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liquated, altered from its original State and Conſiſtence, and afterwards indurated again, It will melt, as Stones, with fuſible and foſſile Subſtances; and is ſoftened, and made into Bricks: Theſe are of various Kinds, and compoſed in various Manners, but are all made by moiſtening and burning.
other Foſſils: The other they have in common with Stones; and, indeed, with almoſt all other foſſile Bodies whatever. It was impoſſible for our Author to have known this, unleſs he had had our Aſſiſtances. But we find by Experiments with powerful Burning-glaſſes, that in a manner all foſſile Subſtances, as well as Earths, are fuſible and vitrifiable.
Earths, determinately ſpeaking, are opake Bodies, diffuſible by Water, and vitrifiable by extreme Heat; friable when dry, not inflammable, and generally inſipid to the Taſte: Not that theſe are certain, univerſal Characteriſtics, and liable to no Exceptions. Whatever may be the Caſe in the Vegetable and Animal Kingdoms, it is the Misfortune in the Study of foſſile Bodies, that ſuch has been the Confuſion and Intermixture of their conſtituent Particles at the general Deluge, that there are none ſuch to be eſtabliſhed in them; for there are ſo many heterogene Particles, of a thouſand different Kinds, mixed even with the ſame Foſſil in different Places, that there is no determining to any Certainty, even its Manner of Variation from its pure State. What I have given may paſs, however, for a general Character of what, in Treatiſes of Foſſils, we mean by the Word Earths; which may be afterwards diſtinguiſhed into Clays, Ochres, Boles, Marles, Chalks, and Loams. Sand, and the common vegetable Mould, which ſome give a Place in the Catalogues of Earths, have of right no Buſineſs among them; for the firſt is only either a ſmaller kind of Gravel, conſiſting of an infinite Number of ſmall Pebbles of different Shapes and Colours; or the conſtituent Particles of the Stone of Strata or other Bodies accidentally looſe: and the latter owes its preſent Mode of Exiſtence, in a great meaſure, to putrifed animal and vegetable Subſtances of a
