Coralloid Carbonate of Lime

These curious chalky accretions are found plentifully in the loose marle at St. Maws, Cornwall, which abounds also with shells of various species, and is brought to Truro to be sent to different places for manure, being excellent for the adjoining lands. I have specimens from the Rev. H. Davies of North Wales. Their resemblance to corals has caused them to be mistaken for such; but on a careful exxamination, they are found to be only aggregations of calcareous earth, accumulated upon little nuclei, ramifying in the soft marle, and occasionally attracting other calareous particles, whih form fresh coats like the bark of a tree, and are not unlike the coats on the nuclei of the Ketton stone lengthened out, as the broken ends plainly show. They vary extremely in their forms, and when large are sometimes perforated on the outside, apparently by some marine insects; which may have contributed to the idea of the whole being of animal construction. Nature ever allotting certain bounds to every species of her productions, permits them to separate from one another in many nice and curious ways. Thus calcareous earth in this instance is separating from the clay in the form of opaque branching orals; in others we shall find different modes of separation or division of calcareous earth and other substances.

The small specimens are very much branched, and mostly white, but somewhat softer to the touch. The larger are often more coloured with iron, perhaps some animal substance, as the place in which they are found contains many dead shells. Sometimes they contain some salt, which is readily perceived by the taste, and remains after drying in the cabinet. Some have no saline taste.