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The Cenozoic is the geological era from 66.00 million years ago to the present. It comprises the Palaeogene, Neogene and Quaternary. Its subdivisions organize geological and climate records; their boundaries are defined stratigraphically, with numerical ages calibrated separately.^[ref]

The Mesozoic is the geological era from about 251.902 to 66.00 million years ago. It contains the Triassic, Jurassic and Cretaceous periods and precedes the Cenozoic. The chart gives uncertainty on the older numerical boundary.^[ref]

The Palaeogene is the geological period from 66.00 to 23.04 million years ago in the consulted chart. It contains the Paleocene, Eocene and Oligocene, preceding the Neogene within the Cenozoic.^[ref]