Jurassic

The Jurassic is a geologic period and system that extends from 201.3± 0.6 Ma (million years ago) to 145± 4 Ma; that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic Era, also known as the Age of Reptiles. The start of the period is marked by the major Triassic–Jurassic extinction event. Another extinction event, the Late Piensbachian/Early Toarcian event, occurred in the Early Jurassic, and a third extinction event, the Late Tithonian event, occurred at the end of the Jurassic; however neither of these two events rank among the 'Big Five' mass extinction. The Jurassic is named after the Jura Mountains within the European Alps, where limestone strata from the period was first identified.

• http://en.wikipedia.org/wiki/Jurassic