Phanerozoic the Mesozoic features the rise of reptiles on their 150 million year conquest of the Earth on the land, in the seas, and in the air. There are three periods in the Mesozoic: Triassic, Jurassic, and Cretaceous. The Triassic ranges from 250 million to 200 million years ago. The Triassic is a transitional time in Earth's history between the Permian Extinction and the lush Jurassic Period. It has three major epochs: Early Triassic, Middle Triassic and Late Triassic. The Early Triassic lasted between 250 million to 247 million years ago, and was dominated by deserts as Pangaea had not yet
The Gap (Sydney) tablet. The Gap is formed from Sydney sandstone making it part of Sydney basin. The cliff was laid as sediment more than 200 million years ago in the Triassic period. During the Jurassic era, 40 million years later, a cataclysmic event resulted in an enormous crack forming within the strata. This fault allowed erosion from wave action to create the cliff line around Sydney. Tessellated basalt rock platforms lie at the base of the cliff because The Gap is bordered to the south and west by an older sequence of largely low-grade metamorphic and granitic rocks of the Lachlan Fold