The Triassic Period
The Triassic period lasted 50.5 Million years, it was the very first and shortest period of the Mesozoic Era. It was divided into three periods; the Early Triassic, the Middle Triassic, and the Late Triassic. Dinosaurs first appeared in the Late Triassic period. The primary/dominant spieces of the Triassic period were the early ancestors of modern crocodilians called "pseudosuchians." Pangaea was the landmass that dominated during this time.
The Jurassic Period
The Jurassic Period lasted around 43 Million years and i the first period of the Cenozoic Era. Its divided into three periods, the Paleocene, the Eocene and the Oligocene. This period saw the dinosaurs flourish more than when they first appeared during the Triassic Period.
The Cretaceous Period
The Cretaceous Period lasted 79 Million years and was the last period of the Mesozoic Era. During this period Dinosaurs reached their height and were the dominant animals on the planet during this time.