Evidence About Earth’s Past (Book)

- Divisions of the Geologic Time Scale

The largest blocks of time on the geologic time scale are called “eons.” Eons are split into “eras.” Each era is divided into “periods.” Periods may be further divided into “epochs.” Geologists may just use “early” or “late.” An example is “late Jurassic,” or “early Cretaceous.” Figure shows you what the geologic time scale looks like.

The Geologic Time Scale.