The Geologic Column

By Sopia Avila
  • 255,000 BCE

    Proterozoic

    Simple multicellular sea creatures develop; algae and plankton develop; eukaryotic
  • 251,000 BCE

    Mesozoic: Triassic

    First dinosaurs; rise of mammal-like reptiles
  • 199,600 BCE

    Mesozoic: Jurassic

    Giant dinosaurs; early birds; first mammals
  • 180,000 BCE

    Pleistocene Epoch

    Ice Age(s); mass extinctions; rise of man
  • 145,000 BCE

    Mesozoic: Cretaceous

    Mass extinctions (including dinosaurs); flowering plants appear
  • 65,000 BCE

    Tertiary: Paleocene Epoch

    Early mammals become dominant; rise of modern birds
  • 55,800 BCE

    Tertiary: Eocene Epoch

    First horses
  • 54,200 BCE

    Paleozoic: Cambrian

    Sudden explosion of life; trilobites dominant; rise of other marine invertebrates; some vertebrates
  • 53,000 BCE

    Tertiary: Pliocene Epoch

    Peak of mammals; modern invertebrates
  • 48,830 BCE

    Paleozoic: Ordovician

    Trilobites abundant; vertebrates increase
  • 44,370 BCE

    Paleozoic: Silurian

    Land colonized by arthropods and plants
  • 41,600 BCE

    Paleozoic: Devonian

    First amphibians; freshwater fish; wingless insects
  • 40,000 BCE

    Hadean

    Formation of earth (uninhabitable)
  • 40,000 BCE

    Archean

    Earth becomes habitable; spontaneous generation of first cells; rise of bacteria and cyanobacteria
  • 35,920 BCE

    Paleozoic: Mississipian*

    Amphibians spread; sharks and bony fish; winged insects
  • 33,900 BCE

    Tertiary: Oligocene Epoch

    Primitive apes; whales; first modern mammals
  • 31,830 BCE

    Paleozoic: Pennsylvanian*

    Giant insects; first reptiles
  • 29,900 BCE

    Paleozoic: Permian

    Modern insects; reptiles spread; evergreens; extinction of trilobites
  • 23,000 BCE

    Tertiary: Miocene Epoch

    Rise of gazing mammals
  • 11,477 BCE

    Quatenary: Recent (Holocene) Epoch

    End of the last Ice Ace; rise of human civilization