Ancient Extent of the Glaciers of Chamonix, 77 



border of tho wood below the village of that name ; another, 

 situate near the hjimlet of Caches, at a little distance from 

 Sallenches, is celebrated in the country under the name of 

 Pierre a Mahert. 



The great accumulation of blocks which renders the mo- 

 raine of Combloux one of the most remarkable among the 

 Alps, is easily explained, if we considerthat at this point the 

 buttress of the valley is exactly in front of the gorge of 

 Servoz, by which the glacier of the Arve issued into the 

 plain of Sallenches. This moraine was, therefore, at the 

 same time both a lateral and frontal one, like that of the 

 present glacier of Lauteraar, near Baerenritz. The imagi- 

 nation can scarcely compute the space of time during which 

 the glacier deposited in this place the blocks severed from 

 the Aiguilles, which surround Mont Blanc. Some have pe- 

 netrated, along with them, the glacier of Bonnaut, in the 

 high valley of Megeve, which opens between St Gervais and 

 Combloux ; but they have not surpassed much the division 

 of the waters of the Arve and Isere. The valley of the Me- 

 geve not terminating in a cirque crowned with high moun- 

 tains, it will be understood, that it does not give rise to a 

 glacier, like the valley of Montjoie ; but, as it opens on one 

 side into the valley of the Arve, and on the other into that of 

 the Isere, it is probable that two branches of glaciers of the 

 same name met at the place where the burgh of Megeve is 

 now situate ; for beyond that, towards the Isere, we find none 

 of those blocks of protogine which characterize the glaciers 

 of Mont Blanc. 



Continuing to descend the course of the Arve, we enter 

 the valley of Maglan ; and we may satisfy ourselves that the 

 moraine of Combloux does not terminate at Sallenches. In- 

 numerable blocks of protogine cover all the declivities above 

 the left bank of the river. In the defile of Cluses, many of 

 these blocks are visible from the great road, and I have fol- 

 lowed them to a height of 286 metres ; which is certainly 

 not the extreme limit of the moraine. These erratic blocks 

 are wholly wanting on the right bank, throughout the whole 

 valley of Maglan. Whence arises this difference % Why do 

 wo find thousands of blocks of protogine on the loft bank of 



