ANCIENT GLACIERS IN EASTERN HEMISPHERE. 131 



Central and Southern Europe. 



The main centres of ice-movement in the Alps during 

 the Glacial period are the same as those which furnish 

 the lingering glaciers of the present time. From the 

 water-shed between the Ehine, the Ehone, and the Aar, 

 glaciers of immense size descended all the valleys now 

 occupied by those streams. The valley of the Ehone be- 

 tween the Bernese and the Pennine Alps was filled with a 

 glacier of immense depth, which was maintained by fresh 

 supplies from tributaries upon either side as far down as 

 Martigny. Glacial markings at the head of the Ehone 

 Valley are found upon the Schneestock,* at an elevation 

 above the sea of about 11,500 feet (3,550 metres), or 

 about 1,500 feet above the present surface of the Ehone 

 Glacier. At Fiesch, about twenty miles below, where 

 tributaries from the Bernese Oberland snow-fields were 

 received, the thickness of the glacier was upwards of 5,000 

 feet (1,680 metres). Near Martigny, about fifty miles 

 farther down the valley, where the glacier was abruptly de- 

 flected to the north, the depth of the ice was still upwards 

 of 1,600 metres. From Martigny northward the thick- 

 ness of the ice decreased rapidly for a few miles, where, 

 at the enlargement of the valley above the head of Lake 

 Geneva, it was less than 1,200 metres in thickness, and 

 spread out over the intervening plain as far as Chasseron, 

 with a nearly level surface, transporting, as we have before 

 said, Alpine boulders to the flanks of the Juras, and land- 

 ing them about 3,000 feet (1,275 metres) above the level 

 of Lake Geneva. The width of the main valley is here 

 about fifty miles, making the slope of the surface of the 

 ice about twenty feet to the mile. 



From its " vomitory," at the head of Lake Geneva, the 



* A. Falsan's La Periode Grlaciaire etudiee principaleinent en 

 France et en Suisse, chapitre xv. 



