mudstone
noun
mud·stone ˈməd-ˌstōn 
: an indurated shale produced by the consolidation of mud
Example Sentences
Recent Examples on the Web 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 Of all of the layers, researchers are most interested in the bottomset, made of sandstone and mudstone—and for good reason: as on Earth, any biology that emerged in the Jezero waters would most likely have settled into the mud and sand at the base. Jeffrey Kluger, Time, 7 Oct. 2021 The new angiosperm was named Gansufructus saligna, and all the fossil specimens were collected from the grayish green mudstone of the upper Zhonggou Formation, dating back to 112 million years ago. David Bressan, Forbes, 24 May 2021 Previous attempts to solve the puzzle did not take into account the fact that the crust can suck up water and lock it into hydrated minerals like clay and mudstone, Robin George Andrews reports for National Geographic. Theresa Machemer, Smithsonian Magazine, 19 Mar. 2021 The rover will range widely, performing science experiments and occasionally drilling small cores of mudstones and other rocks that could hold signs of ancient life. Daniel Clery, Science | AAAS, 21 Nov. 2019 See More
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 Of all of the layers, researchers are most interested in the bottomset, made of sandstone and mudstone—and for good reason: as on Earth, any biology that emerged in the Jezero waters would most likely have settled into the mud and sand at the base. Jeffrey Kluger, Time, 7 Oct. 2021 The new angiosperm was named Gansufructus saligna, and all the fossil specimens were collected from the grayish green mudstone of the upper Zhonggou Formation, dating back to 112 million years ago. David Bressan, Forbes, 24 May 2021 Previous attempts to solve the puzzle did not take into account the fact that the crust can suck up water and lock it into hydrated minerals like clay and mudstone, Robin George Andrews reports for National Geographic. Theresa Machemer, Smithsonian Magazine, 19 Mar. 2021 The rover will range widely, performing science experiments and occasionally drilling small cores of mudstones and other rocks that could hold signs of ancient life. Daniel Clery, Science | AAAS, 21 Nov. 2019 See More Word History
First Known Use
circa 1736, in the meaning defined above