Miocene
Older epoch of the Neogene. Its name referred to a minority of fossil marine mollusc species considered identical with living species.
Language and route: English Miocene, coined with Greek combining elements. Charles Lyell’s English scientific coinage (1833), from Greek meíōn, ‘less’, and kainós, ‘new, recent’.
Literal gloss: less recent [living species]
The name and its history
Charles Lyell (with palaeontological work by G. P. Deshayes) · 1833
- What does the word literally mean?
- ‘Less recent’ did not describe the number of fossils nor mean that Miocene rocks are less recent than Eocene rocks. It referred to the proportion of fossil shell species still recognised as living, compared with the much larger proportion expected in the younger Pliocene. Lyell reported about 17–18% for his sample.
- What did the original author mean?
- Lyell’s ‘less recent’ referred to a minority of molluscan species considered still living, compared with younger Tertiary deposits.
- Why was the name needed?
- The European middle Tertiary needed separation from both older Eocene and younger Pliocene faunas.
- What evidence supported the original concept?
- Lyell listed 176 living species among 1,021 Miocene fossil shell species in 1833 (approximately 17%).
- How has geology changed the concept?
- Revisions in zoological taxonomy and correlation ended the percentages as formal boundaries; the named interval persists.
Further historical context
Charles Lyell published the term in Principles of Geology, vol. 3 (1833), drawing on Deshayes’s molluscan identifications from European Tertiary deposits, including Touraine, the Gironde and the Vienna Basin. It grouped strata judged intermediate by their fossil shell assemblages.
Lyell’s 1863 retrospective account conceded that subsequent collecting and revisions of species identifications made the neat percentage scheme unreliable as a formal means of delimiting the epoch.
Editorial qualification
Lyell 1833 original method compares the percentage of fossil marine mollusc species considered extant; this is a historical taxonomic assumption and not the present chronostratigraphic test.
Related names
Sources
- Charles Lyell (1833), Principles of Geology, vol. 3 (digitised text) — Original fossil-mollusc method and explicit Eocene/Miocene/Pliocene explanations
- Charles Lyell (1863), Geological Evidence of the Antiquity of Man, ch. 1 — Author’s retrospective explanation, limitations of percentages and changed meaning of Pleistocene
- International Commission on Stratigraphy, Chart 2026/06 — Current formal ranks and boundaries; not evidence of etymological first usage