Cretaceous

Cre·ta·ceous  (kr-tshs)

adj.

1. Of or belonging to the geologic time, system of rocks, and sedimentary deposits of the third and last period of the Mesozoic Era, characterized by the development of flowering plants and ending with the sudden extinction of the dinosaurs and many other forms of life. See Table at geologic time.

2. cretaceous Of, containing, or resembling chalk.

n.

The Cretaceous Period or its system of deposits.

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[From Latin crtceus, chalky, from crta, chalk, from Crta (terra), Cretan (earth).]

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cre·taceous·ly adv.

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Cretaceous

Adjective

Geol of the period of geological time about 135 million years ago, at the end of which the dinosaurs died out [Latin creta chalk]

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Cretaceous  (kr-tshs)

The third and last period of the Mesozoic Era, from about 144 to 65 million years ago. During this time the supercontinent Pangaea continued to split up, with modern-day South America and Africa splitting apart, the Atlantic Ocean widening, and India disconnecting itself entirely from the other landmasses to which it was attached. Dinosaurs continued to be the dominant terrestrial animals, but many insect groups, modern mammals and birds, and the angiosperms (flowering plants) also first appeared. The Cretaceous Period ended with a mass extinction event in which about 75 percent of all species, including marine, freshwater, and terrestrial organisms, became extinct. See Chart at geologic time.

Thesaurus

Noun	1.	Cretaceous - from 135 million to 63 million years ago; end of the age of reptiles; appearance of modern insects and flowering plants Cretaceous period Age of Reptiles, Mesozoic, Mesozoic era - from 230 million to 63 million years ago
Adj.	1.	cretaceous - abounding in chalk
	2.	Cretaceous - of or relating to or denoting the third period of the Mesozoic era