Geo-chronology

GEO-CHRONOLOGY
Pre-Cambrian Late Precambrian Middle Precambrian Early Precambrian	Before 597 million years 597 to 2,400 million years 2,400 to 3,500 million years 3,500 to 4,600 million years

Palaeozoic Era Upper Palaeozoic Lower Palaozoic	235 to 597 million years 225 to 395 million years 395 to 597 million years
Subdivisions Cambrian Ordovician Silurian Devonian Carboniferous Permian	510 to 597 million years 460 to 510 million years 405 to 460 million years 360 to 405 million years 280 to 360 million years 235 to 280 million years

Mesozoic Era	64 to 235 million years
Subdivisions Triassic Jurassic Cretaceous	210 to 235 million years 135 to 210 million years 64 to 135 million years

Cenozoic Era Quaternary Period Tertiary Period	Present to 64 million years Present to 2 million years 2 to 64 million years
Subdivisions Palaeocene Eocene Oligocene Miocene Pliocene Pleistocene Holocene	54 to 64 million years 38 to 54 million years 26 to 38 million years 7 to 26 million years 2 to 7 million years 50,000 BC to 2 million years Present to 50,000