( 3°7 ) THIRD SUBSPECIES. Pipe Clay. Pfe i fenth on.—Werner. External Characters. Its colour is greyifh white palling into yellowilh white, and both fall Itrongly into grey. Occurs mafiive. Luftre glimmering. Fra&ure in the frnall, fine earthy; in the large, coarfe and fine grained uneven. Fragments indeterminately angular, fharp-edged. Streak Ihining. Intermediate between loofc and coherent, but more generally coherent. Adheres pretty Itrongly to the tongue. Feels rather greafy. Eafily frangible. Fight, palTing into not particularly heavy. R r 2 FOURTH >