Definition of "gypseous" [gyp•se•ous]

• Of, relating to, or containing gypsum. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The oldest is the Gehannam Formation (ca 40-41 million years old) consisting of white marly limestone and gypseous shale and yielding many skeletons of archaic whales (archaeocetes), sirenians (sea cows), shark teeth, turtles, and crocodilians."
• "It probably represents a remnant of the old terrace which, like the Secondary gypseous formation, has been torn to pieces by the volcanic region to the east, and by the plutonic upheavals to the west."
• "This gypseous or Secondary formation was found to extend, not only over the adjacent hills, but everywhere along the road to"