CHAPTER XII.
ON THE SCULPTURE OF MOUNTAINS:—FIRST, THE LATERAL RANGES.
§ 1. Close beside the path by which travellers ascend the Montanvert from the valley of Chamouni, on the right hand, where it first begins to rise among the pines, there descends a small stream from the foot of the granite peak known to the guides as the Aiguille Charmoz. It is concealed from the traveller by a thicket of alder, and its murmur is hardly heard, for it is one of the weakest streams of the valley. But it is a constant stream; fed by a permanent though small glacier, and continuing to flow even to the close of the summer, when more copious torrents, depending only on the melting of the lower snows, have left their beds "stony channels in the sun."
I suppose that my readers must be generally aware that glaciers are masses of ice in slow motion, at the rate of from ten to twenty inches a day, and that the stones which are caught between them and the rocks over which they pass, or which are embedded in the ice and dragged along by it over those rocks, are of course subjected to a crushing and grinding power altogether unparalleled by any other force in constant action. The dust to which these stones are reduced by the friction is carried down by the streams which flow from the melting glacier, so that the water which in the morning may be pure, owing what little strength it has chiefly to the rock springs, is in the afternoon not only increased in volume, but whitened with dissolved dust of granite, in proportion to the heat of the preceding hours of the day, and to the power and size of the glacier which feeds it.
§ 2. The long drought which took place in the autumn of the year 1854, sealing every source of waters except these perpetual ones, left the torrent of which I am speaking, and such others, in a state peculiarly favorable to observance of their least action on the mountains from which they descend. They were entirely limited to their own ice fountains, and the quantity of powdered rock which they brought down was, of course, at its minimum, being nearly unmingled with any earth derived from the dissolution of softer soil, or vegetable mould, by rains.
At three in the afternoon, on a warm day in September, when the torrent had reached its average maximum strength for the day, I filled an ordinary Bordeaux wine-flask with the water where it was least turbid. From this quart of water I obtained twenty-four grains of sand and sediment, more or less fine. I cannot estimate the quantity of water in the stream; but the runlet of it at which I filled the flask was giving about two hundred bottles a minute, or rather more, carrying down therefore about three quarters of a pound of powdered granite every minute. This would be forty-five pounds an hour; but allowing for the inferior power of the stream in the cooler periods of the day, and taking into consideration, on the other side, its increased power in rain, we may, I think, estimate its average hour's work at twenty-eight or thirty pounds, or a hundred weight every four hours. By this insignificant runlet, therefore, some four inches wide and four inches deep, rather more than two tons of the substance of the Mont Blanc are displaced, and carried down a certain distance every week; and as it is only for three or four months that the flow of the stream is checked by frost, we may certainly allow eighty tons for the mass which it annually moves.
§ 3. It is not worth while to enter into any calculation of the relation borne by this runlet to the great torrents which descend from the chain of Mont Blanc into the valley of Chamouni. To call it the thousandth part of the glacier waters, would give a ludicrous under-estimate of their total power; but even so calling it, we should find for result that eighty thousand tons of mountain must be yearly transformed into drifted sand, and carried down a certain distance.[49] How much greater than this is the actual quantity so transformed I cannot tell; but take this quantity as certain, and consider that this represents merely the results of the labor of the constant summer streams, utterly irrespective of all sudden falls of stones and of masses of mountain (a single thunderbolt will sometimes leave a scar on the flank of a soft rock, looking like a trench for a railroad); and we shall then begin to apprehend something of the operation of the great laws of change, which are the conditions of all material existence, however apparently enduring. The hills, which, as compared with living beings, seem "everlasting," are, in truth, as perishing as they: its veins of flowing fountain weary the mountain heart, as the crimson pulse does ours; the natural force of the iron crag is abated in its appointed time, like the strength of the sinews in a human old age; and it is but the lapse of the longer years of decay which, in the sight of its Creator, distinguishes the mountain range from the moth and the worm.
§ 4. And hence two questions arise of the deepest interest. From what first created forms were the mountains brought into their present condition? into what forms will they change in the course of ages? Was the world anciently in a more or less perfect state than it is now? was it less or more fitted for the habitation of the human race? and are the changes which it is now undergoing favorable to that race or not? The present conformation of the earth appears dictated, as has been shown in the preceding chapters, by supreme wisdom and kindness. And yet its former state must have been different from what it is now; as its present one from that which it must assume hereafter. Is this, therefore, the earth's prime into which we are born; or is it, with all its beauty, only the wreck of Paradise?
I cannot entangle the reader in the intricacy of the inquiries necessary for anything like a satisfactory solution of these questions. But, were he to engage in such inquiries, their result would be his strong conviction of the earth's having been brought from a state in which it was utterly uninhabitable into one fitted for man;—of its having been, when first inhabitable, more beautiful than it is now; and of its gradually tending to still greater inferiority of aspect, and unfitness for abode.
It has, indeed, been the endeavor of some geologists to prove that destruction and renovation are continually proceeding simultaneously in mountains as well as in organic creatures; that while existing eminences are being slowly lowered, others, in order to supply their place, are being slowly elevated; and that what is lost in beauty or healthiness in one spot is gained in another. But I cannot assent to such a conclusion. Evidence altogether incontrovertible points to a state of the earth in which it could be tenanted only by lower animals, fitted for the circumstances under which they lived by peculiar organizations. From this state it is admitted gradually to have been brought into that in which we now see it; and the circumstances of the existing dispensation, whatever may be the date of its endurance, seem to me to point not less clearly to an end than to an origin; to a creation, when "the earth was without form and void," and to a close, when it must either be renovated or destroyed.
§ 5. In one sense, and in one only, the idea of a continuous order of things is admissible, in so far as the phenomena which introduced, and those which are to terminate, the existing dispensation, may have been, and may in future be, nothing more than a gigantic development of agencies which are in continual operation around us. The experience we possess of volcanic agency is not yet large enough to enable us to set limits to its force; and as we see the rarity of subterraneous action generally proportioned to its violence, there may be appointed, in the natural order of things, convulsions to take place after certain epochs, on a scale which the human race has not yet lived long enough to witness. The soft silver cloud which writhes innocently on the crest of Vesuvius, rests there without intermission; but the fury which lays cities in sepulchres of lava bursts forth only after intervals of centuries; and the still fiercer indignation of the greater volcanoes, which make half the globe vibrate with earthquake, and shrivels up whole kingdoms with flame, is recorded only in dim distances of history: so that it is not irrational to admit that there may yet be powers dormant, not destroyed, beneath the apparently calm surface of the earth, whose date of rest is the endurance of the human race, and whose date of action must be that of its doom. But whether such colossal agencies are indeed in the existing order of things or not, still the effective truth, for us, is one and the same. The earth, as a tormented and trembling ball, may have rolled in space for myriads of ages before humanity was formed from its dust; and as a devastated ruin it may continue to roll, when all that dust shall again have been mingled with ashes that never were warmed by life, or polluted by sin. But for us the intelligible and substantial fact is that the earth has been brought, by forces we know not of, into a form fitted for our habitation: on that form a gradual, but destructive, change is continually taking place, and the course of that change points clearly to a period when it will no more be fitted for the dwelling-place of men.
§ 6. It is, therefore, not so much what these forms of the earth actually are, as what they are continually becoming, that we have to observe; nor is it possible thus to observe them without an instinctive reference to the first state out of which they have been brought. The existing torrent has dug its bed a thousand feet deep. But in what form was the mountain originally raised which gave that torrent its track and power? The existing precipice is wrought into towers and bastions by the perpetual fall of its fragments. In what form did it stand before a single fragment fell?
Yet to such questions, continually suggesting themselves, it is never possible to give a complete answer. For a certain distance, the past work of existing forces can be traced; but there gradually the mist gathers, and the footsteps of more gigantic agencies are traceable in the darkness; and still, as we endeavor to penetrate farther and farther into departed time, the thunder of the Almighty power sounds louder and louder; and the clouds gather broader and more fearfully, until at last the Sinai of the world is seen altogether upon a smoke, and the fence of its foot is reached, which none can break through.
§ 7. If, therefore, we venture to advance towards the spot where the cloud first comes down, it is rather with the purpose of fully pointing out that there is a cloud, than of entering into it. It is well to have been fully convinced of the existence of the mystery, in an age far too apt to suppose that everything which is visible is explicable, and everything that is present, eternal. But besides ascertaining the existence of this mystery, we shall perhaps be able to form some new conjectures respecting the facts of mountain aspects in the past ages. Not respecting the processes or powers to which the hills owe their origin, but respecting the aspect they first assumed.
§ 8. For it is evident that, through all their ruin, some traces must still exist of the original contours. The directions in which the mass gives way must have been dictated by the disposition of its ancient sides; and the currents of the streams that wear its flanks must still, in great part, follow the course of the primal valleys. So that, in the actual form of any mountain peak, there must usually be traceable the shadow or skeleton of its former self; like the obscure indications of the first frame of a war-worn tower, preserved, in some places, under the heap of its ruins, in others to be restored in imagination from the thin remnants of its tottering shell; while here and there, in some sheltered spot, a few unfallen stones retain their Gothic sculpture, and a few touches of the chisel, or stains of color, inform us of the whole mind and perfect skill of the old designer. With this great difference, nevertheless, that in the human architecture the builder did not calculate upon ruin, nor appoint the course of impendent desolation; but that in the hand of the great Architect of the mountains, time and decay are as much the instruments of His purpose as the forces by which He first led forth the troops of hills in leaping flocks:—the lightning and the torrent, and the wasting and weariness of innumerable ages, all bear their part in the working out of one consistent plan; and the Builder of the temple for ever stands beside His work, appointing the stone that is to fall, and the pillar that is to be abased, and guiding all the seeming wildness of chance and change, into ordained splendors and foreseen harmonies.
§ 9. Mountain masses, then, considered with respect to their first raising and first sculpture, may be conveniently divided into two great groups; namely, those made up of beds or layers, commonly called stratified; and those made of more or less united substance, called unstratified. The former are nearly always composed of coherent rocks, the latter of crystallines; and the former almost always occupy the outside, the latter the centre of mountain chains. It signifies, therefore, very little whether we distinguish the groups by calling one stratified and the other unstratified, or one "coherent" and the other "crystalline," or one "lateral" and the other "central." But as this last distinction in position seems to have more influence on their forms than either of the others, it is, perhaps, best, when we are examining them in connection with art, that this should be thoroughly kept in mind; and therefore we will consider the first group under the title of "lateral ranges," and the second under that of "central peaks."
| Fig. 8. |
§ 10. The lateral ranges, which we are first to examine, are, for the most part, broad tabular masses of sandstone, limestone, or whatever their material may be,—tilted slightly up over large spaces (several or many miles square), and forming precipices with their exposed edges, as a book resting obliquely on another book forms miniature precipices with its back and sides. The book is a tolerably accurate representation of the mountain in substance, as well as in external aspect; nearly all these tabular masses of rock being composed of a multitude of thinner beds or layers, as the thickness of the book is made up of its leaves; while every one of the mountain leaves is usually written over, though in dim characters, like those of a faded manuscript, with history of departed ages.
"How were these mountain volumes raised, and how are they supported?" are the natural questions following such a statement.
And the only answer is: "Behold the cloud."
No eye has ever seen one of these raised on a large scale; no investigation has brought completely to light the conditions under which the materials which support them were prepared. This only is the simple fact, that they are raised into such sloping positions; generally several resting one upon another, like a row of books fallen down ([Fig. 8]); the last book being usually propped by a piece of formless compact crystalline rock, represented by the piece of crumpled paper at a.
| Fig. 9. |
§ 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 glass. 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 circumstances, presenting, not the uniform edges of the books, but jagged edges, as in [Fig. 9].
| Fig. 10. |
§ 12. Do not let it be said that I am passing 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 constitute 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 mass, 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 mass, 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.
| Fig. 11. |
| Fig. 12. |
I do not say that this operation has actually taken place. I merely say that such cliffs do in multitudes 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 débris 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 analogous 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!
| 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 shores 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.
§ 18. Hitherto, however, for the sake of clearness, we have spoken of hills as if they were composed of a single mass or The three great representative forms of stratified mountains. 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.
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 1. Wall above slope. mass 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.
| Fig. 14. |
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 mass below, 2. Slope above wall. and the hill would assume the form d, large masses of débris being in either of these two cases accumulated 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 classes 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.
3d. When the elevated mass, 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 3. Slope and wall alternately. each other, and the mountain rises on a series of steps, with receding slopes of turf or débris on the ledge of each, as at b. At the head of the valley of Sixt, in Savoy, huge masses 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 haycocks 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.
| 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 masses, thousands of feet thick. And it is almost universally true of these masses 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 associated with the wildest waves. We might have expected that sometimes we should have had noble 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 noblest 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.
| 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 associated with the most violent contortions, they sometimes follow the contortions, and sometimes appear entirely independent of them. For instance, in crossing the pass of the Tête Noire, if the traveller defers his journey till near the afternoon, so that from the top of the pass 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 mass, 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 mass 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 classical 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.
| Fig. 18. | 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 space 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 passed 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 passed 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?"
[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.