Geologic Time Scale

Geologic Time Scale Era System & Period Series & Epoch Some Distinctive Features Years Before Present Quaternary Recent & Holocene Modern man. 11,000 Pleistocene Early man; northern glaciation. 1/2 to 2 million Pliocene Large camivores. 13±1 million Miocene First abundant grazing mammals. 25+1 million Tertiary Oligocene Large running mammals. 36±2 million Eocene Many modern types of mammals. 58±2 million Paleocene First placental mammals. 63±2 million Cretaceous late First flowering plants; climax of early dinosaurs and ammonites, followed by Cretaceous-Tertiary extinction. 135±5 million Jurassic late First birds, first mammals Medial early, dinosaurs and ammonites abundant. 181±5 million Triassic First dinosaurs. Abundant cycads and conifers. 230±10 million Permian Extinction of most kinds of marine animals, including trilobites. Southern glaciation. 280±10 million Carboniferous Pennsylvanian Great coal forests, conifers. Sharks and amphibians abundant. 310±10 million Mississippian Large reefs, numerous scale trees and seed ferns. 345±10 million Devonian First amphibians; ammonites; fishes abundant. 405±10 million Silurian First terrestrial plants and animals. 425±10 million Ordovician First fishes; Invertebrates dominant. 500±10 million Cambrian First abundant record of marine life, trilobites dominant 600±50 million Precambrian Proterozoic Fossils extremely rare, consisting of primitive aquatic plants. Evidence of glaciation. Oldest dated algae, over 2,600 million years; oldest dated meteorites 4500