Sec. 9. It may be noted in passing, that this wall which with its regular fosse defends the Riffelhorn on its western side, and a similar one on its eastern side, though neither of them of any considerable height, are curious instances of trenchant precipice, formed, I suppose, by slight slips or faults of the serpentine rock. The summit of the horn, _a_, Fig. 78, seems to have been pushed up in a mass beyond the rest of the ridge, or else the rest of the ridge to have dropped from it on each side, at _b c_, leaving the two troublesome faces of cliff right across the crag, hard, green as a sea wave, and polished like the inside of a seashell, where the weather has not effaced the surface produced by the slip. It is only by getting past the eastern cliff that the summit can be reached at all, for on its two lateral escarpments the mountain seems quite inaccessible, being in its whole mass nothing else than the top of a narrow wall with a raised battlement, as rudely shown in perspective at _e d_; the flanks of the wall falling towards the glacier on one side, and to the lower Riffel on the other, four or five hundred feet, not, indeed, in unbroken precipice, but in a form quite incapable of being scaled.[84] [Illustration: FIG. 79.] Sec. 10. To return to the Cervin. The view of it given on the left hand in Plate +38+ shows the ridge in about its narrowest profile; and shows also that this ridge is composed of beds of rock shelving across it, apparently horizontal, or nearly so, at the top, and sloping considerably southwards (to the spectator's left), at the bottom. How far this slope is a consequence of the advance of the nearest angle giving a steep perspective to the beds, I cannot say; my own belief would have been that a great deal of it is thus deceptive, the beds lying as the tiles do in the somewhat anomalous, but perfectly conceivable house-roof, Fig. 79. Saussure, however, attributes to the beds themselves a very considerable slope. But be this as it may, the main facts of the thinness of the beds, their comparative horizontality, and the daring swordsweep by which the whole mountain has been hewn out of them, are from this spot comprehensible at a glance. Visible, I _should_ have said; but eternally, and to the uttermost, _in_comprehensible. Every geologist who speaks of this mountain seems to be struck by the wonderfulness of its calm sculpture--the absence of all aspect of convulsion, and yet the stern chiselling of so vast a mass into its precipitous isolation leaving no ruin nor debris near it. "Quelle force n'a-t-il pas fallu," exclaims M. Saussure, "pour rompre, et pour _balayer_ tout ce qui manque a cette pyramide!" "What an overturn of all ancient ideas in Geology," says Professor Forbes, "to find a pinnacle of 15,000 feet high [above the sea] sharp as a pyramid, and with perpendicular precipices of thousands of feet on every hand, to be a representative of the older chalk formation; and what a difficulty