(mya = million years ago)

Phanerozoic Eon (544 mya to present)	Cenozoic Era (65 mya to today)	Quaternary (1.8 mya to today)        Holocene (11,000 years to today)        Pleistocene (1.8 mya to 11,000 yrs) Tertiary (65 to 1.8 mya)        Pliocene (5 to 1.8 mya)        Miocene (23 to 5 mya)        Oligocene (38 to 23 mya)        Eocene (54 to 38 mya)        Paleocene (65 to 54 mya)
	Mesozoic Era (245 to 65 mya)	Cretaceous (146 to 65 mya) Jurassic (208 to 146 mya) Triassic (245 to 208 mya)
	Paleozoic Era (544 to 245 mya)	Permian (286 to 245 mya) Carboniferous (360 to 286 mya)        Pennsylvanian (325 to 286 mya)        Mississippian (360 to 325 mya) Devonian (410 to 360 mya) Silurian (440 to 410 mya) Ordovician (505 to 440 mya) Cambrian (544 to 505 mya)         Tommotian (530 to 527 mya)
Precambrian Time (4,500 to 544 mya)	Proterozoic Era (2500 to 544 mya)	Neoproterozoic (900 to 544 mya)        Vendian (650 to 544 mya) Mesoproterozoic (1600 to 900 mya) Paleoproterozoic (2500 to 1600 mya)
	Archaean (3800 to 2500 mya)
	Hadean (4500 to 3800 mya)