Phanerozoic of Pangaea into Laurasia and Gondwana in an extinction known as the Jurassic-Cretaceous extinction. Sea levels rose, destroying fern prairies and creating shallows. Ichthyosaurs became extinct whereas sauropods, as a whole, did not; in fact, some species, like "Titanosaurus", lived until the K-T extinction. The increase in sea-levels opened up the Atlantic sea way which would continue to get larger over time. The divided world would give opportunity for the diversification of new dinosaurs. The Cretaceous is the longest period in the Mesozoic, spans from 145 million to 66 million years ago, and is divided into two epochs: Early Cretaceous,
The Magic School Bus In the Time of the Dinosaurs periods (Triassic, Jurassic, and Cretaceous) were seen in the book; only the book focuses with all of the time periods. This is because it was due to time constraints; time constraints in order for the episode to be up to 30 minutes (30 minutes like all episodes in the TV series). In this episode, the kids visit Ms. Frizzle's old friend, Dr. Carmina Skeledon at a dinosaur dig, as opposed to Jeff in the book. Dr. Skeledon lets Arnold see a fossilized dinosaur egg that Ms. Frizzle finds as the kids are leaving, and he still has it when they