A more serious hindrance to mounting the south-west ridge is found in the dip of its rocks to the west-south-west. The great mass of the Matterhorn, it is now well ascertained, is composed of regularly stratified rocks, which rise toward the east. It has been mentioned in the text, more than once, that the rocks on some portions of the ridge leading from the Col du Lion to the summit dip outward, and that fractured edges overhang. This is shown very clearly in the annexed diagram, Fig. 1. It will be readily understood that such an arrangement is not favorable for climbers, and that the degree of facility with which rocks can be ascended that are so disposed must depend very much upon the frequency or paucity of fissures and joints. The rocks of the south-west ridge are sufficiently provided with cracks, but if it were otherwise, their texture and arrangement would render them unassailable.[[50]]
[50] Weathered granite is an admirable rock to climb; its gritty texture giving excellent hold to the nails in one’s boots. But upon such metamorphic schists as compose the mass of the great peak of the Matterhorn, the texture of the rock itself is of no value.
Fig. 1.
It is not possible to go a single time upon the rocks of the south-west ridge, from the Col du Lion to the foot of the Great Tower, without observing the prevalence of their outward dip, and that their fractured edges have a tendency to overhang; nor can one fail to notice that it is upon this account the débris which is rent off by frost does not remain in situ, but pours down in showers over the surrounding cliffs. Each day’s work, so to speak, is cleared away—the ridge is swept clean: there is scarcely anything seen but firm rock.[[51]]
[51] I refer here only to that portion of the ridge which is between the Col du Lion and the Great Tower. The remarks would not apply to the rocks higher up (see p. 118); higher still the rocks are firm again; yet higher (upon the “Shoulder”) they are much disintegrated; and then, upon the final peak, they are again firm.
The fact that the mountain is composed of a series of stratified beds was pointed out long ago. De Saussure remarked it, and recorded explicitly in his Travels (§ 2243) that they “rose to the north-east at an angle of about forty-five degrees.” Forbes noticed it also, but gave it as his opinion that the beds were “less inclined, or nearly horizontal.” He added, “De Saussure is no doubt correct.” The truth, I think, lies between the two.
I was acquainted with both of the above-quoted passages, but did not turn the knowledge to any practical account until I re-observed the same fact for myself. It was not until after my repulse in 1863 that I referred the peculiar difficulties of the south-west ridge to the dip of the strata, but when once persuaded that structure and not texture was the real impediment, it was reasonable to infer that the opposite side—that is to say, the eastern face—might be comparatively easy; in brief, that an arrangement should be found like Fig. 2, instead of like Fig. 1. This trivial deduction was the key to the ascent of the Matterhorn.
