cretaceous
adj.adj. relating to the final period of the age of dinosaurs, which ended about 66 million years ago. It is famous for being the time when many well-known dinosaurs lived and then went extinct.
adj. relating to the final period of the Mesozoic Era, following the Jurassic and preceding the Paleogene. Often associated with the mass extinction event that concluded the age of non-avian dinosaurs.
The Tyrannosaurus rex lived during the late Cretaceous period.
Geologists identify Cretaceous rock layers by the presence of specific chalk deposits and marine fossils found worldwide.
The transition from the Cretaceous to the Paleogene is marked by a distinct sediment layer that suggests a catastrophic impact event fundamentally altered the planet's biosphere.
Specific use of cretaceous.
Typically used attributively to modify nouns like 'period', 'era', or 'strata'.