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The discordance appears to be removed by the assumption of indefinite periods for the six days of creation: an interpretation adopted by many learned and pious men, and which derives confirmation from innumerable circumstances agreeing with the important fact of certain fossils being found to be peculiar to particular strata; and especially from the remains of widely differing races of animals being found in such situations as evince that their creation must have taken place at very distant periods.

For the several imperfections in this work, which may have escaped the author's attention, he craves indulgence; hoping that they will not be found of such importance as to render the wish too presumptuous of having it considered as a humble subsidiary to that scientific and most valuably comprehensive work, Outlines of the Geology of England and Wales,by the Rey. W. D. CONYBEARE and W. PHILIPS.

LONDON, July 1822.

ERRA T A.

11,

Page 8, live 5, for “ combustible read“ incombustible."

3, for “ disposed" read“ arranged”
57, 36, for “ pappillosum” read “ papillosum.”
64, five lines from the bottom, for “resepores” read“ retepores."
71, last line, for “ formation' read “ formations."
77, line 25, for concluding sentence, read “ tortuous vallies which

held the polypes, and thus separated them."
79, 14, for “ Explanariæ" read “ Explanaria."
101, 5, dele&."
147, last line, insert

after “smooth."
170, Ime 13, dele " considerable."
297, six lines from the bottom, for “ similiarity" read “ similarity.”
302, line 14, for « and” read“ or.”
302, 16, dele « in.”
303, 28, for “ as" read “ than."

The reader is requested to observe also, that the figure intended to illustrate

Alveolites incrustans, page 66, and for which a reference is given to Pl. II, fig. 5, will be found at Pl. X, fig. 11; and that it having been thought necessary to give an illustrative figure of Tubipora unastomosans, page 71, it is introduced Pl. IX, fig. 10.

OUTLINES

OP

OR Y CTO LOG Y.

Oryctology is the science which enquires into the nature, origin, and formation of those bodies which possess the figures, markings, or structure of vegetables or animals, whilst their substance evinces their having been preserved through many ages, by certain changes effected in subaqueous or subterranean situations*.

The substances of which these bodies are formed being generally of a mineral nature, the term FOSSILS is applied to them, as declaratory of their having been dug from subterranean situations. They have also been termed adventitious, extraneous, or secondary fossils, to distinguish them from those fossils or original mineral substances which are found in their native state and situations. But as the term fossil, alone, declares these bodies, bearing the obvious and characteristic marks of vegetable or animal organization, to have been

* The term Oryctology is liable to the objection of not being sufficiently confined, it including, in fact, every substance dug out of the earth; the term Fossil, also, is exposed to the same objection: in excuse for their employment, it must be observed, that this language was formed, and these terms were adopted and had received the stamp of authority from usage, wbilst utter ignorance prevailed respecting the nature of the substances to which they were applied. Either, then, the best of these terms must be admitted, a new vocabulary be formed, or perpetual periphrasis be had recourse to: the first has been preferred.

obtained from the mineral kingdom, the employment of any of these epithets appears to be unnecessary.

By whatever mode organic remains, in subterranean or subaqueous situations, may be preserved from resolution of their substance for a considerable time, it is obvious that they must be liable to be impregnated with whatever matters may be held in solution in the fluids with which they may be thus imbued. From this source mineral matters may be deposited, by intromission, into the original interstices and cavities of the organic body; or may, by substitution, fill the spaces which have been produced by the partial removal of the original organic substance; or lastly, may, by impregnation and consolidation of the chemically altered organic matter itself, produce the several earthy or metallic fossils.

The earthy substances which enter into the composition of fossils, or, as in these cases they may be termed petrifactions, are chiefly of the calcareous, siliceous, and argillaceous kinds, in different states, and in various mixtures. The most common of the calcareous genus are the several species and varieties of carbonates; limestone, marble, stinkstone, chalk, spar, oolite, &c. Fluate of lime sometimes occurs as the matrix, and, very rarely, it forms the substance of fossils. Sulphate of lime, though sometimes found crystallized in their cavities, has not been mentioned as forming the substance of fossils. Sulphate of barytes, or baroselenite, is said sometimes to form the substance of fossils, but the instances are very rare. Silex enters, in different combinations, into the composition of fossils: quartz, chert, agate, calcedony, jasper, flint, pitchstone, and semiopal, have all been found forming their substance or constituting the masses in which they have been contained. Alumine frequently also enters into the composition of fossils, as well as of their containing matrices; clay frequently fills their cavities, and forms the beds in which they are found. Bituminous shale, slate, and argillaceous iron stone, often contain fossils. Fullers'-earth has sometimes, though rarely, been found to contain some particular fossils. The nuclei of fossil shells have been formed of hornblende, and both vegetable and animal fossils have been found in substances designated as basalt, wacké, and trap.

The metals which most commonly contribute to the formation of fossils are iron and copper, rarely lead or zinc, and still more rarely silver; they generally exist in the form of carbonates or of sulphurets. The carbonates as well as the sulphurets of iron are chiefly found in vegetable remains. Ligneous fossils of this species present a very curious fact: although the texture of the wood appears to be nearly unaltered, its substance has been so intersected by the crystallizations, that on decomposition it is resolved into an impalpable efflorescence.

The specimens of wood which have been mineralized by copper sometimes possess a considerable degree of beauty, from the brilliant colours of the malachite which enters into their composition. The sulphuret of lead, galena, has been found in fossil wood; and blende, the sulphuret of zinc, has been found, with quartz crystals, investing fossil shells. Silver is said to exist in a fossil somewhat resembling the ears of corn, found in the mines of Frankenberg, in Hesse.

Casts or nuclei of organic remains are formed by different mineral substances filling their cavities, and thus taking the impressions of their internal forms and markings. Impressions of the external surface are formed by investment by the surrounding matrix and by its subsequent induration. After this is accomplished, and the original substance removed, a cavity or mould is left in the matrix corresponding in its figure

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