Bladen Formation

The Bladen Formation is a geologic formation from the Late Cretaceous (middle Campanian) of North Carolina and South Carolina, USA. It is known for a plethora of terrestrial and aquatic vertebrate fossils, including dinosaurs and mosasaurs.^[1] It appears to be roughly concurrent with the Tuscaloosa Formation of Alabama.^[2]

Unlike many other Cretaceous geologic formations from eastern North America, which were deposited in entirely marine environments, the Bladen Formation appears to have been deposited in a former river delta in an estuarine habitat, allowing for a mixture of freshwater, terrestrial, and marine fauna.^[3] An important locality is the former Bladen County landfill annex in Elizabethtown, North Carolina, which contains the richest known fauna from the formation.^[4][5] Another notable locality is near Quinby in Florence County, South Carolina, which also appears to have been deposited in a nonmarine environment with minor marine influence.^[6]

It is deposited as a thin layer over the Tar Heel/Coachman Formation, which is often confused with. In North Carolina, it underlies the Maastrichtian-aged Peedee Formation, while in South Carolina it underlies the slightly younger Campanian-aged Donoho Creek Formation.^[7]