Prehistoric Life Prehistoric Secrets in Stone The Earliest Fossils The Silurian Reef Trilobites Fish The Coal Forests Early Reptiles and Amphibians Sea Reptiles Flying Reptiles The Teeming Seas Hunting Dinosaurs Biggest Dinosaurs Two-Footed Plant Eaters Plated and Armoured Dinosaurs Horned Dinosaurs The Mammal Age Dawns Grassland Mammals The Ice Age	Late Forms of Plant Eater Some long-necked plant eaters survived until the end of the Cretaceous period, especially in South America, where strange forms developed. Saltasaurus was unusual in having armour on its back. Amargasaurus had a sail-like crest on its neck.   Previous: Back Book: Prehistoric Life Section: Prehistoric Chapter: Biggest Dinosaurs