Geological Time Exposed By MsHayesTCAH 100 Cambrian Period Cambrian Period - part of Paleozoic Era Period: 100 to 500 Paleozoic Era Period: 500 to Mar 8, 700 Mesozoic Mar 8, 600 Jurassic Period Part of the Mesozoic Era Mar 8, 700 Cretaceous Period Cretacious Period part of Mesozoic Era Period: Mar 8, 700 to Mar 8, 800 Cenozoic Era Contains Paleogene and Neogene Periods 70 million years to present.