Triassic Triassic The Triassic () is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.9 million years ago (Mya), to the beginning of the Jurassic Period Mya. The Triassic is the first period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it would take well into the middle of this period for life to recover its former diversity. Therapsids and archosaurs were the chief terrestrial
Jurassic Coast period of 185 million years, and disclosing an almost continuous sequence of rock formations covering the Triassic, Jurassic and Cretaceous periods. The fossils found in the area and the coastal geomorphologic features of this dynamic coast, have advanced the study of earth sciences for more than two hundred years. The area covered by the designation comprises the land between the mean low water mark and the top of the cliffs or the back of the beach. The fossils found in abundance along this coastline provide evidence of how animals and plants evolved in this region. During the Triassic this area