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126 LIMESTONE FAMILY. Chemical Characters. It effervesces strongly with acids. Lime, 56.5 Constituent Parts. Chalk from Gallicia. Lime, - 47.00 Lime, - 53 Carbonic Acid, 43.0 Carbonic Acid, , 33.00 Carbonic Acid, 42 Water, 00.5 Silica, 7.00 Alumina, 2 Alumina, 2.00 Water, - 3 Bucholz, in Gehlcn’s Magnesia, Iron, 8.00 0.05 IS Journal, b. iv. s. 416. Kinran, Min. Itacjuet. vol. i. p. 77. Geognoslic Situation. It constitutes one of the newer floetz formations; is usually found in low situations, and frequently on sea coasts. It is stratified, and the strata in general are ho rizontal. It often contains flint, which is disposed either in interrupted beds in the chalk, or in globular, tuberose, or tabular masses imbedded in it. It abounds in organic remains, and these are principally of animals of the lower orders, such as echinites, belemnites, terebratulites, pin- nites, &c. These petrifactions, are either in the state of carbonate, or are converted into flint, which latter is by far the most frequent. It cannot be considered as a me talliferous formation, as it contains nothing but small imbedded portions of iron-pyrites. Two principal kinds of chalk occur in chalk districts: the one is named Hard, the other Soft Chalk; the hard chalk always occurs un dermost, is considerably harder than the other, and rarely contains petrifactions or flint; the soft chalk, on the con trary, rests upon the other, is softer, and abounds in flint and petrifactions. Geographic