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Cambrian Period. - 570 to 500 MYA.
Earliest record of marine life. Triobites are dominant. -
Ordovician Period. - 500 to 435 MYA.
Echinoderms. (Starfish, sand dollars, sea urchin, and sea cucumbers.) Invertabrates are dominant, mollusks become abundant. Earliest fish are jawless and later armored fished and later jawed. -
Silurian Period. - 435 to 335 MYA.
Earliest terrestrial plants and animals. Eurypterids develope. -
Devonian Period. - 395 to 345 MYA.
Armored fish go extinct but abundance of several species of fish. Earliest amphibians and ammonties. -
Carboniferous Period. - 345 to 280 MYA.
Abundant sharks and amphibians. Large swamps and coal forming forests. Earliest reptiles, scale trees, and seed ferns. -
Permian Period. - 280 to 225 MYA.
Extinction of many types of marine animals including trilobetes. -
Triassic Period. - 225 to 195 MYA.
Earliest dinosaurs, adundant cycods, confiers. -
Jurassic Period. - 195 to 136 MYA.
Earliest birds and mammals abundant. Dinosaurs and ammonites. -
Cretaceous Period. - 136 to 65 MYA.
Age of reptiles. Earliest flowering plants. Climax of dinosaurs followed by their extinction. Great decline of brachiopods. Abundance of fish. -
Tertiary Period. - 65 to 1.8 MYA.
Earliest placental mammals, modern mammals, large running mammals. -
Quaternary Period. - 1.8 tp present MYA.
Large carnivores, neanderthais, humans, and masidons.
