Home > Diorama > Timeline > Diorama Timeline > Cretaceous Related Pages Diorama Storyline Read a detailed description of how the Diorama's 300 million years of history unfold. Dinosaur Timeline Learn more about the Cretaceous Period and the dinosaurs who lived at that time. Dinosaur Explorer See additional photos and learn more about the Trachodon, Ornithomimus, Elasmosaurus, and Pteranodon