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. Paleozoic

Anotations

Scope note:

The second period of the Paleozoic, following the Cambrian and preceding the Silurian. It extends from about 448 to 443 million years ago. It is marked by a significant radiation of marine life and the first colonization of land, by nonvascular plants.