Geologic Timescale


    Beginning of time here on earth. Contains the periods of Permian, Carboniferous, Ordovician, Devonian, Silurian, and Cambrian.
  • Cambrian Period (570 M-500 M)

    Cambrian Period (570 M-500 M)
    Paleozoic - Cambrian in the beginning was the frist time that Multicellular life forms flourished on Earth, and Pangaea was Formed.
  • Ordovician Period (500M- 435 M)

    Ordovician Period (500M- 435 M)
    Near the end of the period there were mass-extinction events that seriously affected planktonic forms like conodonts, graptolites, and some groups of trilobites (Agnostida and Ptychopariida, which completely died out, and the Asaphida, which were much reduced).
  • Silurian Period (435 M- 395M)

    Silurian Period (435 M- 395M)
    During this period, the Earth entered a long warm greenhouse phase, and warm shallow seas covered much of the equatorial land masses. Ice Glaciers retreadted to the South Pole.
  • Devonian Period (395 M- 345M)

    Devonian Period (395 M- 345M)
    The Devonian extinction crisis primarily affected the marine community, and selectively affected shallow warm-water organisms rather than cool-water organisms. The most important group to be affected by this extinction event were the reef-builders of the great Devonian reef-systems. The reasons for the Late Period extinction are still unknown.
  • Carboniferous Period (345M-280M (Mississippian, Pennsylvanian))

    Carboniferous Period (345M-280M (Mississippian, Pennsylvanian))
    Early Carboniferous land plants were very similar to those of the preceding Late Devonian, but new groups also appeared at this time. Fossil remains of air-breathing insects, myriapods and arachnids are known from the late Carboniferous, but so far not from the early Carboniferous. Their diversity when they do appear, however, shows that these arthropods were both well developed and numerous. Their large size can be attributed to the moistness of the environment.
  • Permian Period (280 M-225M)

    Permian Period (280 M-225M)
    Early Permian terrestrial faunas were dominated by pelycosaurs and amphibians, the middle Permian by primitive therapsids such as the dinocephalia, and the late Permian by more advanced therapsids such as gorgonopsians and dicynodonts.

    Time and Life of the Dinosuars. During this time Pangaea broke apart to the continent we know today. Era contains Cretaceous, Jurassic, and the Triassic Periods.
  • Triassic Period (225M-195M)

    Triassic Period (225M-195M)
    The Triassic climate was generally hot and dry, forming typical red bed sandstones and evaporites. There is no evidence of glaciation at or near either pole; in fact, the polar regions were apparently moist and temperate, a climate suitable for reptile-like creatures. Pangaea's large size limited the moderating effect of the global ocean; its continental climate was highly seasonal, with very hot summers and cold winters.
  • Jurassic Period (195M-136M)

    Jurassic Period (195M-136M)
    On land, large archosaurian reptiles remained dominant. The Jurassic was a golden age for the large herbivorous dinosaurs known as the sauropods—Camarasaurus, Apatosaurus, Diplodocus, Brachiosaurus, and many others.
  • Cretaceous Period (136M-65M)

    Cretaceous Period (136M-65M)
    The Cretaceous was a period with a relatively warm climate and high eustatic sea level. The oceans and seas were populated with now extinct marine reptiles, ammonites and rudists; and the land by dinosaurs. At the same time, new groups of mammals and birds as well as flowering plants appeared. The Cretaceous ended with one of the largest mass extinctions in Earth history, the K-T extinction, when many species, including the dinosaurs, pterosaurs, and large marine reptiles, disappeared.

    The cenozoic Era is the age of new life. During the Cenozoic, mammals diverged from a few small, simple, generalized forms into a diverse collection of terrestrial, marine, and flying animals, giving this period its other name, the Age of Mammals, despite the fact that birds still outnumbered mammals two to one. This Era contains the Periods; Tertiary and Quaternary.
  • Tertiary Period (65 M- 1.8M)

    Tertiary Period (65 M- 1.8M)
    Climates during the Tertiary slowly cooled, starting off in the Paleocene with tropical-to-moderate worldwide temperatures and ending before the first extensive glaciation at the start of the Quaternary.
  • Quaternary Period (1.8 M – Present)

    Quaternary Period (1.8 M – Present)
    The life and Earth we call home today.