acritarch alamo bolide impact algae ammonite antler orogeny appalachian mountains archaeopteris australia baltica bothriolepis brachiopod bryozoa caledonian orogeny cambrian carbon dioxide carbonate carboniferous cladoselache cladoxylopsid climactichnites climate conodont continent coral coral reef cretaceous devon digby mclaren digital object identifier dunkleosteus england epoch equator erosion euramerica europe evolution extinction event falls of the ohio state park fern fish forest fossil genus geologic time scale gondwana great britain greenhouse gas hadley cell hederellid hematite idaho international commission on stratigraphy jurassic landform late devonian extinction laurasia laurentia lignin list of fossil sites lungfish mississippian mite moss nevada north america ocean ohio old red sandstone ordovician ostracoderm paleozoic pangaea panthalassa permian phacops rana planet plant plate tectonics prototaxites reef rheic ocean rugosa sarcopterygii scandinavia scorpion shark silurian soil south america spermatophyte stratum stromatoporoidea supercontinent tetrapod tiktaalik triassic trilobite tropic of capricorn ural ocean vertebrate wattieza western europe wikimedia commons wood