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it leaves an undecided interval between the two, nay more, informs us that there was a state of confusion and conflict, of waste and darkness, and a want of a proper basin for the sea, which thus would cover first one part of the earth, and then another; we may truly say, that the geologist reads in those few lines the history of the earth, such as his monuments have recorded it,—a series of disruptions, elevations, and dislocations; sudden inroads of the unchained element, entombing successive generations of amphibious animals; calm, but unexpected subsidences of the waters, embalming in their various beds their myriads of aquatic inhabitants ;* alternations of sea and land, and fresh-water lakes; an atmosphere obscured by dense carbonic vapour, which, by gradual absorption in the waters, was cleared away, and produced the pervading mass of calcareous formations; till at length came the last revolution preparatory for our creation, when the earth, being now sufficiently broken for that beautiful diversity which God intended to bestow on it, or to produce those landmarks and barriers which his foreseeing counsels had designed, the work of ruin was suspended, save for one more great Scourge ;-and the earth remained in that state of sullen and gloomy prostration, from which it

* See this point beautifully treated by De la Beche, "Researches into Theoretical Geology," London, 1834, chap. xii. p. 242.

was recalled by the reproduction of light, and the subsequent work of the six days' creation.

But I think we may well say, that even on this first point of our geological investigation, science has gone farther than I have stated. For I think we are in a fair way to discover so beautiful a simplicity of action in the causes which have produced the present form of the earth, and, at the same time, such a manifest approach to the progressive method manifested in the known order of God's works, as to confirm, if such a term may be used, all that he hath manifested in his own sacred word.

For when I have spoken of successive revolutions, destructions, and reproductions, I have meant not a mere series of unconnected changes, but the steady action of a single cause, producing most complete variations, according to established laws. And this, I may say, it is certainly the tendency of modern geology to establish. I have before slightly touched on the subject of central heat, or the existence of a principle of that power, in the interior of the earth; whether it arise from the former state of the globe, or from some other source, it matters not. it matters not. That its action can be even now sufficiently violent to effect revolutions on our earth,-great, if viewed in reference to particular tracts,—in miniature, if compared to its primeval efforts,-must be known, from observation, to most of you, who have visited the

scenes of volcanic action. There, islands have been formed, and swallowed up again, hills have been raised, the cones of mountains broken down, the sea has altered its boundaries, and fruitful fields have been changed into black tracts of desolation. Suppose this power acting on a gigantic scale, not in one district, but over the entire world, now bursting out on one side, and now on the other; the effects must have been convulsive to a frightful degree, the disruptions must have been far more tremendous, and mountains may have been heaved up instead of hills, like Monte Rosso, which Ætna raised in 1669, or the sea may have invaded large territories, instead of small tracts of coast.

The observations of geologists go far towards proving the action of some such power, in the manner which I have described: Leopold von Buch, first proved that mountains, instead of being the most immoveable and firm portions of the earth's structure, and existing previously to the softer materials which repose on their sides, have, on the contrary, been raised up through these, by an upheaving action from below. M. Elie de Beaumont has carried this observation so much farther, as almost to be considered the founder of the theory. One simple demonstration of it you will easily comprehend. If the various strata on the side of a mountain, though necessarily precipitations of a solution in water, instead of lying horizontally,

as such precipitations must do, and consequently cutting the mountain's sides at angles, thus, (a being the section of the mountain, and b representing the surrounding strata,)

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shall, on the contrary, lie parallel to its sides in this

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it is manifest that the mountain must have been thrust up through the strata already deposited. M. de Beaumont, by comparing the various strata thus perforated, as it were, by each chain of mountains, with those which lie in horizontal order, as if deposited after its elevation, endeavours to determine the period, in the series of primeval revolutions, when each was upraised. And each of these systems of mountains, as he calls them, produced, or accompanied some great catastrophe, destructive, to a certain extent, of the existing order of things. This system of the French geo

* "Revue Française," May, 1830, p. 55. See also his MS.

logists has been confirmed and adopted by the scientific men of our own country. Professor Sedgwick and Mr. Murchison remark upon the phenomena observable in the isle of Arran, that they seem to prove the great dislocations of the secondary strata, to have been " produced by the elevation of the granite" in which case, “the upheaving forces must have been in action some time after the deposition and consolidation of the new red sandstone."* But De la Beche is clearly of opinion that these successive elevations, indicative of the convulsions which disturbed the quiet action of sedimentary depositions, may be farther simplified, by reference to one cause, that is the power of a great central heat, variously breaking the earth's crust, whether by the progress of refrigeration, as he supposes, or as the author of the theory imagines, by volcanic action.

Now it seems to me that this theory, by its beautiful unity in cause and action, is in perfect accordance with all we know of the methods used by divine Providence, which establishes a law and then leaves it to act; so that the budding forth of

communications to De la Beche, in his Manual, pp. 481, seqq. Carlo Gemmellaro informs us, that at the scientific meeting at Stuttgard, in 1834, he read a paper proposing a modification of the Theory, and restricting the elevation of mountain chains to small spaces. "Relazione sul di lui viaggio a Stuttgard." Cata

nia, 1835, p. 12.

* Geolog. Trans. vol. iii. p. 34.

Researches, p. 39.

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