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disunion of concrete bodies, and powerfully cooperate with that wonderful fluid which alternately forms and unforms; which, as some affirm, creates, decomposes, and regenerates all nature.

The immediate effects of water in the shape of rain is to depress the mountains. But the materials which compose them must resist in proportion to their hardness; and hence we ought not to be surprised at meeting occasionally with peaks, which have stood firm amidst the wreck of ages, and still remain to attest the original level of the mountainbreadths which have disappeared. These primitive rocks, alike inaccessible to the assault of time and to that of the once animated beings which cover the less elevated heights with their relics, may be considered as the origin of streams and rivers. The water which falls on their summits flows down in torrents by their lateral surfaces. In its course it wears away the soil upon which it is incessantly acting. It hollows out channels of a depth proportioned to its rapidity, its quantity, and the hardness of the rock over which it passes, and at the same time carries along with it fragments of such stones as it loosens in its progress.

These stones, rolled by the water, strike together, and mutually break off their projecting angles; and hence we obtain collections of rounded flints which line the beds of rivers, and of smaller pebbles which the sea is perpetually throwing upon the shores, often incrusted with a gravelly or calcareous edging. The powder which is produced by the rounding of the flints, or is washed down from the mountains, frequently stagnates, forms a paste, and agglutinates into fresh masses of the rocky matter of which it

consists; often embedding flints and other materials, and constituting compound substances known by the name of pudding-stones and grit-stones, which chiefly differ from each other in the coarseness or fineness of their grains, or in the cement which connects them. And if the water be loaded, as it often is, with minutely-divided particles of quartz, it will proceed to crystallize whenever it becomes quiescent; and will form stalactites, agates, carnelians, rock crystals, plain or coloured, according as it is destitute of, or combined with, any colouring material: and if the material with which the water be impregnated be lime instead of quartz, the crystallization will be calcareous alabaster, or marble.

Many of the earths are now known to be metallic oxydes, and all of them are suspected to be so: and hence a degree of heat capable of fusing them, and depriving them of the oxygene which gives them their oxyde form, will necessarily convert them into their metallic state. That such currents of heat, from electricity and other causes, are occasionally, and perhaps in different places perpetually, existing beneath the surface of the earth, the Neptunian is as ready to admit as the Plutonic geologist: and hence the origin of metallic minerals, of mines, ores, ochres, and pyrites.

The decomposition of animal and vegetable matter contributes largely, moreover, in the view of the system now before us, to the changes which the globe is perpetually sustaining. The exuvia of shell and coral animals is perpetually adding to the mass of its earths, and laying a foundation for new islands and numerous beds of limestone, in which we very often perceive impressions of the shells from

which the soil has originated. On the other hand, we observed numerous quantities of vegetables, both submarine and superficial, heaped and deposited together by currents or other causes constituting distinct strata, which progressively become decomposed, lose their organization, and confound their own principles with those of the earths. Hence the origin of pit-coal, and secondary schists or slates; to which, however, the decomposition of animal substances has also largely contributed. Hence, too, the formation and extrication of a variety of acids and alkalies, which have essentially administered to the actual phænomena of the face of the earth.

The action of volcanoes has contributed much in all ages, and is still contributing in our own, to the present state of the earth's surface. We have daily proofs of the mountains which it has elevated, and have already noticed it as one source of the nume rous islands that stud the face of the ocean; and we have just adverted to the subterranean agencies of electricity, heat, water, and other gases and fluids which form its fuel. But the operation of volcanoes is more limited and local than that of the preceding agents. "They accumulate substances," says M. Cuvier, 66 on the surface that were formerly buried deep in the bowels of the earth, after having changed or modified their nature or appearances, and raise them into mountains; but they have never raised up nor overturned the strata through which their apertures pass, and have in no degree contributed to the elevation of the great mountains which are not volcanic."

Inundations of seas and rivers have also, from

time to time, added their tremendous force; but there is no ground for concluding that any catastrophe of this kind has been universal for the last four thousand years; nor, in fact, that such an event has ever occurred more than once since the earth has been rendered habitable.

In examining, then, the merits of the antagonist systems of geology before us, the Plutonic is perhaps best entitled to the praise of boldness of conception and unlimited extent of view. It aspires, in many of its modifications, not only to account for the present appearances of the earth, but for that of the universe; and traces out a scheme by which every planet, or system of planets, may be continued indefinitely, and perhaps for ever, by a perpetual series of restoration and balance.

With this system the Neptunian forms a perfect contrast. It is limited to the earth, and to the present appearances of the earth. It resolves the genuine origin of things into the operation of water; and while it admits the existence of subterranean fires to a certain extent, and that several of the phænomena that strike us most forcibly may be the result of such an agency, it peremptorily denies that such an agency is the sole or universal cause of the existing state of things, or that it could possibly be rendered competent to such an effect.

More especially should we feel disposed to adhere to this theory, from its general coincidence with the geology of the Scriptures. The Mosaic narrative, indeed, with bold and soaring pinions, takes a comprehensive sweep through the vast range of the solar system, if not through that of the universe; and, in its history of the simultaneous origin of this

system, touches chiefly upon geology, as the part most interesting to ourselves; but so far as it enters upon this doctrine, it is in sufficiently close accordance with the Neptunian scheme,—with the great volume of nature as now cursorily dipped into. The narrative opens, as I had occasion to observe in the lecture on Matter and a Material World, with a statement of three distinct facts, each following the other in a regular series, in the origin of the visible world. First, an absolute creation, as opposed to a mere remodification, of the heaven and the earth, which constituted the earliest step in the creative process. Secondly, the condition of the earth when it was thus primarily brought into being, which was that of an amorphous or shapeless waste. And, thirdly, a commencing effort to reduce the unfashioned mass to a condition of order and harmony. "In the beginning," says the sacred historian, "God CREATED the heaven and the earth. - And the earth was WITHOUT FORM AND VOID: and darkness was upon the face of the deep (or abyss). — And the Spirit of God MOVED upon the FACE OF THE WATERS."

We are hence, therefore, necessarily led to infer that the first change of the formless chaos, after its existence, was into a state of universal aqueous solution; for it was upon the surface of the waters that the Divine Spirit commenced his operative power. We are next informed that this chaotic mass acquired shape, not instantaneously, but by a series of six distinct days, or GENERATIONS (that is, epochs), as Moses afterwards calls them* ; and

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