Peedee Formation

The Peedee Formation is a geologic formation in North and South Carolina. A marine deposit representing an inner neritic environment,^[2] named for exposures along the Great Peedee River, it preserves invertebrate (primarily belemnites, echinoderms and foraminifera) and vertebrate (primarily shark teeth, with some marine reptile remains) fossils dating to the Late Cretaceous (Maastrichtian).^[1]

TypeFormation

Sub-unitsRocky Point Member, Island Creek Member

UnderliesCastle Hayne Limestone

OverliesBlack Creek Group

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Peedee Formation
Stratigraphic range: Early to Late Maastrichtian, 71.0–66.9 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Cucullaea, a fossil bivalve from the Peedee Formation (South Carolina)
Type	Formation
Sub-units	Rocky Point Member, Island Creek Member
Underlies	Castle Hayne Limestone
Overlies	Black Creek Group
Thickness	Up to 886 ft (270 m)
Lithology
Primary	Glauconitic to argillic sandstone
Other	Claystone, limestone
Location
Region	North Carolina, South Carolina
Country	United States
Type section
Named for	Pee Dee River, type locality: Burches Ferry, South Carolina[1]

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The formation is notable for its occurrence of Belemnitella americana, known as the Pee Dee Belemnite (PDB), a long-standing standard in stable carbon isotope research. A single pterosaur femur, possibly an Azhdarchid, from the Peedee formation is one of the few pterosaur body fossils found in Eastern North America.^[3]

The stratigraphy of the formation spans from the early Maastrichtian (in South Carolina)^[4] to the late Maastrichtian shortly before the Cretaceous-Paleogene extinction event. The formation is divided into several members, including the early-mid Maastrichtian Rocky Point Member and the late Maastrichtian Island Creek Member.^[2] Based on its fauna, it appears to be roughly concurrent with the Navesink Formation from New Jersey.^[3]