Dinosaurs and Prehistoric Animals:The Western Interior Seaway 80 Million Years Ago

the Midwest of North America under water

Tylosaur - a huge 50 foot long sea serpent (mosasaur) and it's smaller cousins Halisaurus and Clidastes

Elasmosaurus - a huge long-necked plesiosaur

Archelon - a giant sea turtle similar to modern leatherbacks

Hesperornis and Baptornis - flightless aquatic birds

Quetzalcoatlus and the smaller but still very big pterosaurs

Pteranodon and Nyctosaurus

Ichthyornis a toothed gull-like bird