SNAKE-STONE, a name sometimes applied to Water-of-Ayr stone (see Hone, vol. xii. p. 134). Certain stones reputed, on insufficient grounds, to possess efficacy as antidotes to snake-bites are known as snake-stones (see above, p. 192). The term is also popularly applied to ammonites and certain other fossils which, owing to their spiral shape, were formerly regarded as petrified snakes.