Devonian Mahantango Formation is a mapped bedrock unit in Pennsylvania, West Virginia, and Maryland. It is named for the North branch of the Mahantango Creek...

Pennsylvania Mahantango Creek (Snyder County), a tributary of the Susquehanna River in Snyder and Juniata counties, in Pennsylvania Mahantango Formation, a mapped...

shale with some sandstone. There are two main formations encompassed by the group: the Mahantango Formation and the Marcellus Shale. In southwestern Virginia...

shales near the middle of the Mahantango Formation are classified by geologists as slope-formers. Marcellus and Mahantango shale beds dipping at 60° to...

The Knox Supergroup, also known as the Knox Group and the Knox Formation, is a widespread geologic group in the Southeastern United States. The age is...

The Salina Group or Salina Formation is a Late Silurian-age, Stratigraphic unit of sedimentary rock that is found in Northeastern and Midwestern North...

The Monongahela Formation is a geologic formation in West Virginia, Pennsylvania, Ohio, and Maryland. It is dated to the Carboniferous period. The top...

the Portage Group. The West Falls formation is bounded above by the Java Formation and below by the Sonyea Formation. It comprises the Angola Shale and...

The Rhinestreet Shale is a geologic formation in the Appalachian Basin. It dates back to the Devonian period. The Rhinestreet is an organic or Black Shale...

The Tully Formation is a geologic unit in the Appalachian Basin. The Tully was deposited as a carbonate rich mud, in a shallow sea at the end of the Middle...