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	Wenlock Limestone Limestone is made up totally of fossil fragments. This rock is from an area in Britain where the seas were clear enough for large reefs to form.   Previous: Back Book: Prehistoric Life Section: Prehistoric Chapter: The Silurian Reef