I 529 ) 7 ELEVENTH SPECIES. Bituminous Marie Slate. Bituminofer Mergel Schiefer Werner. ® ! 'tuminofer mergel fchiefer, Wid. f. 526.—Bituminous ruarlite, Ki'rw. vol. 1. p. 103. — Bituminofer mergel fchiefer, Ejlntr, b. 2. f. 1035.—Id. Emm. b.' 1. f. 498 Schifto marno bituminofo, Nap. p. 363.—Le Schifte ma- r no bitumineux, Broch, t. 2. p. 574. \} External Characters. , Its colour is to be ccnfidered as intermediate be- t,v een greyifh and brownilh black. iVTaflive. Luftre either glimmering, gliftening, or (hining. ^rafture curved or ftraight flaty. fragments flaty. opaque. dually foft. . Somewhat mild. ^°t particularly brittle. Eafdy frangible. S^eak fhining, but produces no change of,colour. ^°t particularly heavy, approaching to light. Gcignostif