Era/Period/Epoch Age Major Biological & Geologic Events (Millions of years) CENOZOIC Quaternary Ice Age begins and evolution of modern mammals; man reaches N. A.; general uplift of continent. Holocene (Recent) .01 Pleistocene 3 Tertiary Evolution and Development of major mammal groups; Cascadian Orogeny in northwestern United States; in latest Cenozoic, Eocene lake system. Pliocene 5.5 Miocene 25.5 Oligocene 36 Eocene 54 Paleocene 65 MESOZOIC Cretaceous 130 Extinction of dinosaurs; flowering plants flourish; height of Cordilleran Orogeny. Jurassic 185 First birds, dinosaurs and mammals continue to evolve; beginning of Cordilleran Orogeny which formed the Rocky Mountains. Triassic 230 Conifers evolved; first dinosaurs; first mammals; Appalachian Orogeny; some orogeny in Cordillera. PALEOZOIC Permian 265 Archaic reptiles and mammal-like reptiles evolve. Appalachian Orogeny. Pennsylvanian 310 First reptiles, coal swamps formed; beginning of the Appalachian Orogeny. Mississippian 355 Expansion of amphibians; much carbonate deposition; Antler Orogeny in Cordilleran Mobile Belt (Rocky Mountain area). Devonian 413 First land plants; first jawed fishes, sharks and bony fish; amphibians appear; Acadian Orogeny in the Appalachian belt. Silurian 425 Jawless fishes evolved; much reef development; evaporite mineral development. Ordovician 475 First vertebrate remains known from this time; Taconic Orogeny in Appalachian belt. Cambrian 600 First shelled invertebrates; major flooding of North America.