Geologists have divided Earth's history into an international standard, which was set up from 1820-1870, and it is constantly being refined and improved. These geological time divisions are based on studies of the sequence of fossils through time, and on exact radiometric dating in millions of years.

Dinosaurs are found the period of Earth's history known as the Mesozoic Era, which began 250 million years ago and ended 65 million years ago. The Mesozoic is further subdivided into three periods, the Triassic, Jurassic, and Cretaceous.

Fossils show that the dinosaurs originated during the Mid to Late Triassic, perhaps 230-235 million years ago, and they remained the dominant land animals for another 160 million years, until they died out at the end of the Cretaceous.

For further information on this and the evolutionary aspects follow this link:-

To Huw Boulton's Home Page


Byron's Dinosaurs Home Page