Vice-President's Address. 189 



conditions of the Quaternary period. These, however, are 

 now so well known, that I need do no more than remind you 

 that, so far as the chief features of our lands are considered, 

 all these had come into existence before the dawn of the Ice 

 Age. The greater contours of the surface, which were fore- 

 shadowed in PaUeozoic times, and wliich in Mesozoic times 

 were more clearly indicated, had been fully evolved by the 

 close of the Pliocene period. The connection between the 

 Mediterranean and the Indian Ocean probably ceased in late 

 Pliocene times. The most remarkable geographical changes 

 which have taken place since then within European regions 

 have been successive elevations and depressions, in conse- 

 quence of which the area of our continent has been alternately 

 increased and diminished. At a time well within the human 

 period, our own islands have been united to themselves and 

 the continent, and the dry land has extended north-west and 

 north, so as to include Spitzbergen, the Faroe Islands, and 

 perhaps Iceland. On the other hand, our islands have been 

 within a recent period largely submerged. Similarly, in. 

 North America, we are furnished with many proofs of like 

 oscillations of level having taken place in Quaternary times. 

 Is it possible, then, to explain the climatic vicissitudes of the 

 Pleistocene period by means of such oscillations ? Many 

 geologists have tried to do so, but all these attempts have 

 failed. It is quite true that a general elevation of the land 

 in high latitudes would greatly increase the ice-fields of Arctic 

 regions, and might even give rise to perennial snow and 

 o'laciers in the mountain-districts of our islands. But it is 

 inconceivable that any such geographical change could have 

 brought about that general lowering of temperature over the 

 whole northern hemisphere which took place in Pleistocene 

 times. Por we have to account not only for the excessive 

 glaciation of northern and north-western Europe, and of the 

 northern parts of North America, but for the appearance of 

 snow-fields and glaciers in much more southern latitudes, 

 and in many parts of Asia where no perennial snow now 

 exists. Moreover, w^e have to remember that Arctic condi- 

 tions of climate obtained in north-western Europe even when 

 the land was relatively much lower than it is at present. 



