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. Mesozoic

Anotations

Scope note:

The first period of the Mesozoic, extending from about 250 to 208 million years ago. Following the mass extinctions of the Permian, many new forms of flora and fauna emerged in the Triassic including ocean reptiles and terrestrial vertebrates such as dinosaurs. The first mammals, small shrew-like creatures, appeared in the late Triassic.