Mesozoic that would move into their current positions during the next era. The climate of the Mesozoic was varied, alternating between warming and cooling periods. Overall, however, the Earth was hotter than it is today. Dinosaurs appeared in the Late Triassic and became the dominant terrestrial vertebrates early in the Jurassic, occupying this position for about 135 million years until their demise at the end of the Cretaceous. Birds first appeared in the Jurassic, having evolved from a branch of theropod dinosaurs. The first mammals also appeared during the Mesozoic, but would remain small—less than 15 kg (33 lb)—until the Cenozoic.
Orcombe Point cliffs further east. The coastal exposures along the coastline provide a continuous sequence of Triassic, Jurassic and Cretaceous rock formations spanning approximately 185 million years of the Earth's history. The localities along the Jurassic Coast includes a large range of important fossil zones. Orcombe Point is the western end of the Jurassic Coast and the South West Coast Path includes the entire length of the site. The ascent to Orcombe Point shows the successive layers of different sedimentary rocks, which were deposited under varying geological conditions. At the base are cross-bedded sandstones. Towards the top, the rock types are those