| Patapsco Formation | |
| Type: | Formation |
| Period: | Cenomanian |
| Prilithology: | clay, sand |
| Otherlithology: | silt |
| Namedfor: | Patapsco River |
| Namedby: | William Bullock Clark (1897)[1] |
| Unitof: | Potomac Group |
| Underlies: | Raritan Formation |
| Overlies: | Arundel Formation |
| Thickness: | 200feet |
The Patapsco Formation is a geologic formation of varigated clays, sandy clays, and sand in Virginia, the District of Columbia, Maryland, Delaware, Pennsylvania, and in the subsurface of New Jersey.[2] It preserves fossils such as plants and molluscs dating back to the Cretaceous period.