Tuscarora Formation

Tuscarora Formation Stratigraphic range: Early Silurian
Outcrop of Tuscarora Formation in Thickhead Wild Area, Centre County, Pennsylvania
Type	sedimentary
Sub-units	Castanea Member
Underlies	Clinton Group and Rose Hill Formation
Overlies	Juniata Formation
Lithology
Primary	quartzarenite (sandstone)
Other	conglomerate
Location
Region	Appalachian Mountains
Extent	Pennsylvania, Maryland, West Virginia, Virginia
Type section
Named for	Tuscarora Mountain
Named by	Darton and Taff

The Silurian Tuscarora Formation — also known as Tuscarora Sandstone or Tuscarora Quartzite — is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia, USA.

The Tuscarora is a thin- to thick-bedded fine-grained to coarse-grained orthoquartzite. It is a white to medium-gray or gray-green subgraywacke, sandstone, siltstone and shale, cross-stratified and conglomeratic conglomerate in parts, containing a few shale interbeds. There is one named member of this formation: Castanea, occurring at the top, leaving the Lower and Middle Tuscarora Formation at the bottom. This formation has been called the "White Medina Sandstone" in West Virginia.

The Tuscarora is a lateral equivalent of the Minsi and Weiders members of the Shawangunk Formation in eastern Pennsylvania, New Jersey, and New York, and of the Massanutten Formation, a sandstone in Virginia. The Tuscarora and its lateral equivalents are the primary ridge-formers of the Ridge-and-Valley Appalachians in the eastern United States It is typically 935 feet thick in Pennsylvania, and in Maryland varies from 60 feet to 400 feet thick from east to west.

The depositional environment of the Tuscarora has always been interpreted as mostly terrestrial or shallow marine deposits resulting in a molasse sequence produced by the Taconic orogeny. It is thought to represent a vast sand shoal along the margin of the Iapetus Ocean.