Geological Time Scale

This table contains the geological time periods of the past 2.5 billion years on Earth to aid in understanding age immense age of these fossils.

(Ma = Mega-annum = 1,000,000 years)
EON ERA PERIOD EXTENT (Ma) DURATION (Ma)
Phanerozoic Cenozoic Quaternary 2.588–Present 2.588+
Neogene 23.03–2.588 20.4
Paleogene 66.0–23.03 42.9
Mesozoic Cretaceous 145.5–66.0 79.5
Jurassic 201.3–145.0 56.3
Triassic 252.17–201.3 50.9
Paleozoic Permian 298.9–252.17 46.7
Carboniferous 358.9–298.9 60
Devonian 419.2–358.9 60.3
Silurian 443.4–419.2 24.2
Ordovician 485.4–443.4 42
Cambrian 541.0–485.4 55.6
Proterozoic Neoproterozoic Ediacaran 635.0–541.0 94
Cryogenian 850–635 215
Tonian 1,000–850 150
Mesoproterozoic Stenian 1,200–1,000 200
Ectasian 1,400–1,200 200
Calymmian 1,600–1,400 200
Paleoproterozoic Statherian 1,800–1,600 200
Orosirian 2,050–1,800 250
Rhyacian 2,300–2,050 250
Siderian 2,500–2,300 200