| Patapsco Formation | |
|---|---|
| Stratigraphic range: | |
| Outcrop of the Patapsco Formation at Reynold's Mine, Anne Arundel County, Maryland showing the Arundel Formation overlain by the Patapsco Formation | |
| Type | Formation |
| Unit of | Potomac Group |
| Underlies | Raritan Formation |
| Overlies | Arundel Formation |
| Thickness | 200 feet (60 m) |
| Lithology | |
| Primary | clay, sand |
| Other | silt |
| Location | |
| Region | Virginia, Maryland |
| Country | United States |
| Type section | |
| Named for | Patapsco River |
| Named by | William Bullock Clark (1897) [1] |
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. [1] [2] It preserves fossils such as plants and molluscs dating back to the Cretaceous period. [1]