Cretaceous (adjective)

1. Relating to or denoting the Cretaceous period, a geological time period from about 145 million to 65 million years ago.
2. Relating to or consisting of chalk or a rock similar to chalk.

Origin:

Derived from the latin word 'cretaceus' meaning 'chalky'.

Examples:

1. The cretaceous rock formations were characterized by their unique layers of chalk.
2. The cretaceous period was known for the diversification and evolution of dinosaurs.
3. The cretaceous environment was warm and tropical, with high sea levels and lush vegetation.
4. The cretaceous fossils provided valuable insights into the history of life on Earth.
5. The cretaceous rocks were used to study the geological and climatic changes of the period.