Tully Formation

Tully Formation
Stratigraphic range: Devonian
Tully Formation at Taughannock Falls State Park
TypeFormation
Sub-units
New York
  • New Lisbon Member
  • Laurens Member
  • West Brook Member
Pennsylvania
  • Weissport Member
  • Brodhead Creek Member
  • Lehighton Member
UnderliesHarrell Shale/Genesee Group
OverliesHamilton Group
Lithology
PrimaryLimestone
OtherShale, Siltstone, and Sandstone
Location
RegionMaryland, New York, Pennsylvania, West Virginia
CountryUnited States, Canada
Type section
Named forTully, NY
Named byVanuxem (1839)

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 Devonian. Outcrops for the Tully are found in New York State and Pennsylvania. It is also found subsurface in western Maryland and northern West Virginia. A number of fossil remains from marine organisms may be found in Tully outcrops.