Years Ago	Era	Period	Epoch	Major Events
10,000	Cenozoic	Quaternary	Holocene	Extinction of many large mammals. Humans evolve
2 million			Pleistocene
5		Tertiary	[Pliocene]
25			[Miocene]
38			[Oligocene]
55			[Eocene]
65			[Paleocene]
144	Mesozoic	Cretaceous		Dinosaurs reach peak, go extinct. Primitive placental mammals
213		Jurassic		Marsupial mammals
248		Triassic		Egg-laying mammals
286	Paleozoic	Permian
360		Carboniferous
408		Devonian
438		Silurian
505		Ordovician		Invertebrates dominant; first fishes
570		Cambrian		Major diversification