Lutites include a variety of fine-grained sedimentary rocks, including calcisiltite, calcilutite, claystone, mudstone, shale, and siltstone. It is equivalent to the term mudstone and the Greek-derived term pelite.[1][2] Lutite was first used in 1904 by Grabau,[3] who derived it from the Latin word for mud. He also proposed a number of prefixes to be used with and attached to "lutite" in order to designated various types of lutites.