MONT BLANC AXD THE MER DE GLACE. 53 



A record on a stone at the outer moraine informs us that 

 this epoch was 1826. At that time, says Payot,* the ter- 

 minal moraine had been crowded close to the little ham- 

 let des Bois, to the great consternation of its inhabitants, 

 and some huge blocks, still to be seen, were hurled down 

 among the houses. From that date to 1869 the retreat 

 had amounted to 1,640 feet. In the same time, the ver- 

 tical thickness of the glacier has diminished 984 feet. 

 There rises before us an immense protrusion of rock, 

 standing exactly in the natural course of the glacier. 

 Its surface is planed completely smooth, and the guides 

 tell us that within their memory the river of ice flowed 

 triumphantly over it. Now it turns to the right, and de- 

 scribes a semi-circle to avoid the obstacle. 



Let us now view these objects from the opposite side 

 of the valley of Chamonix. The ascent of the Flegere is 

 one of the favorite excursions. It is only six thousand 

 feet high, being a little less elevated than Mon tan vert. 

 The path is similar, and the scenes are similar. From 

 the inn on the summit we obtain magnificent views of 

 the whole chain of Mont Blanc. The Mer de Glace winds 

 snake-like down its valley, and the needled pinnacles sur- 

 rounding its upper course stand forth in characteristic 

 boldness. We have more than once remarked the con- 

 trast in form between the aiguillated summits and the 

 rounded dome of Mont Blanc. A difference in geological 

 structure is, of course, the cause of this. A geological 

 section, across any part of the Alpine chain, shows it to 

 be constituted of three portions. a Middle Zone, a North 

 Lateral Zone, and a South Lateral Zone. The rocks of 

 the Middle Zone stand almost vertical, while those of the 



* Payot. Gtndf 7fin^ra>rf nn ^fr>nt fllanc, p. 153. 



