mudstone

[muhd-stohn]

noun Geology.

a clayey rock with the texture and composition of shale but little or no lamination.

Origin of mudstone

First recorded in 1730–40; mud + stone

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for mudstone

mudstone

noun

a dark grey clay rock similar to shale but with the lamination less well developed

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

mudstone in Science

mudstone

[mŭd′stōn′]

A fine-grained, dark gray sedimentary rock consisting primarily of compacted and hardened silt and clay, similar to shale but without laminations. The proportions of silt and clay in mudstone are approximately equal.