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39 2 derivatives. Siliceous Shiflus, penetrated with Limeftone. Prafiform Porphyry ofKarften, Le/ke S. 1811, Dark, fomewhat yellowilh grey. Luflre, o, except a very lew particlcs; tranf- parency, o. Fradture, fplintery; the grain very fine and clofe. Hardnefs, from 9 to 10 5 fp. gr. 2,578. 7 hough Karden rcekons it a fhiflofe norphyry, I can peiceive no traces of feifpar. The whicer fpots are evidently nothing elfe than femi-tranfpa- rent Iplinters. Pitchftone, penetrated with Opal. Lefke S. 295. Pearl grey, fomewhat refembling porcelanite. Luftre, filky, 2; tranfparency, 1. Seams penetrated with lumpsofcpal. Hardnefs, 8. brittle. Sp. gr. 1,970. Imbibes water flowlv. Hcated, it decrepirates ftrongly, and then whi- tens; at 148°,^ it remained a loofe powder. Granite, penetrated with Argillite. Leike S. 1883. Whitilh and purplifh grey. I.uftre, j. Tranlparency, o or o,^. Frafture, partly fplintery, and partly obfeurely foRted. Hardnefs, 8. very difficultly broken ; fp. pr. 2,670. The nrica and purplifli argillite are very per- ceptible. FIRST