adj. & n.
--adj.
1. of the nature of chalk.
2 (Cretaceous) Geol. of or relating to the last period of the Mesozoic era, with evidence of the first flowering plants, the extinction of dinosaurs, and extensive deposits of chalk.
Usage:
Cf. Appendix II.
--n. Geol. this era or system.
Etymology: L cretaceus f. creta chalk