Formation, Arundel Formation, Patapsco Formation, Raritan Formation, Potomac Formation (?) |
| Underlies: | Raritan Formation, Magothy Formation |
| Overlies: | Boonton Formation |
The Potomac Group is a geologic group in Delaware, Maryland, New Jersey, and Virginia. It preserves fossils dating back to the Cretaceous period. An indeterminate tyrannosauroid and Priconodon crassus, a nodosaurid, are known from indeterminate sediments belonging to the Potomac Group.[1] The Potomac Group was initially believed to have been Late Jurassic in age by Othniel Charles Marsh[2] but later studies, such as Clark (1897), have found that the Potomac Group is in fact Early-Late Cretaceous (Aptian-Turonian) in age.[3]