Denver Formation

The Denver Formation is a geological formation that is present within the central part of the Denver Basin that underlies the Denver, Colorado, area. It ranges in age from latest Cretaceous (Maastrichtian) to early Paleocene (Danian), and includes sediments that were deposited before, during and after the Cretaceous-Paleogene boundary event.

The formation is known for its paleontological resources, including dinosaur remains that are found in the Late Cretaceous part of the formation, and it includes aquifers that are important sources of water for the area. Some of North America's most iconic end-Cretaceous dinosaurs, such as Triceratops and Tyrannosaurus, were first identified from the Denver Formation before being properly described from better-preserved remains in end-Cretaceous formations further north. The formation also preserves one of the most world's most diverse earliest Paleocene mammalian faunas, providing an important record of the diversification of mammals in the immediate aftermath of the K-Pg extinction.