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BITUMINOUS FAMILY. It is massive. It is dull, sometimes glimmering ; but this is owing to an intermixture of mica. The fracture is earthy, with a tendency to straight slaty. / It breaks into tabular pieces. The streak is shining. It feels rather meagre, and sometimes greasy. It is sectile. . It is very soft, inclining to friable. It is light. Chemical Characters. When exposed to heat, it burns with a flame; and when left some time exposed to a moist atmosphere, it becomes warm, and at length takes fire. Constituent Parts. Charcoal, ... 19.65 Sulphur, ... 2.85 Silica, ... 40.00 Alumina, - 16.00 Oxide of Iron, 6.40 Sulphate of Iron, - 1.80 Sulphate of Lime, 1.50 Magnesia, . . , 0.50 Sulphate of Potash, 1.50 Muriate of Potash, 0.50 Water, - 10.75 101.45 Klaproth, in Gehlen’s Journ. vi. 44. Geognostic Situation. It occurs frequently in beds of great magnitude in allu vial land, and sometimes also in the floetz-trap formation. Geographic