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Show 88 UNIFORM.l'l'Y JN TllE thousand feet high, and has marked a long series both of vol-can l·c and submarine operations, all newer hth an. aln y of the 1·egular strata which enter larg:Iy into the p ystca str.ucture f Great Britain he returns With more exalted conceptiOns of ~1e antiquity of ;orne of those moder~ ~eposit.s, than he before entertained of the oldest of the llr1t1sh ser1es. We cannot reflect on the concessions thus extorted from us, in regard to the duration of past time, without foreseeing that the period may arrive when part of the H uttonian theory will be co~ bated o.n the ground of its departing too far from the ~ssumpt1~n of umformity in the order of nature. On a closer mvest1gat10n of ~xtinct volcanos, we find proofs that they broke out at succe~s1ve eras, and that the eruptions of one group were often concluded lon<Y before others had commenced their activity. Some were bu~ing when one class of organic beings were in ~xistence, others came into action when different races of ammals and plants existed,-it follows, therefore, that the convulsions caused by subterranean movements, which are merely another portion of the volcanic phenomena, occurred also in succe~sion, and their effects must be divided into separate sums, and assigned to separate periods of time; and this is not all :-when we examine the volcanic products, whether they be lavas which flowed out under water or upon dry land, we find that intervals of time, often of great length, intervened between their forination, and that the effects of one eruption were not greater in amount than that which now results during ordinary volcanic convulsions. The accompanying or preceding earthquakes, therefore, may be considered to have been also successive, and to have been in like manner inte~rupted by intervals of time, and not to have exceeded in violence those now experienced in the ordinary course of nature. Alreauy, therefore, may we regard the doctrine of the sudden elevation of whole continents by paroxysmal eruptions as invaliuated; and there was the greatest inconsistency in the adoption of such a tenet by the H uttonians, who were anxious to reconcile former changes to the present economy of the world. It was contrary to analogy to suppose, that Nature had been at any former epoch parsimonious of time and prodigal of violence-to imagine that one district was not at rest while another was convulsed-that the disturbing forces were not kept under subjection, so as never ORDER OF NATURE. 89 to carry simultaneous havoc and desolation over the whole earth, or even over one great region. If it could have been shown, that a certain combination of circumstances would at some future period produce a crisis in the subterranean action, we should certainly have had no right to oppose our experience for the last three thousand years as an argument against the probability of such occurrences in past ages; but it is not pretended that such a combination can be foreseen. In speculating on catastrophes by water, we may certainly anticipate great floods in future, and we may therefore presume that they have happened again and again in past times. '£he existence of enormous seas of fresh-water, such as the North American lakes, the largest of which is elevated more than six hundred feet above the level of the ocean, and is in parts twelve hundred feet deep, is alone sufficient to assure us, that the time will come, however distant, when a deluge will lay waste a considerable part of the American continent. No hypothetical agency is required to cause the sudden escape of the confined waters. Such changes of level, and opening of fissures, as have accompanied earthquakes since the commencement of the present century, or such excavation of ravines as the receding cataract of Niagara is now effecting, might breach the barriers. Notwithstanding, therefore, that we have not witnessed within the last three thousand years the devastation by deluge of a large continent, yet, as we may predict the future occu1-rence of such catastrophes, we are autl1orized to regard them as part of the present order of Nature, and they may be introduced into geological speculations respecting the past, provided we do not imagine them to have been more frequent or general than we expect them to be in time to come. The great contrast in the aspect of the older and newer rocks, in their texture, structure, and in the derangement of the strata, appeared formerly one of the strongest grounds for presuming that the causes to which they owed their origin were perfectly dissimilar from those now in operation. But this incongruity may now be regarded as the natural result ?f subsequent modifications, since the difference of relative age Is de~onstrated to have been so immense, that, however slow and insensible the change, it must have become important in the |