Modern Painters Volume IV Part 10

-- 11. It is another simple fact that this arrangement is not effected in an orderly and serene manner; but that the books, if they were ever neatly bound, have been fearfully torn to pieces and dog's-eared in the course of their elevation; sometimes torn leaf from leaf, but more commonly rent across, as if the paper had been wet and soft: or, to leave the book similitude, which is becoming inconvenient, the beds seem to have been in the consistence of a paste, more or less dry; in some places brittle, and breaking, like a cake, fairly across; in others moist and tough, and tearing like dough, or bending like hot iron; and, in others, crushed and shivering into dust, like unannealed gla.s.s. And in these various states they are either bent or broken, or shivered, as the case may be, into fragments of various shapes, which are usually tossed one on top of another, as above described; but, of course, under such circ.u.mstances, presenting, not the uniform edges of the books, but jagged edges, as in Fig. 9.

[Ill.u.s.tration: FIG. 10.]

-- 12. Do not let it be said that I am pa.s.sing my prescribed limits, and that I have tried to enter the clouds, and am describing operations which have never been witnessed. I describe facts or semblances, not operations. I say "_seem_ to have been," not "have been." I say "_are_ bent;" I do not say "_have been_ bent." Most travellers must remember the entrance to the valley of Cluse, from the plain of Bonneville, on the road from Geneva to Chamouni. They remember that immediately after entering it they find a great precipice on their left, not less than two thousand feet in perpendicular height. That precipice is formed by beds of limestone bent like a rainbow, as in Fig. 10. Their edges const.i.tute the cliff; the flat arch which they form with their backs is covered with pine forests and meadows, extending for three or four leagues in the direction of Sixt. Whether the whole mountain was called out of nothing into the form it possesses, or created first in the form of a level ma.s.s, and then actually bent and broken by external force, is quite irrelevant to our present purpose; but it is impossible to describe its form without appearing to imply the latter alternative; and all the distinct evidence which can be obtained upon the subject points to such a conclusion, although there are certain features in such mountains which, up to the present time, have rendered all positive conclusion impossible, not because they contradict the theories in question, but because they are utterly inexplicable on any theory whatever.

-- 13. We return then to our Fig. 9, representing beds which _appear_ to have been broken short off at the edges. "If they ever were actually broken," the reader asks, "what could have become of the bits?"

Sometimes they seem to have been lost, carried away no one knows where.

Sometimes they are really found in scattered fragments or dust in the neighborhood. Sometimes the mountain is simply broken in two, and the pieces correspond to each other, only leaving a valley between; but more frequently one half slips down, or the other is pushed up. In such cases, the coincidence of part with part is sometimes so exact, that half of a broken pebble has been found on one side, and the other half five or six hundred feet below, on the other.

-- 14. The beds, however, which are to form mountains of any eminence are seldom divided in this gentle way. If brittle, one would think they had been broken as a captain's biscuit breaks, leaving sharp and ragged edges; and if tough, they appear to have been torn asunder very much like a piece of new cheese.

The beds which present the most definite appearances of abrupt fracture, are those of that grey or black limestone above described (Chap. x. -- 4), formed into a number of thin layers or leaves, commonly separated by filmy spreadings of calcareous sand, hard when dry, but easily softened by moisture; the whole, considered as a ma.s.s, easily friable, though particular beds may be very thick and hard. Imagine a layer of such substance, three or four thousand feet thick, broken with a sharp crash through the middle, and one piece of it thrown up as in Fig. 11. It is evident that the first result of such a shock would be a complete shattering of the consistence of the broken edges, and that these would fall, some on the instant, and others tottering and crumbling away from time to time, until the cliff had got in some degree settled into a tenable form. The fallen fragments would lie in a confused heap at the bottom, hiding perhaps one half of its height, as in Fig. 12; the top of it, wrought into somewhat less ragged shape, would thenceforth submit itself only to the gradual influences of time and storm.

[Ill.u.s.tration: FIG. 11.]

[Ill.u.s.tration: FIG. 12.]

I do not say that this operation has actually taken place. I merely say that such cliffs do in mult.i.tudes _exist_ in the form shown at Fig. 12, or, more properly speaking, in that form modified by agencies in visible operation, whose work can be traced upon them, touch by touch.

But the condition at Fig. 12 is the first rough blocking out of their form, the primal state in which they demonstrably were, some thousands of years ago, but beyond which no human reason can trace them without danger of error. The cloud fastens upon them there.

-- 15. It is rare, however, that such a cliff as that represented in Fig.

12 can maintain itself long in such a contour. Usually it moulders gradually away into a steep mound or bank; and the larger number of bold cliffs are composed of far more solid rock, which in its general make is quite unshattered and flawless; apparently unaffected, as far as its coherence is concerned, by any shock it may have suffered in being raised to its position, or hewn into its form. Beds occur in the Alps composed of solid coherent limestone (such as that familiar to the English traveller in the cliffs of Matlock and Bristol), 3000 or 4000 feet thick, and broken short off throughout a great part of this thickness, forming nearly[50] sheer precipices not less than 1500 or 2000 feet in height, after all deduction has been made for slopes of debris at the bottom, and for rounded diminution at the top.

-- 16. The geologist plunges into vague suppositions and fantastic theories in order to account for these cliffs; but, after all that can be dreamed or discovered, they remain in great part inexplicable. If they were interiorly shattered, it would be easy to understand that, in their hardened condition, they had been broken violently asunder; but it is not easy to conceive a firm cliff of limestone broken through a thickness of 2000 feet without showing a crack in any other part of it.

If they were divided in a soft state, like that of paste, it is still less easy to understand how any such soft material could maintain itself, till it dried, in the form of a cliff so enormous and so ponderous: it must have flowed down from the top, or squeezed itself out in bulging protuberance at the base. But it has done neither; and we are left to choose between the suppositions that the mountain was created in a form approximating to that which it now wears, or that the shock which produced it was so violent and irresistible, as to do its work neatly in an instant, and cause no flaws to the rock except in the actual line of fracture. The force must have been a.n.a.logous either to the light and sharp blow of the hammer with which one breaks a stone into two pieces as it lies in the hand, or the parting caused by settlement under great weight, like the cracks through the brickwork of a modern ill-built house. And yet the very beds which seem at the time they were broken to have possessed this firmness of consistency, are also bent throughout their whole body into waves, apparently following the action of the force that fractured them, like waves of sea under the wind. Truly the cloud lies darkly upon us here!

[Ill.u.s.tration: FIG. 13.]

-- 17. And it renders these precipices more remarkable that there is in them no principle of compensation against destructive influences. They are not cloven back continually into new cliffs, as our chalk sh.o.r.es are by the sea; otherwise, one might attribute their first existence to the force of streams. But, on the contrary, the action of years upon them is now always one of deterioration. The increasing heap of fallen fragments conceals more and more of their base, and the wearing of the rain lowers the height and softens the sternness of their brows, so that a great part of their terror has evidently been subdued by time; and the farther we endeavor to penetrate their history, the more mysterious are the forms we are required to explain.

The three great representative forms of stratified mountains.

-- 18. Hitherto, however, for the sake of clearness, we have spoken of hills as if they were composed of a single ma.s.s or volume of rock. It is very seldom that they are so. Two or three layers are usually raised at once, with certain general results on mountain form, which it is next necessary to examine.

1. Wall above slope.

1st. Suppose a series of beds raised in the condition _a_, Fig. 13, the lowest soft, the uppermost compact; it is evident that the lower beds would rapidly crumble away, and the compact ma.s.s above break for want of support, until the rocks beneath had reached a slope at which they could securely sustain themselves, as well as the weight of wall above, thus bringing the hill into the outline _b_.

[Ill.u.s.tration: FIG. 14.]

2. Slope above wall.

2d. If, on the other hand, the hill were originally raised as at _c_, the softest beds being at the top, these would crumble into their smooth slope without affecting the outline of the ma.s.s below, and the hill would a.s.sume the form _d_, large ma.s.ses of debris being in either of these two cases acc.u.mulated at the foot of the slope, or of the cliff.

These first ruins might, by subsequent changes, be variously engulfed, carried away, or covered over, so as to leave nothing visible, or at least nothing notable, but the great cliff with its slope above or below it. Without insisting on the evidences or probabilities of such construction, it is sufficient to state that mountains of the two types, _b_ and _d_, are exceedingly common in all parts of the world; and though of course confused with others, and themselves always more or less imperfectly developed, yet they are, on the whole, singularly definite as cla.s.ses of hills, examples of which can hardly but remain clearly impressed on the mind of every traveller. Of the first, _b_, Salisbury Crags, near Edinburgh, is a nearly perfect instance, though on a diminutive scale. The cliffs of Lauterbrunnen, in the Oberland, are almost without exception formed on the type _d_.

3. Slope and wall alternately.

3d. When the elevated ma.s.s, instead of consisting merely of two great divisions, includes alternately hard and soft beds, as at _a_, Fig. 14, the vertical cliffs and inclined banks alternate with each other, and the mountain rises on a series of steps, with receding slopes of turf or debris on the ledge of each, as at _b_. At the head of the valley of Sixt, in Savoy, huge ma.s.ses of mountain connected with the Buet are thus constructed: their slopes are quite smooth, and composed of good pasture land, and the cliffs in many places literally vertical. In the summer the peasants make hay on the inclined pastures; and the hay is "carried"

by merely binding the hayc.o.c.ks tight and rolling them down the slope and over the cliff, when I have heard them fall to the bank below, a height of from five to eight hundred feet, with a sound like the distant report of a heavy piece of artillery.

[Ill.u.s.tration: FIG. 15.]

-- 19. The next point of importance in these beds is the curvature, to which, as well as to fracture, they seem to have been subjected. This curvature is not to be confounded with that rippling or undulating character of every portion of the slaty crystalline rocks above described. I am now speaking of all kinds of rocks indifferently;--not of their appearance in small pieces, but of their great contours in ma.s.ses, thousands of feet thick. And it is almost universally true of these ma.s.ses that they do not merely lie in flat superposition one over another, as the books in Fig. 8; but they lie in _waves_, more or less vast and sweeping according to the scale of the country, as in Fig. 15, where the distance from one side of the figure to the other is supposed to be four or five leagues.

-- 20. Now, observe, if the precipices which we have just been describing had been broken when their substance was in a hard state, there appears no reason why any connexion should be apparent between the energy of _undulation_ and these _broken_ rocks. If the continuous waves were caused by convulsive movements of the earth's surface while its substance was pliable, and were left in repose for so long a period as to become perfectly hard before they were broken into cliffs, there seems no reason why the second series of shocks should so closely have confined itself to the locality which had suffered the first, that the most abrupt precipices should always be a.s.sociated with the wildest waves. We might have expected that sometimes we should have had n.o.ble cliffs raised where the waves had been slight; and sometimes low and slight fractures where the waves had been violent. But this is not so.

The contortions and fractures bear always such relation to each other as appears positively to imply contemporaneous formation. Through all the lowland districts of the world the average contour of the waves of rock is somewhat as represented in Fig. 16 _a_, and the little cliffs or hills formed at the edges of the beds (whether by fracture, or, as oftener happens in such countries, by gradual washing away under the surge of ancient seas) are no higher, in proportion to the extent of surface, than the little steps seen in the centre of the figure. Such is the nature, and such the scale, of the ranges of hills which form our own downs and wolds, and the French coteaux beside their winding rivers.

But as we approach the hill countries, the undulation becomes more marked, and the crags more bold; so that almost any portion of such mountain ranges as the Jura or the Vosges will present itself under conditions such as those at _b_, the precipices at the edges being bolder in exact proportion to the violence of wave. And, finally, in the central and n.o.blest chains the undulation becomes literally contortion; the beds occur in such positions as those at _c_, and the precipices are bold and terrific in exact proportion to this exaggerated and tremendous contortion.

[Ill.u.s.tration: FIG. 16.]

-- 21. These facts appear to be just as contrary to the supposition of the mountains having been formed while the rocks were hard, as the considerations adduced in -- 15 are to that of their being formed while they were soft. And I believe the more the reader revolves the subject in his thoughts, and the more opportunities he has of examining the existing facts, the less explicable those facts will become to him, and the more reverent will be his acknowledgment of the presence of the cloud.

For, as he examines more clearly the structure of the great mountain ranges, he will find that though invariably the boldest forms are a.s.sociated with the most violent contortions, they sometimes _follow_ the contortions, and sometimes appear entirely independent of them. For instance, in crossing the pa.s.s of the Tete Noire, if the traveller defers his journey till near the afternoon, so that from the top of the pa.s.s he may see the great limestone mountain in the Valais, called the Dent de Morcles, under the full evening light, he will observe that its peaks are hewn out of a group of contorted beds, as shown in Fig. 4, Plate 29. The wild and irregular zigzag of the beds, which traverse the face of the cliff with the irregularity of a flash of lightning, has apparently not the slightest influence on the outline of the peak. It has been carved out of the ma.s.s, with no reference whatever to the interior structure. In like manner, as we shall see hereafter, the most wonderful peak in the whole range of the Alps seems to have been cut out of a series of nearly horizontal beds, as a square pillar of hay is cut out of a half-consumed haystack. And yet, on the other hand, we meet perpetually with instances in which the curves of the beds have in great part directed the shape of the whole ma.s.s of mountain. The gorge which leads from the village of Ardon, in the Valais, up to the root of the Diablerets, runs between two ranges of limestone hills, of which the rude contour is given in Fig. 17, page 154. The great slope seen on the left, rising about seven thousand feet above the ravine, is nothing but the back of one sheet of limestone, whose broken edge forms the first cliff at the top, a height of about six hundred feet, the second cliff being the edge of another bed emergent beneath it, and the slope beyond, the surface of a third. These beds of limestone all descend at a uniform inclination into the gorge, where they are snapped short off, the torrent cutting its way along the cleft, while the beds rise on the other side in a huge contorted wave, forming the ridge of mountains on the right,--a chain about seven miles in length, and from five thousand to six thousand feet in height. The actual order of the beds is seen in Fig. 18, and it is one of the boldest and clearest examples of the form of mountains being correspondent to the curves of beds which I have ever seen; it also exhibits a condition of the summits which is of constant occurrence in stratified hills, and peculiarly important as giving rise to the serrated structure, rendered cla.s.sical by the Spaniards in their universal term for mountain ridges, Sierra, and obtaining for one of the most important members of the Comasque chain of Alps its well known Italian name--Il Resegone. Such mountains are not merely successions of irregular peaks, more or less resembling the edge of a much-hacked sword; they are orderly successions of teeth set in one direction, closely resembling those of a somewhat overworn saw, and nearly always produced by successive beds emerging one from beneath the other.

[Ill.u.s.tration: FIG. 18.]

[Ill.u.s.tration: FIG. 17.]

-- 22. In all such cases there is an infinitely greater difficulty in accounting for the forms than in explaining the fracture of a single bed. How, and when, and where, were the other portions carried away? Was each bed once continuous over a much larger s.p.a.ce from the point where its edge is now broken off, or have such beds slipped back into some gulf behind them? It is very easy for geologists to speak generally of elevation and convulsion, but very difficult to explain what sort of convulsion it could be which pa.s.sed forward from the edge of one bed to the edge of another, and broke the required portion off each without disturbing the rest. Try the experiment in the simplest way: put half a dozen of hard captain's biscuits in a sloping position on a table, and then try, as they lie, to break the edge of each, one by one, without disturbing the rest. At least, you will have to raise the edge before you can break it; to put your hand underneath, between it and the next biscuit, before you can get any purchase on it. What force was it that put its fingers between one bed of limestone 600 feet thick and the next beneath? If you try to break the biscuits by a blow from above, observe the necessary force of your blow, and then conceive, if you can, the sort of hammer that was required to break the 600 feet of rock through in the same way. But, also, you will, ten to one, break two biscuits at the same time. Now, in these serrated formations, two biscuits are _never_ broken at the same time. There is no appearance of the slightest jar having taken place affecting the bed beneath. If there be, a huge cliff or gorge is formed at that spot, not a sierra. Thus, in Fig. 18, the beds are affected throughout their united body by the shock which formed the ravine at _a_; but they are broken, one by one, into the cliffs at _b_ and _c_. Sometimes one is tempted to think that they must have been slipped back, one from off the other; but there is never any appearance of friction having taken place on their exposed surfaces; in the plurality of instances their continuance or rise from their roots in waves (see Fig. 16 above) renders the thing utterly impossible; and in the few instances which have been known of such action actually taking place (which have always been on a small scale), the sliding bed has been torn into a thousand fragments almost as soon as it began to move.[51]

-- 23. And, finally, supposing a force found capable of breaking these beds in the manner required, what force was it that carried the fragments away? How were the gigantic fields of shattered marble conveyed from the ledges which were to remain exposed? No signs of violence are found on these ledges; what marks there are, the rain and natural decay have softly traced through a long series of years. Those very time-marks may have indeed effaced mere superficial appearances of convulsion; but could they have effaced all evidence of the action of such floods as would have been necessary to carry bodily away the whole ruin of a block of marble leagues in length and breadth, and a quarter of a mile thick? Ponder over the intense marvellousness of this. The bed at _c_ (Fig. 18) must first be broken through the midst of it into a sharp precipice, without at all disturbing it elsewhere; and then all of it beyond _c_ is to be broken up, and carried perfectly away, without disturbing or wearing down the face of the cliff at _c_.

And yet no trace of the means by which all this was effected is left.

The rock stands forth in its white and rugged mystery, as if its peak had been born out of the blue sky. The strength that raised it, and the sea that wrought upon it, have pa.s.sed away, and left no sign; and we have no words wherein to describe their departure, no thoughts to form about their action, than those of the perpetual and unsatisfied interrogation,--

"What ailed thee, O thou sea, that thou fleddest?

And ye mountains, that ye skipped like lambs?"

FOOTNOTES

[49] How far, is another question. The sand which the stream brings from the bottom of one eddy in its course, it throws down in the next; all that is _proved_ by the above trial is, that so many tons of material are annually carried down by it a certain number of feet.

[50] _Nearly_; that is to say, not quite vertical. Of the degree of steepness, we shall have more to say hereafter.

[51] The Rossberg fall, compared to the convulsions which seem to have taken place in the higher Alps, is like the slip of a paving stone compared to the fall of a tower.

CHAPTER XIII.

OF THE SCULPTURE OF MOUNTAINS:--SECONDLY, THE CENTRAL PEAKS.