Tertiary

==Modern equivalents==
The Tertiary period lies between the [[Mesozoic|Mesozoic Era]] and the [[Quaternary|Quaternary Period]], although it is no longer recognized as a formal unit by the [[International Commission on Stratigraphy]].{{Citation needed|date=February 2024|reason=Citation needed for the entire above section, where none are provided}}

The span of the Tertiary is subdivided into the [[Paleocene]] (66–56&nbsp;million years [[Before Present|BP]]), the [[Eocene]] (56–33.9&nbsp;million years BP), the [[Oligocene]] (33–23.9&nbsp;million years BP), the [[Miocene]] (23–5.3&nbsp;million years BP) and the [[Pliocene]] (5.3–2.6&nbsp;million years BP), extending to the first stage of the [[Pleistocene]], the [[Gelasian]] Stage.<ref name="International Stratigraphic Chart">{{cite web |title=International Chronostratigraphic Chart |url=http://stratigraphy.org/ICSchart/ChronostratChart2013-01.pdf |publisher=International Commission on Stratigraphy |author=Cohen, K. M. |author2=Finney, S. |author3=Gibbard, P. L. |date=January 2013}}</ref><ref>{{cite book |author1=Ogg, James G. |author2=Gradstein, F. M. |author3=Gradstein, Felix M. |title=A Geologic Time Scale 2004 |url=https://archive.org/details/geologictimescal2004grad |url-access=limited |publisher=Cambridge University Press |location=Cambridge, UK |year=2004 |isbn=978-0-521-78142-8 |page=[https://archive.org/details/geologictimescal2004grad/page/n66 45] |chapter=1: Chronostratigraphy: Linking time and rock}}</ref><ref>{{cite web |title=On the Geologic Time Scale 2008 |url=http://www.stratigraphy.org/bak/gts2008.pdf |author1=Gradstein, Felix M. |author2=Ogg, James G. |author3=van&nbsp;Kranendonk, Martin |publisher=International Commission on Stratigraphy |access-date=18 December 2013 |page=5}}</ref><ref>{{cite book |author1=Vandenberghe, N. |author2=Hilgen, F.J. |author3=Speijer, R.P. |title=The Geologic Time Scale 2012 |year=2012 |publisher=Elsevier |location=Amsterdam |isbn=978-0-44-459425-9 |page=856 |edition=1st |editor1=Gradstein, Felix M. |editor2=Ogg, James G. |editor3=Schmitz, Mark D. |editor4=Ogg, Gabi M. |chapter=28: The Paleogene period |doi=10.1016/B978-0-444-59425-9.00028-7 |s2cid=129821669 |url=https://lirias.kuleuven.be/handle/123456789/320727}}</ref>