Geological Time Scale

The following table describes Geological Time Scale in brief:

Era Period Period Age (as Million Years Ago – MYA) Major Events

Cenozoic

It is the Age of Mammals.

(about 65.5 MYA to Present Day)

Quaternary Holocene 0.01 MYA to present End of the Ice Age and dominance of human beings.
Pleistocene 1.6 MYA Ice Age began and the earliest human appeared.
Tertiary Pliocene 5.3 MYA Trace of human ancestors.
Miocene 23.7 MYA Abundance of grass.
Oligocene 36.6 MYA Dominance of mammals.
Eocene 57.8 MYA Extinction incident
Paleocene 65.5 MYA First large mammals evidenced.

Mesozoic

Age of Reptiles.

(about 245 MYA to 65.5 MYA

Cretaceous Extinction of Dinosaurs 144 MYA Flowering plants appeared.
Jurassic   208 MYA First birds appeared.
Triassi First Dinosaurs 245 MYA Reptiles were dominant and evidence of first mammals.

Paleozoic

(about 570 MYA to 245 MYA)

Permian Age of Amphibians 286 MYA  
Carboniferous   360 MYA First Reptile and large fish appeared.
Devonian Age of Fishes 408 MYA First land animal appeared.
Silurian   438 MYA First insects, land plants, & jawed fish appeared.
Ordovician   505 MYA Extinction incident evidenced.
Cambrian   570 MYA First fungi evidenced.

Precambrian

(about 4600 MYA to 570 MYA)

Proterozoic   2500 MYA First multicellular life appeared.
Achean   3800 MYA First unicellular life appeared.
Hadean Priscoan 4600 MYA Earth cooled and atmosphere and Ocean formed.