president's address. 13 



In that case, if we assume the altitudes unchanged, not a snowfield 

 would be left between the Simplon and the Maloja, the glaciers of the 

 Pennines would shrivel into insignificance, Monte Eosa would exchange 

 its drapery of ice for little more than a tippet of frozen snow. As the 

 temperature fell the white robes would steal down the mountain-sides, 

 the glaciers grow, the torrents be swollen during all the warmer months, 

 and the work of sculpture increase in activity. Yet with a tempera- 

 ture even 6° higher than it now is, as it might well be at the beginning 

 of the Pliocene period, the snow-line would be at 10,000 feet; numbers 

 of glaciers would have disappeared, and those around the Jungfrau and 

 the Finster Aarhorn would be hardly more important than they now are 

 in the Western Oberland. 



But denudation would begin so soon as the ground rose above the sea. 

 Water, which cannot run off the sand exposed by the retreating tide 

 without engraving a miniature system of valleys, would never leave the 

 nascent range intact. The Miocene Alps, even before a patch of snow 

 could remain through the summer months, would be carved into glens 

 and valleys. Towards the end of that period the Alps were affected by 

 a new set of movements, which produced their most marked effects in 

 the northern zone from the Inn to the Durance. The Oberland rose to 

 greater importance; Mont Blanc attained its primacy; the massif of 

 Dauphin^ was probably developed. That, and still more the falling 

 temperature, would increase the snowfields, glaciers, and torrents. The 

 first would be, in the main, protective; the second, locally abrasive; the 

 third, for the greater part of their course, erosive. No sooner had the 

 drainage system been developed on both sides of the Alps than the valleys 

 on the Italian side (unless we assume a very different distribution of 

 rainfall) would work backwards more rapidly than those on the northern. 

 Cases of trespass, such as that recorded by the long level trough on 

 the north side of the Maloja Kulm and the precipitous descent on the 

 southern, would become frequent. In the interglacial episodes — three 

 in number, according to Penck and Bruckner, and occupying rather more 

 than half the epoch — the snow and ice would dwindle to something like 

 its present amount, so that the water would resume its work. Thus 

 I think it far more probable that the V-like portions of the Alpine 

 valleys were in the main excavated during Pliocene ages, their upper 

 and more open parts being largely the results of Miocene and yet earlier 

 sculpture. 



During the great advances of the ice, four in number, according 

 to Penck and Bruckner, * when the Ehone glacier covered the lowlands of 

 Vaud and Geneva, welling on one occasion over the gaps in the Jura, 

 And leaving its erratics in the neighbourhood of Lyons, it ought to have 



f On the exact number I have not had the opportunity of forming an opinion. 



