. . . president's address. 5 



districts, it has been possible for me to carry on the latter without 

 neglecting the former, and my study of ice-work gradually led me from 

 the highlands into the lowlands. 1 I purpose, then, to ask your attention 

 this evening to some aspects of the glacial history of Western Europe. 



At no very distant geological epoch the climate in the northern 

 part of the earth was much colder than it is at present. So it was 

 also in the southern ; but whether the two were contemporaneous is less 

 certain. Still more doubtful are the extent and the work of the ice which 

 was a consequence, and the origin of certain deposits on some northern 

 lowlands, including those of our own islands : namely, whether they are 

 the direct leavings of glaciers or were laid down beneath the sea by 

 floating shore-ice and bergs. Much light will be thrown on this complex 

 problem by endeavouring to ascertain what snow and ice have done in 

 some region which, during the Glacial Epoch, was never submerged, 

 and none better can be found for this purpose than the European Alps. 

 At the present day one school of geologists, which of late years has 

 rapidly increased in number, claims for glaciers a very large share in the 

 sculpture of that chain, asserting that they have not only scooped out 

 the marginal lakes, as Sir A. Eamsay maintained full half a century 

 ago, but have also quarried lofty cliffs, excavated great cirques, and 

 deepened parts of the larger Alpine valleys by something like two 

 thousand feet. The other school, while admitting that a glacier, in 

 special circumstances, may hollow out a tarn or small lake and modify 

 the features of rock scenery, declares that its action is abrasive rather 

 than erosive, and that the sculpture of ridges, crags, and valleys was 

 mainly accomplished in pre-glacial times by running water and the 

 ordinary atmospheric agencies. 



In all controversies, as time goes on, hypotheses are apt to mas- 

 querade as facts, so that I shall endeavour this evening to disentangle 

 the two, and call attention to those which may be safely used in drawing 

 a conclusion. 



In certain mountain regions, especially those where strong lime- 

 stones, granites, and other massive rocks are dominant, the valleys are 

 often trench-like, with precipitous sides, having cirques or corries at 

 their heads, and with rather wide and gently sloping floors, which 

 occasionally descend in steps, the distance between these increasing with 

 that from the watershed. Glaciers have unquestionably occupied many 

 of these valleys, but of late years they have been supposed to have taken 

 a large share in excavating them. In order to appreciate their action 

 we must imagine the glens to be filled up and the district restored to its 

 former condition of a more' or less undulating upland. As the mean 



1 May I add that hereafter a statement of facts without mention of an authority 

 means that I am speaking from personal knowledge ? 



