Encrinite

Example encrinite from the Silurian Brassfield Limestone of Ohio. Note different sizes of ossicles present.

Encrinites are a type of grain-supported bioclastic sedimentary rock in which all or most of the grains are crinoid ossicles. In older literature, the word is sometimes used to refer to individual fossil crinoids, but this usage is obsolete.

Distribution

Encrinites form in areas where disaggregated crinoid skeletal debris becomes concentrated, typically shallow warm euhaline seas. They are therefore very common in the Paleozoic rock record of North America and Eurasia, particularly during the Silurian through Early Devonian and the Early Mississippian, when high sea levels created widespread epeiric seas. Some encrinites are also known from the Jurassic of North America and Western Europe.