Jurassic
Middle Mesozoic period, after Triassic and before Cretaceous.
Language and route: French jurassique, based on Jura place name. From the Jura Mountains of the Franco-Swiss border region. Any deeper pre-Roman interpretation of Jura needs independent investigation.
Literal gloss: of the Jura Mountains
The name and its history
Alexandre Brongniart (period terminology) · 1829 (with Humboldt’s earlier Jura limestone)
- What does the word literally mean?
- French terrains jurassiques (‘Jura terrains’) was adopted for correlated strata, especially Jurassic limestones.
- What did the original author mean?
- The geological adjective commemorated correlated rocks of the Jura Mountains and neighbouring Europe.
- Why was the name needed?
- Geologists needed to recognise similar successions beyond one country even when local rock names differed.
- What evidence supported the original concept?
- Mapping, oolitic limestones and fossils from the Jura and correlated European regions supported the term.
- How has geology changed the concept?
- The Jurassic includes numerous global facies unlike Jura limestone; its naming predates Alberti’s ‘Trias’.
Further historical context
Alexander von Humboldt recognised ‘Jura limestone’ in comparisons with German rock successions around 1799. Alexandre Brongniart published the regional term terrains jurassiques in 1829, relating Jura rocks to comparable oolitic successions outside the mountain range.
The name therefore commemorates a place where a recognisable succession was studied and correlated—not an etymological place-name meaning, and not a claim that all Jurassic rocks are limestone.
Editorial qualification
The underlying name Jura is not securely glossed beyond its geographical referent.
Related names
Triassic · Cretaceous · Mesozoic · Facies
Sources
- ICS International Chronostratigraphic Chart, 2026/06 — Current name, rank and numerical boundaries
- Brongniart (1829), Tableau des terrains — Digitised original work associated with terrains jurassiques
- Alberti (1834), Beitrag zu einer Monographie ... — Digitised 1834 original: Buntsandstein, Muschelkalk and Keuper