The Collaborative International Dictionary
Cretacic \Cre*tac"ic\
Cretaceous acid, an old name for carbonic acid.
Cretaceous formation (Geol.), the series of strata of various kinds, including beds of chalk, green sand, etc., formed in the Cretaceous period; -- called also the chalk formation. See the Diagram under Geology.
Cretaceous period (Geol.), the time in the latter part of the Mesozoic age during which the Cretaceous formation was deposited, and at the end of which the dinosaurs died out. See Cretaceous.
Usage examples of "cretaceous period".
That's one reason I know this is the Paleocene and not the Cretaceous period.
Or the terrible sandstorms thought by some scientists to have occurred during the Cretaceous Period in what today is Mongolia, burying dinosaurs where they crouched, turned away from the terrible wind.
The fossil record implicates the end of the Cretaceous period, 65 million years ago, as 'D-Day'.
Dinosaurs had died out in the Cretaceous period, sixty-five million years ago.
The world moved into the Jurassic period, but everyone's seen the movie, so on to the Cretaceous period, about 140 million to 65 million years ago.
We humans have already precipitated extinctions of species on a scale unprecedented since the end of the Cretaceous Period.