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the limestone, the greenstone, and indeed all the compounds of hornblende and felspar, in this order of rocks, differ from the primitive in no other circumstance than in not being quite so much crystallized, and in exhibiting a few organic fossils. Indeed, we should not be surprised to find a successive gradation from the oldest granite down to the newest floetz trap; and if it should be said in consequence of this that the nomenclature of the science ought to be changed, it would be conceded perhaps that better words might possibly be found out.

But really all this does not affect the ground-work of the Wernerian theory, and in fact goes very little further to invali. date its leading doctrines than irregular verbs in grammar, or comets in the planetary system would go to prove that the grammarian and the astronomer are guided by no general rules. Professor Kidd holds the distinguishing tenet of the aqueous solution and consequent precipitation of the materials which form the crust of the earth; and when he maintains that the evidence in support of Werner's theory is imperfect, be alludes solely to his classification of the various rocky substances, and perhaps to the hypothetical assumption which is involved in the term transition. This we regard rather as an expression of the Professor's opinion that geognostic science is still in its infancy, than that the principles are erroneous upon which the disciples of Werner reason, and prosecute their researches. At least we will make bold to assert that his Geological Essay contains nothing inconsistent with the doctrines of that distinguished phi. Josopher, and that he has only stated a few facts which deserve attention in order to be explained, rather than exposed any glar. ing discrepancy between those doctrines and the general appear. ances of the earth's surface.

Among the most important of the notices which are collected in this essay, we are inclined to enumerate those which respect the arrangement of mouutain groups. In the third volume of Professor Jameson's work on mineralogy we are taught to believe tbat there is a certain order and regularity in the collocation of mountains ; that where a group is viewed as a whole, it appears highest in the middle, and that this highest part extends through the whole group without being intersected. The lateral cbains, it is added, shoot on both sides from the high mountain chain, and of these the most considerable is that which rises from the high mountain chain itself, and reaches to the foot of the group*. There are also two chief kinds of vallies analogous to the mountains, called the principal, and lateral or subordi

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+ See Jameson, vol. ii. p. 11, &c.

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nate. The principal vallies stretch without interruption from the high mountain chain to the foot of the mountain group, and those only are principal vallies that reach this point: the others, which merely extend from a mountain chain to a principal valley are subordinate *. We were not without suspicion that Werner and his pupils had reduced the mountains and vallies to greater order in their system than they are to be found in nature, and our suspicion is confirmed by the following remarks.

“ To begin with the Alps, which are not only the most remarkable assemblage of mountains in Europe, but have been ex. amined and described more accurately than any other, it does not appear either from the maps of Weiss, or from the observations of Saussure, that there is any thing like that regularity of parallelism in the vallies of those mountains, which one is led to expect from the general theory of Werner, nor any thing like that regularity in the succession of the strata pointed out by the same theory. So far from it, that after the lapse of many years spent in a most laborious examination of them, with every assistance and every qualification necessary for the purpose, Saussure came to this conclusion ; that there is nothing constant either in the order, character, direction, or degree of inclination, of the strata composing that majestic assemblage of mountains : nothing, in short, constant in them but their variety t. On another occasion also he confesses that in viewing the group placed beneath his eyes from one of the highest summits near St. Gothard, the direction of the vallies did not appear to have any constant correspondence with the bearings of the strata ; being sometimes placed parallel with, and sometimes at an oblique or even a right angle to them I. Again, he observes of the primitive mountains of Italy, Switzer. land, and Savoy, that though at a great distance they appear to have that regular arrangement which has given rise to the term chain ; yet this is a false impression, which vanishes upon a closer inspection : and in another volume he asserts, that the chains of the Apennines near Genoa have no regularity either in their own direction, or in the direction of their accompanying vallies 11. The immediate group of Mont Blanc, the Aiguilles of Chamouni, and the group which is to the south-west of Mont Blanc, are not at all connected with each other and Mont Blanc itself, though the highest summit of the Alps, is not in the centre of the mass of primitive mountains which surround it: for on the side of Italy there are many more high summits than on the side of Savoy; so

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p. 241.'

« * See Jameson, vol. iii. p 14."
“Saussure, tom. vii. p. 51."

Ibid. tom. V. 249."

46 + Saussure, tom. viii.
g Ibid. tom. vii. p. 290.”

9. Ibid. tom. vii. p. 292.”

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that Mont Blane is nearly on an extreme border of this mass of primitive mountains *.

“ Mont Rosa, which is situated at the upper extremity of the Vallais, and appears to have been so named from the circular arrangement of its numerous peaks, disposed somewhat in the mander of the leaves of

rose, has an arrangement unlike all the elevated summits Saussure had ever seen: for such elevatee summits usually are insulated like Etna, or ranged in right lines as Mont Blanc and its collateral peaks. Mont Rosa, on the contrary, composed of an uninterrupted suit of nearly equal peaks, forms a vast circus, which incloses within its area several hamlets, numerous pastures, and glaciers bordering on those pastures, and steep acclivities, which are continued to the very summits of these stupendous peaks t. The foregoing description corresponds partially with the description of the valley of Mexico. This valley, which is about 18 leagues in length and 12 in breadth, is situated on the summit of porphyritic and amygdaloid basaltic rocks, surrounded by a circular crest of mountains 67 leagues in circumference f.

“ In comparing the Alps on the Italian or Piedmontese side with those on the side of Savoy, Switzerland, and Dauphiny, there are great differences observable both with respect to the height and nature of the mountains. On the side of Piedmont they terminate more abruptly; forming a wall, as it were, and rising sudđenly from the termination of the plain of Piedmort g. 'Nor does this

appear to be, entirely at least, the effect of an aetual removal of a part of the group; since even in the case of Mont Blanc, which is fanked by e terior chains on the side of Italy, and protected therefore from the action of any removing cause in that direction, the escarpments are much more abrupt on that side than in

any other direction 11.

" The nature of the strata is often as capricious as their arrangement: thus the most elevated and central parts of the chain of Mont Cenis are calcareo-micaceous schists; while granite fornis the secondary ridges: and the central and highest rocks are nearly horizontal in their stratification, while the exterior ridges are nearly vertical . On the south-east side of the Alps the granite descends nearly into the plain, and there are scarcely any calcareous strata till you approach Genoa or Venice; and there is serpentine in abundance : but the converse of this holds on the worth-west side: and Saussure adds, that Pallas has also noticed in Russia and Siberia a marked difference between opposite sides of the same chain **.

The opposite sides of the chain which the passage of the Simplon traverses are very different: the northern

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4 * Saussure, tom. vii. p. 300.”
" # Humboldt; tom. ii. p. 106."*.

# Saussure, tony. V. p. 173."
* ** Ibid. tom. iv. p. 215, 216."

66 + Ibid. tom. viii.

P. 54." 68. Ibid. tom. v.

Ibid. tom. v. p. 174."

p. 170.»

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"side, looking to the Vallais, consists almost entirely of vertical beds of micaceous limestone: the southern side, looking to Italy, consists of quartzose inicaceous schist, of gneiss, and of a schistose granite, in strata either horizontal or inclined at an angle not greater than from thirty to forty *.” P. 138.

We are not aware that the principles, upon which the Wernerians explain the formation of the primitive mountains, would lead us, a priori, to expect the regularity and subordination which are supposed to appear in their arrangement. At all events, if we take into consideration the tremendous disruptions, uplifting, and overturnings to which the whole outer crust of the earth has been subjected, we shall no longer be surprised at the want of uniformity in the collocation of niountain masses. A more extensive and careful examination of

particulars will, we have no doubt, bring many things to light calculated to arrest the premature generalization to which we are now alluding; and surely when we advert to the almost boundless field in which observation must be carried on ;-the most elevated mountains and the deepest ravines, the excava. tions of the miner, and the natural cavern, the shores of Lapland, of New Holland and of China, the burning continent and the frozen island, -it will not be thought astonishing should new discoveries occasionally demand a little modification of theory. But we repeat once more, that the fundamental doctrines of Werner are not involved in any of the apparent ano. malies which Professor Kidd has brought forward.

In enumerating the agents which appear to have been employed in the production of geological phenomena, it may seem strange to pass without noticing the Mosaical deluge. It may be replied, in excuse of the omission, that the waters which were brought upon the earth to punish the sins of men are not only comparatively recent, but, except some beds of gravel and rolled "masses of rocks, there are no appearances which can be certainly ascribed to their operation. The great works of nature were already past, the chaotic waters had long ago deposited the materials which they held suspended in solution; the mountains were consolidated, and the stratified rocks had assumed their places at their respective levels, long before the iniquity of inen waxed great on the earth. The flood, therefore, has left no traces of its presence but in the devastation it produced ; and setting aside all authority but that of science, the most determined sceptic must admit, that a

powerful rush of waters has passed over many parts of the earth's sura

* Saussure, tom. viii. pa 29."

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face, since it was first faid dry. The most unequivocal proof of this, in our opinion, are those huge insulated inasses of stone which are found in every part of the globe; for, as Dr. Kidd observes, they are evidently water-worn, and, judging from the identity of their internal character, have as evidently, once formed a portion of some of the native strata.

* It was Saussure's opinion that the waters of the ocean, in which he supposes mountains to have been formed, were still in part covering those mountains, when a violent earthquake all at once opened numerous subterranean cavities, and rent asunder many of the strata. The waters then rushing towards those cavities, with a violence proportioned to the height of their level, excavated deep vallies, and carried with them immense quantities of earth, sand, and fragments of all kinds of rocks. This half liquid aceumulation, hurried on by the weight of the water, lodged itself at those heights where we still see many of the scattered fragments. The waters afterwards continuing to run, but with a rapidity gra.. dually lessening in proportion to the diminution of their height, carried away by little and little the lightest particles; and cleared the vallies of the heaps of mud by which they had been clogged, leaving behind either the heavier masses only, or those also, which accidental position or an unusually settled lodgment protected from their action *.

" A rush of water, like that just described, Saussure calls a débacle; and the sudden eruption of a mass of water from any barrier which had previously confined it, would represent the effects of a debacle on a small scale. The great debacle, to which in his writings he so often alludes, is supposed to have been occasioned by the sudden retreat of the waters of the chaotic.ocean, as above described : and he thinks it probable, that the beds of the principal Alpine vallies have in many instances been formed by sand and gravel brought by the great debacle + : and that rivers, (as in the. valley of the Durance which rises in high Darphiny,) by washing away the earth and sand mixed with the pebbles that have been formerly deposited, bring these pebbles to view 1." P. 168.

This debacle of the French philosopher would correspond sufficiently in its effects with the Mosaic deluge, provided there were found in the immense gravel depositions which every where occur, any fossil, remains of the human species. It seens unanimously agreed among antiquaries and anatomists that, except the specimen lately sent from Guadaloupe by Sir Alesander Cochrane, no human skeleton has ever been found, even in alluvial formation. Various accouuts indeed have been

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«Ibid. tom. ii.

p.

208."

A well

Saussure, tom. i. p. 205." 1 Ibid. tom. vi. p: 77."

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