Hierarchy classification:

1. top of the aat hierarchies
2. Styles and Periods Facet
3. Styles and Periods (hierarchy name)
4. [styles, periods, and cultures by general era]
5. geologic time scale
6. Phanerozoic
7. Cenozoic
8. Paleogene

Additional parents:

1. top of the aat hierarchies
2. Styles and Periods Facet
3. Styles and Periods
4. styles, periods, and cultures by general era
5. geologic time scale
6. Phanerozoic
7. Cenozoic
8. Tertiary

Anotations

Scope note:

On the geologic time scale the third epoch of the Tertiary period, following Eocene and preceding Miocene, or the first period of more recently designated Paleogene. It extends from about 34 million to 22 million years ago. The epoch is marked by the further development of mammals. The name Oligocene refers to the relatively few moder animals originating during the epoch.