Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/463

 gently * from a central plateau to opposite points of the compass, can conceive it to have been excavated by a glacier.

In consequence of these reasons, in addition to those already advanced by Sir R. Murchison, Sir C. Lyell, Mr. Ball, M. Favre, &c, I venture to maintain that it is impossible for glaciers to have excavated cirques, and difficult to understand how they can have excavated valleys. I now take one step further, and shall endeavour to show that, if they excavated the valleys, they must also have excavated the cirques. Consider, for example, the case of the Creux de Champs. This is not, as it at first sight appears, in a lateral glen, but at the true head of the Grande-Eau valley. The principal excavating agent, be it ice or water, must have always followed the line of the present drainage of the cirque, and not of that from the lower alps of the Col de Pillon.

Efface the cirque, replace in imagination the vast mass of material which has been scooped out of the heart of the Diablerets between Ormond Dessus and the peaks of the mountains fill up the valley of the Grande Eau, far above the village just named to near the level of the Col de Pillon, there will then be a rather regular and shallow trench, bounded on the one side by the Tornette chain, on the other by the Diablerets' massif, a far huger block than now. Prom this the western and north-western drainage, whether in a liquid or solid form, would have descended, chiefly along the valleys mentioned above, and partly by the small glen west of the Oldenhorn, which, at the present day, has a cirque-like configuration, while only a little would have been supplied by the low alps of the Col de Pillon. Any glacier, therefore, which excavated the Grande-Eau valley below Ormond Dessus must have received its chief ice- affluent from the direction of the present cirque ; and I am convinced that no one who has seen the locality could ever attribute the formation of the two parts of the valley above and below this village to different agencies. If, then, we have established that the excavation of a cirque by a glacier is mechanically impossible, the cirque, if not prior to it, must have been excavated by some other agent since the ice-period. But if the streams have been able to remove this enormous amount of debris above Ormond Dessus, how can we account for their comparative inefficiency below ? If they have been so active here, and in a few other glens, how is it that they have been practically inactive in the Rhone valley and its other tributaries, and in the great majority of Alpine valleys ? Above all, how are we to account for the presence of moraines in the cirque itself?

The same remarks would apply to the Fer-a-Cheval and Am Ende der Welt, whose floors join, were it possible, even more uniformly with those of the main valleys, in which signs of glacial action are still abundantly visible.

The conclusion then seems to me inevitable, that the cirques, and

(9$ miles) 2502 feet, Bruneck (14 miles) 2686 feet, Niederndorf (14 miles) 3784 feet, Toblach 3951 feet, Inuichen 3701 feet, Sillian (14 miles) 3611 feet.
 * The levels of points in the valley are, Muhlbach 2542 feet, Untervintl