ed its natural quantity of animal matter unaltered, whereas all of these now before us are thoroughly mineralized,—that is, the whole of the animal substance has in them been replaced by earthy matter, which proves to be of different quality in each; the following are the results of a hasty chemical examination of them.
No. 1.—In this specimen, the osseous part has become quite friable and white, as if it had been burnt, while the membranous fibre has been replaced by crystals of carbonate of lime of a delicate greenish hue: I separated a small portion of these crystals with care, and analysed them by solution in muriatic acid, in a glass measure over mercury: the carbonic acid disengaged was equivalent to 82.5 per cent. of carbonate of lime; the remainder was phosphate, which had adhered to the crystals. The white part treated in a similar way gave,
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Carbonate of lime, 14.0
Phosphate of lime dissolved with ditto and precipitated by ammonia, 85.5
Needle-form silicious fibres evidently deposited by infiltration, 0.5
100.0
There was no trace of animal matter.
No. 2.—The appearance of this bone is more compact than the first: the membranous texture has in some places taken a fine peuce color, and in others a green tinge: treated as before, or rather calculating the carbonate from the weight of gas expelled; and the phosphate from the amount dissolved by the acid, in excess of the carbonate, its composition was,
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Carbonate of lime, 16.0
Phosphate of lime, 71.0
Skeleton of silex more complete than the first; color jasper red, 13.0
100.0
No. 3.—This specimen has become almost entirely silicified; it scratches glass; does not effervesce with acids, and only yields one per cent. to boiling nitric acid: it is unaltered before the blow-pipe.
Before Mr. Royle went home, he gave me a fragment of porous calcareous stone, found by him somewhere on the banks of the Jamna, which he imagined to be fossil bone: I did not then minutely examine it, but I am now happy to confirm his opinion, and only regret, that I have not the locality to pursue the inquiry further: the animal matter of this specimen, No. 4, is gone, and is replaced only by loose dirt: the composition of the osseous part is,
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Carbonate of lime, 18.0
Phosphate of lime, 80.0
Brown ochreous residue, 2.0
100.0
