Geologic Timescale

  • Cambrian Period. 570-500 MYA.

    Cambrian Period. 570-500 MYA.
    Earliest marine life recorded Abundant amount of Triallbites.
  • Ordovician. 500-435 MYA.

    Ordovician. 500-435 MYA.
    Red and green algae. Mostly underwater.
  • Silurian. 435-335 MYA.

    Silurian. 435-335 MYA.
    Climate change that brought to the earth, called the greenhouse effect.
  • Devonian. 395-345 MYA.

    Devonian. 395-345 MYA.
    Plant growth. Ferns, horsetails, and seedplants appeared.
  • Carboniferous. 345-280 MYA.

    Carboniferous. 345-280 MYA.
    During the Carboniferous Period, it was part of a vast equatorial coastal swamp extending many hundreds of miles and barely rising above sea level.
  • Permian. 280-225 MYA.

    Permian. 280-225 MYA.
    During the Permian, the continents joined to form a single supercontinent, Pangea. Hot, dry conditions prevailed almost everywhere, and deserts were widespread. Marine invertebrates evolved into several lineages.
  • Triassic. 225-195 MYA.

    Triassic. 225-195 MYA.
    Many new vertebrates emerged during the Triassic. The seas became inhabited by large marine reptiles.
  • Jurassic. 195-136 MYA.

    Jurassic. 195-136 MYA.
    Dinosaurs. Mammals started to fly. Big ones were herbivores. Smaller were carnivores.
  • Cretaceous. 136-65 MYA.

    Cretaceous. 136-65 MYA.
    In the seas, marine invertebrates flourished, and bony fishes evolved. On land, flowering plants arose, and insects, bees in particular, began their thriving partnership with them.
  • Tertiary. 65-1.8 MYA.

    Tertiary. 65-1.8 MYA.
    The Tertiary has five subdivisions: Paleocene, Eocene, Oligocene, Miocene, and Pliocene epochs. During most of the Tertiary the spatial distribution of the major continents was largely similar to that of today.
  • Quaternary. 1.8-Present.

    Quaternary. 1.8-Present.
    The Quaternary follows the Tertiary Period.The Quaternary is subdivided into the Pleistocene Epoch and the Holocene Epoch and is characterized by major cyclical changes of climate on a global scale. These led to repeated invasions of vast areas by ice sheets.