marlstone
/ˈmɑrlˌstoʊn/
noun
- A type of rock that is a mixture of clay and calcium carbonate, often used in building or as a soil conditioner.
- Marlstone is sometimes crushed and spread on fields to reduce soil acidity.
- The old church was built from local marlstone, giving it a warm, earthy color.
- Hikers noticed the marlstone formations along the trail, layered with fossils.