president's address. 27 



British lowlands. That Scandinavia was at one time almost wholly buried 

 beneath snow and ice is indubitable ; it is equally so that at the outset 

 the land stood above its present level, and that during the later stages of 

 the Glacial Epoch parts, at any rate of Southern Norway, had sunk 

 down to a maximum depth of 800 feet. In Germany, however, erratics 

 are scattered over its plain and stranded on the slopes of the Harz and 

 Riesengebirge up to about 1,400 feet above sea-level. The glacial drifts 

 of the lowlands sometimes contain dislodged masses of neighbouring 

 rocks like those at Cromer, and we read of other indications of ice 

 action. I must, however, observe that since the glacial deposits of Moen, 

 Warnemunde, and Rugen often present not only close resemblances to 

 those of our Eastern Counties but also very similar difficulties, it is not 

 permissible to quote the one in support of the other, seeing that the origin 

 of each is equally dubious. Given a sufficient ' head ' of ice in northern 

 regions, It might be possible to transfer the remains of organisms from 

 the bed of the Irish Sea to Moel Tryfaen, Macclesfield, and Gloppa; 

 but at the last-named, if not at the others, we must assume the existence 

 of steadily alternating currents in the lakes in order to explain the 

 corresponding bedding of the deposit. This, however, is not the only 

 difficulty. The ' Irish Sea glacier ' is supposed to have been com- 

 posed of streams from Ireland, South- West Scotland, and the Lake. 

 District, of which the second furnished the dominant contingent; the 

 first-named not producing any direct effect on the western coast of 

 Great Britain, and the third being made to feel its inferiority and 

 ' shouldered in upon the mainland.' But even if this ever happened, 

 ought not the Welsh ice to have joined issue with the invaders 

 a good many miles to the north of its own coast ? x Welsh boulders 

 at any rate are common near the summit of Moel Tryfaen, and I 

 have no hesitation in saying that the pebbles of riebeckite-rock, far 

 from rare in its drifts, come from Mynydd Mawr, hardly half a league 

 to the E.S.E., and not from Ailsa Craig. 2 



As such frequent appeal is made to the superior volume of the ice- 

 sheet which poured from the Northern Hills over the bed of the Irish 

 Sea, I will compare in more detail the ice-producing capacities of the 



1 From Moel Tryfaen to the nearest point of Scotland is well over a hundred 

 miles, and it is a few less than this distance from Gloppa to the Lake District. In 

 order to allow the Irish Sea ice-sheet to reach the top of Moel Tryfaen the glacier 

 productive power of Snowdonia has been minimised (Wright, Man and the Glacial 

 Epoch, pp. 171, 172). But the difference between that and the Arenig region is not 

 great enough to make the one incompetent to protect its own borderland while the 

 other could send an ice-sheet which could almost cover the Clent Hills and reach the 

 neighbourhood of Birmingham. Anglesey also, if we suppose a slight elevation and a 

 temperature of 29° at the sea-level, would become a centre of ice-distribution and an 

 advance guard to North Wales. 



2 The boulders of picrite near Porth Nobla, from Llanerchymedd, though they 

 have travelled southward, have moved away much to the west. 



