unit is a subdivision of geologic time. It is a numeric representation of an intangible property (time). Eon, era, period, epoch, subepoch, age, and subage...

The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which...

and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference...

Ordovician epoch (470.0 Ma – 458.4 Ma) Darriwilian stage/age (467.3 Ma – 458.4 Ma) Dapingian stage/age (470.0 Ma – 467.3 Ma) Lower Ordovician epoch (485.4...

The geology of Mars is the scientific study of the surface, crust, and interior of the planet Mars. It emphasizes the composition, structure, history...

In the geologic timescale, the Přídolí Epoch (Czech pronunciation: [ˈpr̝̊iːdoliː]) is the uppermost subdivision of the Silurian Period, dated at between...

The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between 237 Ma and 201.4 Ma (million...

Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58 million years ago. It is the second and most recent epoch of the Neogene...

ˈiːoʊ-/ EE-ə-seen, EE-oh-) is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in...

is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous...