mud·​stone ˈməd-ˌstōn How to pronounce mudstone (audio)
: an indurated shale produced by the consolidation of mud

Example Sentences

Recent Examples on the Web Its robotic arm drilled a 2.5-inch borehole in mudstone bedrock. Adam Hadhazy, Discover Magazine, 9 Dec. 2013 Galestro is a crumbly marl (mudstone) made of layered limestone and sandstone. Joseph V Micallef, Forbes, 18 Dec. 2022 Salt crystals left impressions in 3.5 billion-year-old mudstone, part of WesternAustralia's Pilbara Craton. Gemma Tarlach, Discover Magazine, 11 June 2019 The mudstone and carbonate sediment around the specimens indicates that the site had been deep underwater. Max G. Levy, WIRED, 19 Dec. 2022 Perseverance has, for example, identified a 3-foot-wide mudstone, dubbed Wildcat Ridge, that contains organic compounds and likely formed billions of years ago as mud and sandy sediments were deposited in an evaporating lake. Denise Chow, NBC News, 15 Sep. 2022 It was embedded in two large chunks of sandstone and mudstone unearthed in 2019 from a construction project in the Otay Ranch area of San Diego County. Pam Kragen, San Diego Union-Tribune, 2 May 2022 Located between layers of purplish-red mudstone and grayish-yellow sandstone were several armor plates and the shoulder, thigh, feet, back and rib bones of a stegosaur. Ashley Strickland, CNN, 3 Mar. 2022 Formed of mudstone dating to the Middle Triassic epoch, the rock could not have originated in the Krapina rockshelter, which is composed of sandstone. David W. Frayer, Scientific American, 1 Feb. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mudstone.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

First Known Use

circa 1736, in the meaning defined above

Time Traveler
The first known use of mudstone was circa 1736

Dictionary Entries Near mudstone

Cite this Entry

“Mudstone.” Dictionary, Merriam-Webster, Accessed 7 Feb. 2023.

More from Merriam-Webster on mudstone

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

The Great British Vocabulary Quiz

  • union jack speech bubble
  • Named after Sir Robert Peel, what are British police called?
Spell It

Hear a word and type it out. How many can you get right?

Solve today's spelling word game by finding as many words as you can with using just 7 letters. Longer words score more points.

Can you make 12 words with 7 letters?