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	Trace Fossil Fossil footprints or worm tracks, showing where an animal has been, are called trace fossils.   Previous: Back Book: Prehistoric Life Section: Prehistoric Chapter: Secrets in Stone