in natural history, terrene spars, destitute of all brightness and transparency, formed into thin plates, and usually found coating over the sides of fissures, and other cavities of stones, with conglomerates of them of great extent, and of plain or botryoid surfaces.

Of these there are usually reckoned seven kinds: the first is the hard, brownish-white cibdelostracium, found in Germany; the second is the hard, whitish cibdelostracium, with thin crusts, and a smoother surface, found also in the Harts-forests in Germany; the third is the hard, pale-brown cibdelostracium, with numerous very thin crusts, found in subterranean caverns in many parts of England as well as Germany; the fourth is the white, light, and friable cibdelostracium, found also in Germany, but very rarely in any part of England; the fifth is the light, hard, pale-brown cibdelostracium, with a smooth surface, found in almost all parts of the world; the sixth is the whitish, friable, crustaceous cibdelostracium, with a rougher surface, frequent in Germany and England; and the seventh is the brownish-white friable cibdelostracium, with a dusty surface, found in several parts of Ireland, as well as Germany.