The Devonian Old Port Formation is a mapped bedrock unit in Pennsylvania, Maryland, and West Virginia.

The Devonian Foreknobs Formation is a mapped bedrock unit in Pennsylvania, Maryland, Virginia, and West Virginia.

The Devonian Catskill Formation (Dck) or the Catskill clastic wedge is a unit of mostly terrestrial sedimentary rock found in Pennsylvania and New York. Minor marine layers exist in this ...

The Devonian Hamilton Group (Dh) is a mapped bedrock unit in New York, Pennsylvania, Maryland, and West Virginia. In Virginia, it is known as the laterally equivalent Millboro Shale."Map ...

The Huntley Mountain Formation (abbreviated MDhm) is a late Devonian and early Mississippian mapped bedrock unit in Pennsylvania, in the United States. The formation is composed of relatively soft grayish-red ...

A rift lake is a lake formed as a result of subsidence related to movement on faults within a rift zone, an area of extensional tectonics in the continental crust ...

The New Red Sandstone is a chiefly British geological term for the beds of red sandstone and associated rocks laid down throughout the Permian (280 million years ago) to the ...

Scientists use geological periods as the time scale that defines the history of the Earth. The surface of the Earth is made up of layers of rock, with the most ...