Page:Narrative of a survey of the intertropical and western coasts of Australia, Volume 2.djvu/647

 62 A PPF, Nm X. It. latter ease they have ome reeemldance to the trunks or root of tre.--A mass, which seems to have been of thi description, is stated to have come from a height of about two hundred and fifty feet above the sea, at Bald-head, on the South Coast of Australia. These specimens, however, do not really exhit any traces of organic structure; and so needy resemble the irregular stalacfifical concretions wodueed by the passage of calcareous or ferruginous so- lutions through sand *, that they are prolYably of the same origin; indeed the ceuVral cavity of the. stalactite still mains open in some' of the spedmens of this kind from �SweePs Island in the Oulf of Carpentaria. The specimens from Madeira, presented to the Geological Society by Mr. Bowdich, and described in his notes on that islandt, ap- pear upon examination to be of the same oharaeter.--But there is no reason to suppose that the trus of trees, as well as other foreign substances, may not b thus incrusted, since various foreign bodies even of artificial production, have been so found, Professor Bucklaud has mentioned specimen of concrete1 limestone from St. Helena, which contains the recent shell of'a blrd's egg**; and M. Ptron states that, in the coneretional limestone rock of the South Coast of I%w Holland, the trunh of trees occur, with the vegetable structure so distinot as to leave no doubt as to their nature i. ing hrough sand, like the roots of trees, are described by Captain Lyon as occuring in Africa--Lyon's Travels, Appeudix, p. 65. , Excursions in Madeira, 1825, p. 139, 140; and Bull des flciences Naturelies, vol. iv. p.
 * Tubuhu- concretions offerr,g/oaf matter, irregularly ramify-
 * 1: Oeol;"lh'ans. ,01. v. p. 479.

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