Paleogene

Paleogene
Temporal information Time span 43 million years from the end of the Cretaceous Period 66 million years ago to the beginning of the Neogene Period 23.03. Part of Cenozoic Era Chronological information
Previous period Cretaceous	Following period Neogene

The Paleogene is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 million years ago to the beginning of the Neogene Period 23.03 Mya. It is the first period of the Cenozoic Era and the tenth period of the present Phanerozoic Eon. The Paleogene is most notable for being the time during which mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous–Paleogene extinction event that ended the preceding Cretaceous Period.