in natural history, a substance concerning the nature of which there has been much dispute. Some maintain it to be a petrified animal; others will will have it to be a fossil, &c. Linnaeus refers the belemnites to the class of shells with several cells. The shape of the belemnites is sometimes conical, sometimes cylindrical; and they commonly consist of a black horny kind of substance. Their length is from two to eight inches; and their diameter from the sixth part of an inch to two or three inches. The inward part consists of rays; and there is generally a cell at the large end, and a furrow running from top to bottom. Dr Plott says, that when scraped or burnt, they smell like horn. They are generally hollow about an inch deep, and filled with gravel. Their colour is various; some are ash-coloured, others bluish. They are commonly found in gravel-pits. See Plate LI., fig. 21.