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	Carbonization A plant fossil may consist of a thin film of the carbon that the plant originally contained. Masses of these fossils crammed together make coal.   Previous: Back Book: Prehistoric Life Section: Prehistoric Chapter: Secrets in Stone