And I was confirmed in this feeling by De Saussure; the only writer whose help I did not refuse in the course of these inquiries. His I received for this reason,—all other geological writers whose works I had examined were engaged in the maintenance of some theory or other, and always gathering materials to support it. But I found Saussure had gone to the Alps as I desired to go myself, only to look at them, and describe them as they were, loving them heartily—loving them, the positive Alps, more than himself, or than science, or than any theories of science; and I found his descriptions, therefore, clear, and trustworthy; and that when I had not visited any place myself, Saussure's report upon it might always be received without question.
Not but that Saussure himself has a pet theory, like other human beings; only it is quite subordinate to his love of the Alps: He is a steady advocate of the aqueous crystallization of rocks, and never loses a fair opportunity of a blow at the Huttonians; but his opportunities are always fair, his description of what he sees is wholly impartial; it is only when he gets home and arranges his papers that he puts in the little aqueously inclined paragraphs, and never a paragraph without just cause. He may, perhaps, overlook the evidence on the opposite side; but in the Alps the igneous alteration of the rocks, and the modes of their upheaval, seem to me subjects of intense difficulty and mystery, and as such Saussure always treats them; the evidence for the original deposition by water of the slaty crystallines appears to him, as it does to me, often perfectly distinct.
Now, Saussure's universal principle was exactly the one on which I have founded my account of the slaty crystallines:—"Fidèle à mon principle, de ne regarder comme des couches, dans les montagnes schisteuses, que les divisions parallèles aux feuillets des schistes dont elles sont composées."—Voyages, § 1747. I know that this is an arbitrary, and in some cases an assuredly false, principle; but the assumption of it by De Saussure proves all that I want to prove,—namely, that the beds of the slaty crystallines are in the Alps in so large a plurality of instances correspondent in direction to their folia, as to induce even a cautious reasoner to assume such correspondence to be universal.
The next point, however, on which I shall be opposed, is one on which I speak with far less confidence, for in this Saussure himself is against me,—namely, the parallelism of the beds sloping under the Mont Blanc. Saussure states twice, §§ 656, 677, that they are arranged in the form of a fan. I can only repeat that every measurement and every drawing I made in Chamouni led me to the conclusions stated in the text, and so I leave the subject to better investigators; this one fact being indisputable, and the only one on which for my purpose it is necessary to insist, that, whether in Chamouni the beds be radiant or not, to an artist's eye they are usually parallel; and throughout the Alps no phenomenon is more constant than the rounding of surfaces across the extremities of beds sloping outwards, as seen in my plates [37], [40], and [48], and this especially in the most majestic mountain masses. Compare De Saussure of the Grimsel, § 1712: "Toujours il est bien remarquable que ces feuillets, verticaux au sommet, s'inclinent ensuite, comme à Chamouni, contre le dehors de la montagne:" and again of the granite at Guttannen, § 1679: "Ces couches ne sont pas tout-a-fait verticales; elles s'appuyent un peu contre le Nord-Est, ou, comme à Chamouni, contre le dehors de la montagne." Again, of the "quartz micacé" of Zumloch, § 1723: "Ces rochers sont en couches à peu près verticales, dont les plans courent du Nord-Est au Sud-Ouest, en s'appuyant, suivant l'usage, contre l'extérieur de la montagne, ou contre la vallée." Again, on the Pass of the Griés, § 1738: "Le rocher présente des couches d'un schiste micacé rayé comme une étoffe; comme de l'autre côté ils surplombent vers le dehors de la montagne." Without referring to other passages I think Saussure's simple words, "suivant l'usage," are enough to justify my statement in Chap. XIV. § 3; only the reader must of course always remember that every conceivable position of beds takes place in the Alps, and all I mean to assert generally is, that where the masses are most enormous and impressive, and formed of slaty crystalline rocks, there the run of the beds up, as it were, from within the mountain to its surface, will, in all probability, become a notable feature in the scene as regarded by an artist. One somewhat unusual form assumed by horizontal beds of slaty crystallines, or of granite, is described by Saussure with unusual admiration; and the passage is worth extracting, as bearing on the terraced ideal of rocks in the middle ages. The scene is in the Val Formazza.
"Indépendamment de l'intérêt que ces couches présentent au géologiste sous un nombre de rapports qu'il seroit trop long et peut-être inutile de détailler, elles présentent même pour le peintre, un superbe tableau. Je n'ai jamais vu de plus beaux rochers et distribués en plus grandes masses; ici, blancs; là, noircis par les lichens; là, peints de ces belles couleurs variées, que nous admirions au Grimsel, et entremêlés d'arbres, dont les uns couronnent le faîte de la montagne, et d'autres sont inégalement jetés sur les corniches qui en séparent les couches. Vers le bas de la montagne l'œil se repose sur de beaux vergers, dans des prairies dont le terrein est inégal et varié, et sur de magnifiques chàtaigniers, dont les branches étendues ombragent les rochers contre lesquels ils croissent. En général, ces granits en couches horizontals redent ce pays charmant; car, quoiqu'il y ait, comme je l'ai dit, des couches qui forment des saillies, cependant elles sont pour l'ordinaire arrangées en gradins, ou en grandes assises posées en reculement les unes derrière les autres, et les bords de ces gradins sont couverts de la plus belle verdure, et d'arbres distribués de la manière la plus pittoresque. On voit è mme des montagnes très-élevées, qui out la forme de pain de sucre, et qui sont entourées et couronnées jusqu'à leur sommet, de guirlandes d'arbres assis sur les intervalles des couches, et qui forment l'effet du monde le plus singulier."-Voyages, § 1758.
Another statement, which I made generally, referring, for those qualifications which it is so difficult to give without confusing the reader, to this appendix, was that of the usually greater hardness of the tops of mountains as compared with their flanks. My own experience among the Alps has furnished me with few exceptions to this law; but there is a very interesting one, according to Saussure, in the range of the Furca del Bosco. (Voyages, § 1779.)
Lastly, at page 186 of this volume, I have alluded to the various cleavages of the aiguilles, out of which one only has been explained and illustrated. I had not intended to treat the subject so partially; and had actually prepared a long chapter, explaining the relations of five different and important systems of cleavage in the Chamouni aiguilles. When it was written, however, I found it looked so repulsive to readers in general, and proved so little that was of interest even to readers in particular, that I cancelled it, leaving only the account of what I might, perhaps, not unjustifiably (from the first representation of it in the Liber Studiorum) call Turner's cleavage. The following passage, which was the introduction to the chapter, may serve to show that I have not ignored the others, though I found, after long examination, that Turner's was the principal one:—
"One of the principal distinctions between these crystalline masses and stratified rocks, with respect to their outwardly apparent structure, is the subtle complexity and number of ranks in their crystalline cleavages. The stratified masses have always a simple intelligible organization; their beds lie in one direction, and certain fissures and fractures of those beds lie in other clearly ascertainable directions; seldom more than two or three distinct directions of these fractures being admitted. But if the traveller will set himself deliberately to watch the shadows on the aiguilles of Chamouni as the sun moves round them, he will find that nearly every quarter of an hour a new set of cleavages becomes visible, not confused and orderless, but a series of lines inclining in some one definite direction, and that so positively, that if he had only seen the aiguille at that moment, he would assuredly have supposed its internal structure to be altogether regulated by the lines of bed or cleavage then in sight. Let him, however, wait for another quarter of an hour, and he will see those lines fade entirely away as the sun rounds them; and another set, perhaps quite adverse to them and assuredly lying in another direction, will as gradually become visible, to die away in their turn, and be succeeded by a third scheme of structure.
"These 'dissolving views' of the geology of the aiguilles have often thrown me into despair of ever being able to give any account of their formation; but just in proportion as I became aware of the infinite complexity of their framework, the one great fact rose into more prominent and wonderful relief,—that through this inextricable complexity there was always manifested some authoritative principle. It mattered not at what hour of the day the aiguilles were examined, at that hour they had a system of structure belonging to the moment. No confusion nor anarchy ever appeared amidst their strength, but an ineffable order, only the more perfect because incomprehensible. They differed from lower mountains, not merely in being more compact, but in being more disciplined.
"For, observe, the lines which cause these far-away effects of shadow, are not, as often in less noble rocks, caused by real cracks through the body of the mountain; for, were this so, it would follow, from what has just been stated, that these aiguilles were cracked through and through in every direction, and therefore actually weaker, instead of stronger, than other rocks. But the appearance of fracture is entirely external, and the sympathy or parallelism of the lines indicates, not an actual splitting through the rock, but a mere disposition in the rock to split harmoniously when it is compelled to do so. Thus, in the shell-like fractures on the flank of the Aiguille Blaitière, the rock is not actually divided, as it appears to be, into successive hollow plates. Go up close to the inner angle between one bed of rock and the next, and the whole mass will be found as firmly united as a piece of glass. There is absolutely no crack between the beds,—no, not so much as would allow the blade of a penknife to enter for a quarter of an inch;[124] but such a subtle disposition to symmetry of fracture in the heart of the solid rock, that the next thunderbolt which strikes on that edge of it will rend away a shell-shaped fragment or series of fragments; and will either break it so as to continue the line of one of the existing sides, or in some other line parallel to that. And yet this resolvedness to break into shell-shaped fragments running north and south is only characteristic of the rock at this spot, and at certain other spots where similar circumstances have brought out this peculiar humor. Forty yards farther on it will be equally determined to break in another direction, and nothing will persuade it to the contrary. Forty yards farther it will change its mind again, and face its beds round to another quarter of the compass; and yet all these alternating caprices are each parts of one mighty continuous caprice, which is only masked for a time, as threads of one color are in a patterned stuff by threads of another; and thus from a distance, precisely the same cleavage is seen repeated again and again in different places, forming a systematic structure; while other groups of cleavages will become visible in their turn, either as we change our place of observation, or as the sunlight changes the direction of its fall."