"global chronostratigraphic units" Count: 5e; †118;85e (Eon) Phanerozoic Eon (541.0 Ma - present) Count: [*†*] 4e; †114;63e (Era) Cenozoic Era (66.0 Ma - present) Count: [*†*] 3e; †16;9e (Sub-era) †Tertiary Sub-era (66.0 - 2.58 Ma) see Period Tertiary Period (66.0 - 2.58 Ma) Count: [†*] †16;7e (Period) †Paleogene Period (66.0 - 23.03 Ma) Count: [†*] †8;3e (Epoch) †Oligocene Epoch (33.9 - 23.03 Ma) Count: [†*] †2 (Stage) †Chattian Stage (27.82 - 23.03 Ma) Count: -