SL.ft.TY POTTERS CLAY. 417 Second Kind. Slaty Potters-CIay. Schiefriger Topferthon, Werner. Schiefriger Topferthon, Steffens, t>. i. s. 200. Id. Lenz, b. ii. s. 554. External Characters. ' Its colour is bluish-grey, which sometimes passes into Pearl-grey, also smoke-grey. It occurs massive. The lustre of the principal fracture is glistening; the cross fracture dull. The principal fracture is imperfect slaty; the cross fracture fine earthy. It agrees in other characters with the preceding kind, being only more greasy to the feel. Geognostic Situation. It occurs in considerable beds in alluvial districts, along *r>th Earthy Potters-CIay. Third Subspecies. Variegated Clay. Hunter Thon, Werner. Bunter Thon, Steffens, b. i. s. 200. Id. Lenz, b. ii. s. 554. External Characters. pe^f co ^ ours are yellowish-white, reddish-white, flesh and ea c -blossom red, ochre-yellow, and yellowish-brown. I. i-ll These