Epoch (geology)

An epoch in geology is a part of a period. Thus the Cainozoic era is now divided into three periods, the Palaeogene, the Neogene and the Quaternary. These are finally broken down into these epochs: Palaeocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene and Holocene.International Commission on Stratigraphy International Commission on Stratigraphy There are alternate spellings for some terms: the prefix 'Palaeo' is written 'Paleo' in American English. both versions are correct. 'Cainozoic' may be spelled 'Cenozoic'. 

The Tertiary, now not used ('deprecated'), included the Palaeogene and Neogene. That is why the last period is called the Quarternary, and there was a big debate about that, too. These decisions are made by the International Union of Geological Sciences (IUGS). This organisation runs an International Commission on Stratigraphy, which decides how we should name geological strata and stages.International Committee on Stratigraphy International Commission on Stratigraphy  They describe their work as follows:
"[Our] primary objective is to precisely define global units (systems, series, and stages) of the International Chronostratigraphic Chart... [These] are the basis for the units (periods, epochs, and age) of the International Geologic Time Scale."
 Mesozoic
 Triassic
 Lower Triassic
 Middle Triassic
 Upper Triassic
 Jurassic
 Lower Jurassic
 Middle Jurassic
 Upper Jurassic
 Cretaceous
 Lower Cretaceous
 Upper Cretaceous
 Cainozoic
 Palaeogene
 Palaeocene
 Eocene
 Oligocene
 Neogene
 Miocene
 Pliocene
 Quaternary
 Pleistocene
 Holocene

 References 

Category:Geological periods