Geologic Timescale

By Sladesar

  • Cambrian Period 570-500 MYA

    Cambrian Period 570-500 MYA
    Earliest record of marine life. Trilopites are dominate.

  • Ordovician Period-500-435 MYA

    Ordovician Period-500-435 MYA
    Echinoderms and invertebrates are dominate. Mollusks become abundant. Earliest fisth that are jawless and later are jawed and armored fish.

  • Silurian Period- 435-395 MYA

    Silurian Period- 435-395 MYA
    Earliest terrestrial plants and animals. Tiktaalik Eurypterides develope.

  • Devonian Period-395- 345 MYA

    Devonian Period-395- 345 MYA
    Armored fish go extinct, but abundance of several species of fish. Earliers amphibians and ammonites.

  • Carboniferous Period- 345- 280 MYA

    Carboniferous Period- 345- 280 MYA
    Abundant sharks and amphibians. Large swamps, forests forming. Earliest reptiles, scale trees and seed ferns.

  • Permian Period 280- 225 MYA

    Permian Period 280- 225 MYA
    Extintion of many types of marine animals including Trilobites.

  • Mesozoic Triassic Period- 225- 195 MYA

    Mesozoic Triassic Period- 225- 195 MYA
    Earliest dinosaurs, abundant cycads and conifers.

  • Mesozoic Jurassic Period 195-136 MYA

    Mesozoic Jurassic Period 195-136 MYA
    Earliest birds and mammals abundant dinosaurs and ammonites.

  • Mesozoic Cretaceous Period 133-65 MYA

    Mesozoic Cretaceous Period 133-65 MYA
    Earliest flowering plants, climax of dinosaurs followed by their extinction. Great decline of brachiopods. Abundance of bony fish. K-T extinction.

  • Cenozoic Tertiary Period 65-1.8 MYA

    Earliest placental mammals, modern mammals, large running mammals.

  • Cenozoic Quaternary Period 1.8 MYA -Present

    Cenozoic Quaternary Period 1.8 MYA -Present
    Large carnivores,neandrathals, humans, mastodons.