ANNIVERSARY ADDRESS OF THE PRESIDENT. xllii 



calities, so far as they have been previously observed, have usually 

 been regarded as moraines ; but Professor Ramsay considers, and it 

 appears to me with great reason, that the continuity of the whole 

 accumulated mass with the shell-bearing portions of it constitutes a 

 strong argument in favour of its entire submarine origin. This view 

 appears also to be confirmed by the existence of large blocks, which 

 have travelled considerable distances, now resting on the tops or sides 

 of mountains, as above stated, at the altitude of 2000 feet. We shall 

 most of us probably agree entirely with the author in the validity of 

 this reasoning. 



Professor Ramsay also recognizes moraines at considerable, eleva- 

 tions above the sea, but much lower than the greatest height to 

 which the Drift attains. Coupling this fact with the conclusion of 

 the preceding paragraph, he expresses his belief that there must 

 have been two glacial epochs in this region, the first preceding the 

 deposition of the Drift ; the second, posterior to that deposition, pro- 

 ducing glaciers on a much smaller scale. " For," says the author, "if 

 the loose moraines of Cwm Idwal" (which he has previously described) 

 " had been formed during i\iQ great glacier period, they would either, 

 in all probability, have been destroyed during the depression and re- 

 elevation of the land which followed that period, or they would have 

 been covered over and smothered in the succeeding drift." 



This reasoniug will not perhaps be deemed equally satisfactory 

 with that by which the author establishes his conclusion respecting 

 the depth to which the land of this region was submerged during the 

 period of the Drift ; but I am still disposed to think his conclusion 

 to be so far correct, that these moraines (assuming them to be such) 

 were formed after the re-elevation of the land from its lowest position 

 of submergence. I cannot, however, agree with the author in ad- 

 mitting the evidence of two distinct glacier-periods. He would 

 ascribe the glaciers of his first period to an enormous elevation of the 

 whole region, and those of his second period to some peculiar con- 

 ditions after the intervening submergence. I must of course feel 

 myself bound, in consistency with what I have recently brought before 

 you on the possible causes of changes of climatal conditions, to express 

 my dissent from any theory that should assign a great elevation to 

 Western Europe as an essential condition for the former existence of 

 glaciers there. Their existence in Wales, both before and after the 

 actual transport of those accumulations properly termed Drift, is just 

 as well accounted for independently of any great upheaval of this 

 region, and withoiii: the hypothesis of a discontinuity in the glacier- 

 period. We have only to suppose glaciers to have first resulted from 

 the cold caused by the diversion of the Gulf-stream into some other 

 channel, and the submergence of a great portion of Europe ; then a 

 deeper submergence which left not more perhaps than one-third of 

 Snowdon extant above the waters ; and finally an emergence of the 

 land to an elevation which should allow of glaciers descending to the 

 points where the above-mentioned moraines are now observed. The 

 depression of the land might be such as to bring the tops of the par- 

 ticular mountains we are now speaking of below the snow-line, and 



