Marl, << mahrl, >> is the common name for calcareous mudstone, a type of rock that consists of almost equal amounts of clay and calcite or dolomite. It is a sedimentary rock, a layered rock formed by the accumulation of other rocks and mineral fragments. Many marls form at the edges of freshwater lakes and contain fossils.
People use marl in various ways, depending on the impurities present. Greensand marl has much phosphorus and potash, and farmers use it as a fertilizer. Shell marl contains many fossil shells and is used as a decorative stone.
