president's address. 11 



being equal, with the latitude. The grinding away of ridges and spurs, 

 the smoothing of the walls of troughs, 1 is greater in Norway than in the 

 Alps; it is still greater in Greenland than in Norway, and it is greatest 

 of all in the Antarctic, according to the reports of the expeditions led by 

 Scott and Shackleton. But even in Polar regions, under the most 

 favourable conditions, the dominant outlines of the mountains, as shown 

 in the numerous photographs taken by both parties, and in Dr. Wilson's 

 admirable drawings, differ in degree rather than in kind from those of 

 mid-European ranges. It has been asserted that the parallel sides of 

 the larger Alpine valleys— such as the Ehone above Martigny, the 

 Lutschine near Lauterbrunnen, and the Val Bedretto below Airolo — 

 prove that they have been made by the ice-plough rather than by running 

 water; but in the first I am unable to discern more than the normal 

 effects of a rather rapid river which has followed a trough of compara- 

 tively soft rocks; in the second, only the cliffs marking the channel cut 

 by a similar stream through massive limestones — cliffs like those which 

 elsewhere rise up the mountain flanks far above the levels reached by 

 glaciers; while in the third I have failed to discover, after repeated 

 examination, anything abnormal. 



Many lake basins have been ascribed to the erosive action of glaciers. 

 Since the late Sir A. Eamsay advanced this hypothesis numbers of lakes 

 in various countries have been carefully investigated and the results pub- 

 lished, the most recent of which is the splendid work on the Scottish 

 lochs by Sir J. Murray and Mr. L. Pullar. 2 A contribution to science 

 of the highest value, it has also a deeply pathetic interest, for it is a 

 father's memorial to a much-loved son, P. P. Pullar, who, after taking a 

 most active part in beginning the investigation, lost his life while saving 

 others from drowning. As the time at my command is limited, and 

 many are acquainted with the literature of the subject, I may be excused 

 from saying more than that even these latest researches have not driven 

 me from the position which I have maintained from the first — namely, 

 that while many tarns in corries and lakelets in other favourable situa- 

 tions are probably due to excavation by ice, as in the mountainous dis- 

 tricts of Britain, in Scandinavia, or in the higher parts of the Alps, the 

 difficulty of invoking this agency increases with the size of the basin — 

 as, for example, in the case of Loch Maree or the Lake of Annecy — till 

 it becomes insuperable. Even if Glas Llyn and Llyn Llydaw were the 

 work of a glacier, the rock basins of Gennesaret and the Dead Sea, still 

 more those of the great lakes in North America and in Central Africa, 

 must be assigned to other causes. 



1 If one may judge from photographs, the smoothing of the flanks of a valley is 

 unusually conspicuous in Milton Sound, New Zealand. 



2 Bathymetrical Survey of the Scottish Freshwater Lochs. Sir J. Murray and 

 Mr. L. Pullar, 1910. 



