A Journey Through Time Since the Precambrian: Quick Facts

Written and fact-checked by

The Information Architects of Encyclopaedia Britannica

Photos

Dinosaur phylogeny, or family tree with individual dinosaurs visible.

Cambrian paleogeography

A chart showing the Ordovician period within the Paleozoic era on the geologic time scale, listing its division into Lower, Middle, and Upper epochs, with corresponding stage names and their ages in millions of years ago.

Illustration of an early Silurian coral-stromatoporoid community showing various labeled marine organisms, including corals, bryozoans, brachiopods, crinoids, trilobites, and a nautiloid, arranged on and around a block of seafloor substrate with a scale bar indicating centimeters.

Early Devonian map

A chart detailing the Carboniferous period within the Paleozoic era, showing its division into Mississippian and Pennsylvanian subperiods, with corresponding epochs, ages, and their ranges in millions of years ago.

Early Permian Epoch

Line graph showing the number of marine animal families from the Precambrian era to the present, with illustrations of key groups such as trilobites, ammonoids, marine reptiles, and diatoms. The graph highlights major extinction events and a rise to 1,900 living families today.

Pangea: Late Jurassic Period

dinosaur phylogeny

See All Images →

Topics

geologic time dating How Old Is Earth?Precambrian geochronology fossil record Phanerozoic Eon Lipalian interval era index fossil epoch