422 CLAY FAMILY. / Mi Chemical Characters. It is infusible before the blowpipe. Silica, Constituent Parts. 62.50 Silica, - . 58.0 Alumina, 00.75 Alumina, 5.0 Magnesia, 8.00 Magnesia, 6.5 Lime, 00.25 Lime, 1.5 Carbon, 00.75 Iron & Manganese, 9.0 Iron, 4.00 Water, 19.0 Klaproth. 100.0 Buchol*' Geognostic Situation. It occurs in beds in the third floetz gypsum, and co»' tains imbedded menilite. Geographic Situation. It has hitherto been found only in the gypsum forma' tion around Paris. Observations. It has been frequently confounded with Polier Slato from which it is distinguished by its greater specific g ra ' vity. 7. Police
