Jerarquías

First period of the Cenozoic, comprising the major portion of the era. It extends from 65.8 million to 2.6 million years ago. The Tertiary is subdivided into five epochs: Paleocene, Eocene, Oligocene, Miocene, and Pliocene. Some authorities, chiefly European, have lately replaced the Tertiary with two new time divisions: Paleogene (comprising the earlier three epochs of the period) and Neogene (covering the final two).