CLAY

a soft rock, plastic when wet, of varying composition and character, the principal constituent being an extremely fine-grained hydrous aluminjum silicate such as kaolin and muscovite, decomposition products of felspars. Chlorite, derived from hornW.), blende, augite, or biotite also enters of into the formation of clays, together with calcite, epidote, quartz and other minerals reduced from their position as rock-constituents to a fine-grained state. 1797; clays are water-borne, and form in lakes and the sea, often in layers (mudstone). Some easily into leaflets or lamine, and are as shales, which frequently con organic products such as paraffin A few of the more important clay are red c., which forms in the parts of the ocean, and is the extensive deposit known; china c., consisting mainly of kaolin, is the purest c., and fire c. vary very much in constitution. Wind-borne, fine calcarec. is known as loe .