Magothy Formation

Geologic Time Period
Upper Cretaceous

Coastal Plain - Primarily Subsurface Unit

The following description was published in GM13 Geologic Map of New Castle County, Delaware, Ramsey, K.W., 2005:

Dark-gray to gray silty clay to clayey silt that contains abundant fragments of lignite; grades downward into a very fine to fine sand with scattered and discontinuous thin beds of clayey silt with lignite fragments. Thickness ranges from 20 to 50 ft. Updip in the vicinity of the Chesapeake and Delaware Canal, the Magothy fills channels incised into the Potomac Formation and is discontinuous in its extent. Interpreted to have been deposited in coastal to nearshore environments.