192 [Proc. B.N.F.C., 



it were in a bank, and put out to usury ; for the greater the 

 accumulation of ice the more the air is cooled, and the greater 

 the precipitation, and the resulting cloud and fog, as well as 

 the snow and ice, instead of, as in the case of transparent 

 vapour, absorbing the rays of heat, simply reflect them, and, 

 glancing off into space, they are lost for ever. There is, again, 

 what may be termed the alternate theory — viz., that, if not a 

 complete icecap, there was a considerably greater elevation of 

 the land than the present level, with a series of glaciers much 

 larger in extent than any at present known in Europe, and that 

 following this there was a great submergence. Everybody, I 

 think, concedes the fact of a submergence of some sort ; the real 

 question is as to its extent. The chief evidence which has been 

 until recently relied on to prove its extent is a certain stratified 

 bed containing fragrement of sea shells upon Moel Tryfaen, in 

 North Wales, at a height of about 1,300 feet, and a similar bed 

 on the Two Rock Mountain, near Dublin, at about the same 

 height, and beds in Cheshire and Scotland at a somewhat lower 

 level. These were supposed to prove that towards the close of 

 the glacial epoch the British Isles, or all but a small portion in 

 the south, were sunk at least to the greatest of these depths 

 under the sea, and, as Great Britain has since been joined to 

 the Continent, that they were then raised 500 or 600 feet for a 

 few thousand years before they settled back again to their 

 present level. Professor Hull, in a recent paper, seems to take 

 a new view, that along an axis running nearly east and west 

 through Dublin, North Wales, and Cheshire, &c.,the land sunk 

 at least 1,400 feet, and that the sinking became rapidly less as 

 you go farther north and south of that line. An American 

 geologist, who can at least claim the merit of having studied 

 British glaciology as carefully as most English observers, the 

 late Mr. Carvill Lewis, has started some very bold theories, 

 which he backs up, however, with a great deal of both skill and 

 knowledge. He puts aside altogether, except as regards about 

 three or four hundred feet, the idea of a general submergence, 

 and, holding firmly to the belief of a great icecap both in 



