428 Reviews — Lubbock's Scenery of Switzerland, 



say that it is because they are so old that they have been so much 

 worn down ; the Alps themselves are crumbling, and being washed 

 away ; and if no fresh elevation takes place, the time will come 

 when they will be no loftier than Snowdon or Helvellyn, 



"They have already undergone enormous denudation, and it has 

 been shown that from the summit of Mont Blanc some 10,000 to 12,000 

 feet of strata have been already removed. The conglomerates of 

 Central Switzerland, the gravels and sands of the Rhine and the 

 Rhone, the Danube and the Po, the plains of Dobrudscha, of 

 Lombardy, of South France, of Belgium and Holland, once formed 

 the summits of Swiss mountains. This amount of denudation gives us, 

 I will not say a measure, but at any rate a vivid idea of the immense 

 time that must have elapsed since the Alps rose out of the sea. 



" Denudation began as soon as the land rose above the sea ; the 

 main river valleys were excavated. Then came the period of cold 

 known as the Ice Age or Glacial period. 



" Round all the high mountains, and over many of them, are 

 great fields of ice and snow, terminating in glaciers. These, how- 

 ever, are but the remnants of a much larger sea of ice which once 

 covered almost the whole country. The glacier of the Rhone, for 

 instance, descended the Valais, filled the Lake of Geneva, rose to 

 what is now a height of 1350 metres on the Jura, and then dividing, 

 sent one branch as far as Lyons, and a second along the Aar to 

 Waldshut. The Glacial period, however, was not continuous, but 

 interrupted by at least two periods of more genial climate. The 

 mass of material brought down from the mountains partially filled 

 the river valleys (which have not even yet been entirely re-excavated), 

 formed great moraines, and is spread in thick but irregular masses 

 over all the lower ground. 



" The rivers of Switzerland run mainly in one of two directions — 

 the first from south-west to north-east, or vice versa, following the 

 strike and original folds of the strata ; and the second at right angles 

 to it. Many, indeed most, of the principal rivers, take first the one 

 and then the other direction in different parts of their course. In 

 some cases the rivers cut through mountain ranges, as, for instance, 

 the Rhone between Martigny and the Lake of Geneva. This 

 probably indicates that the river is older than the mountain range, 

 and cut through it as it rose. 



" The river system of Switzerland was, however, at first very 

 different from the present. The Vosges and the Black Forest were 

 continuous, the subsidence which now separates them not having yet 

 taken place, so that the Rhine Valley at Basle was not in existence. 



" Nor had the gorges by which the Rhone finds its exit through 

 the Vuache yet been formed, and the consequence was that the 

 whole drainage of Switzerland north of the Alps found its waj' by 

 the Danube to the Black Sea. For some time after the subsidence 

 of the Basle Valley had taken place the upper watei's of the Rhone 

 still joined the Rhine, and ran over the plains of Germany to the 

 North Sea ; finally, however, it broke its way by Fort de L'Ecluse, 

 and falling into the Saoue runs into the Mediterranean. Another 





