The Triassic is a geologic period and a stratigraphic system that spans 50.5 million years from the end of the Permian Period 251.902 Ma to the beginning of the Jurassic Period 201.4 Ma. The Triassic Period is the first and shortest geologic period of the Mesozoic Era, and the seventh period of the Phanerozoic Eon. The start and the end of the Triassic Period featured major extinction events.