in the history of fossils, a substance much resembling the morocithus or French chalk, in many respects; but different from it in colour. The ancients found it in the Nile and in some rivers in Greece, and used it in medicine as an astringent, and for dislocations and ulcers of the eyes. At present it is common in Germany, Italy, and some parts of France, and is wholly overlooked, being esteemed a worse kind of morocithus. See Morocithus.