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	Platyceras Gastropods - the snails - are among the oldest fossils. Platyceras had a hooked tip to the shell.   Previous: Back Book: Prehistoric Life Section: Prehistoric Chapter: The Silurian Reef