200 CLAY GENUS. THIRD SPECIES. Pitchftone. Pechftein.—Werner. Id. Wid. p. 332.—Pitchftone, Kirw. vol. r. p. 292—*'' Pechftein Ejlner, b. 2. f. 435. Id. Emm. b. 1. f- Pietra picea, Nap. p. 203 Piffite var. h. Lam■ *• 2 ’ p. 162—La Pierre de Poix, Broch. t. 1. p. 353-—^ e * trofilex refiniforme, Hauy, t. 4. p. 386. •• ry. / •>' External Char after s. ’ ‘ Its colours are black, green, brown, red, and dom grey. Of black it prefents the following varie- ties: greenilh, greyilh, and brownilh black. Frotn greeriilh black it pafles through blackilh green into mountain green, afparagus green, leek green, ohve green, and oil green. From olive green it pa^ e ® jnto liver brown, yellowilh and reddilh brown, alU further into light blood and brick red. I he only varieties of grey are fmoke and dark afh g re y» an ^ fometimes a kind of grey which pafles into brown- has fometimes a blueifh colour. r I