Cretaceous
Last Mesozoic period, following Jurassic and ending at 66 Ma.
Language and route: French geological crétacé, ultimately Latin. French crétacé, from Latin crēta, ‘chalk’; scientific English Cretaceous followed.
Literal gloss: chalky
The name and its history
J.-B. d’Omalius d’Halloy · 1822
- What does the word literally mean?
- The name alludes to the widespread white chalk facies of parts of Europe, especially the Paris Basin and neighbouring territories.
- What did the original author mean?
- The Latin/French chalk-derived designation referred to chalk-bearing terrain in parts of Europe.
- Why was the name needed?
- Chalk successions required a recognizable unit within expanding European geological maps and regional correlations.
- What evidence supported the original concept?
- Chalk, associated marls/sands and their diagnostic fossils underpinned early usage.
- How has geology changed the concept?
- Many Cretaceous strata contain no chalk; the name identifies geological time rather than a universal rock type.
Further historical context
Jean-Baptiste d’Omalius d’Halloy used Terrain Crétacé on his 1822 geological map; recent historiography notes that this map legend was a foundation of the system, rather than there being a single definitive descriptive founding paper.
The name was extended beyond the chalk itself to sands, marls and many globally correlated facies. Global chronostratigraphy is now based on boundaries and correlation, not whether chalk occurs.
Editorial qualification
No known contested attribution identified in this pass; source checks remain subject to peer review.
Related names
Sources
- ICS International Chronostratigraphic Chart, 2026/06 — Current name, rank and numerical boundaries
- Hart et al. (2025), Introduction to the Cretaceous System — 1822 use of Terrain Crétacé by d’Omalius d’Halloy
- Conybeare & Phillips (1822), Outlines of the Geology of England and Wales — Digitised early classification; Medial or Carboniferous Order