1871.] 



BONNET POEMATION OF " CIEQUES." 



319 



Fig. 2. — Diagram of Le Bateau. 





p. Precipice of Le Eateau. 

 S. 8teep snow slopes, 

 cier du Mont de Lans, 



P'. Eocky Spurs with precipices towards Glacier. 

 G, Glacier. ■»— * Snow-basin leading to Gla- 



If, then, it be conceded that the neve of a glacier can settle down 

 BO fast that the uppermost mile or two of its bed shall be almost a cliff 

 compared with the remainder of the stream, and we thus account 

 for the configuration of such valleys as those above named, and, on 

 a smaller scale, those in which lie the Brenva, Miage, and Argentiere 

 glaciers near Mont Blanc, the TJnter-Grindelwald and Lauter Aar 

 glaciers in the Oberland, the Trift glacier near Zermatt, and dozens 

 more which could be easily named in all parts of the Alps, how are 

 we to explain such contradictions as the Mont de Lans, the Theo- 

 dule, the Gorner (between Monte Eosa and the Strahlhorn), and the 

 Titlis glaciers ? or such anomalies as the low opening of the Am- 

 pezzo Pass (about 5000 feet) among the towering summits of the 

 Drei Zinnen, CristaUo, and Geiselstein * ? Surely it is far safer to 

 suppose that the glen, by whatever cause fashioned, gave rise to the 

 glacier, rather than the glacier to the glen. 



But perhaps it will be urged that the greater steepness of the 

 heads of the valleys may be explained by the fact that, in the gra- 

 dual retreat of the ice-streams since the glacial epoch, they have 

 been exposed to erosive action for a longer time than the lower 

 parts ; and so the glaciers, in comparatively recent periods, have 

 steepened the slope of their upper glens. The suggestion is plausi- 

 ble, and might be supported by an appeal to tarns like those of the 

 Lago Bianco and Nero on the Bernina Pass, and by occasional flat 



* All about 10,000 feet above the sea. 



