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. It appears to be roughly concurrent with the Tuscaloosa Formation of Alabama.

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. An important locality is the former Bladen County landfill annex in Elizabethtown, North Carolina, which contains the richest known fauna from the formation. 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.

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.