resembling or containing chalk.
(initial capital letter) noting or pertaining to a period of the Mesozoic Era, from 140 million to 65 million years ago, characterized by the greatest development and subsequent extinction of dinosaurs and the advent of flowering plants and modern insects.
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
1665–70; < Latin crētāceus, equivalent to crēt ( a ) chalk, clay ( cf. crayon) + -āceus -aceous; the geological period was defined from the chalk beds of SE England and associated formations
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Earliest known mammalian stapes from an early cretaceous eutriconodontan mammal and implications for evolution of mammalian middle ear.
From Nature • Nov. 12, 2017
Five miles below sea level, and beneath a shifting layer of cretaceous salt deposits, the discoveries have been estimated at 50 billion to 100 billion barrels.
From BusinessWeek • May 10, 2012
Princeton paleontologists under the leadership of Dr. Glenn L. Jepsen. digging in a cretaceous formation near Red Lodge in southern Montana, found some old broken eggs.
From Time Magazine Archive
He appears, however, to have confounded strata of very different ages, tertiary rocks with cretaceous and jurassic.
From The Thistle and the Cedar of Lebanon by Risk Allah, Habeeb
Consequently, another range of mountains, at the base of which cretaceous rocks may lie in horizontal stratification, may have been elevated, like the chain A, fig.
From Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology by Lyell, Charles, Sir
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