Cretaceously
Pronunciation : Cre*ta"ceous*ly
Part of Speech : adv.
Definition : Defn: In a chalky manner; as chalk.
Source : Webster's Unabridged Dictionary, 1913
Merriam-Webster's Everyday Language Reference Set: Includes: The Merriam-Webster Dictionary, The Merriam-Webster Thesaurus, and The Merriam-Webster Vocabulary Builder