Geological Time Scale

The history of the earth is classified with the following geological time scales. There are a wide variety of accepted dates.

Eon	Era	Period	Epoch	Years Before Present
Archean				4.6 - 2.5 billion
	Hadean			4.6 - 3.8 billion
	Isuan			3.8 - 3.5 billion
	Swazian			3.5 - 2.8 billion
	Randian			2.8 - 2.5 billion
Proterozoic				2.5 billion - 570 million
	Huronian			2.5 - 2.2 billion
	Animikean			2.2 - 1.7 billion
	Riphean			1.7 billion - 800 million
	Sinian			800 - 570 million
Phanerozoic				570 million - present
	Paleozoic			570 - 245 million
		Cambrian		570 - 500 million
		Ordovician		500 - 435 million
		Silurian		435 - 410 million
		Devonian		410 - 380 million
		Carboniferous		380 - 290 million
		Permian		290 - 240 million
	Mesozoic			245 - 65 million
		Triassic		240 - 205 million
		Jurassic		205 - 138 million
		Cretaceous		138 - 65 million
	Cenozoic			65 million - present
		Tertiary		65 - 1.6 million
			Paleocene	65 - 55 million
			Eocene	55 - 38 million
			Oligocene	38 - 24 million
			Miocene	24 - 5 million
			Pliocene	5 - 1.6 million
		Quaternary		1.6 million - present
			Pleistocene	1.6 million - 10,000
			Holocene	10,000 - present