30 president's address. 



be prevalent ; though changes of wind l would often affect the drift 

 of the floating ice-rafts. But though the submergence hypothesis is 

 obviously free from the serious difficulties which have been indicated 

 in discussing the other one, gives a simple explanation of the presence 

 of marine organisms, and accords with what can be proved to have 

 occurred in Norway, Waigatz Island, Novaia Zemlya, on the Lower 

 St. Lawrence, in Grinnell Land, and elsewhere, 2 it undoubtedly in- 

 volves others. One of them — the absence of shore terraces, caves, or 

 other sea marks — is perhaps hardly so grave as it is often thought 

 to be. It may be met by the remark that unless the Glacial Age 

 lasted for a very long time and the movements were interrupted by 

 well-marked pauses, we could not expect to find any such record. In 

 regard also to another objection, the rather rare and sporadic occur- 

 rence of marine shells, the answer would be that, on the Norway coast, 

 where the ice-worn rock has certainly been submerged, sea-shells are 

 far from common and occur sporadically in the raised deltaic deposits 

 of the fjords. 5 An advocate of this view might also complain, not 

 without justice, that, if he cited an inland terrace, it was promptly dis- 

 missed as the product of an ice-dammed lake, and his frequent instances 

 of marine shells in stratified drifts were declared to have been trans- 

 ported from the sea by the lobe of an ice-sheet; even if they have 

 been carried across the path of the Arenig ice, more than forty miles, 

 as the crow flies, from the Irish Sea up the Valley of the Severn, or 

 forced some 1,300 feet up Moel Tryfaen.* The difficulty in the latter 

 case, he would observe, is not met by saying the ice-sheet would be 

 able to climb that hill ' given there were a sufficient head behind 

 it. ' 5 That ice can be driven uphill has long been known, but the 

 existence of the ' sufficient head ' must be demonstrated, not assumed. 

 There may be ' no logical halting-place between an uplift of ten or 

 twenty feet to surmount a roche moutonnie and an equally gradual 



1 See p. 25, and for the currents now dominant consult Dr. H. Bassott in Professor 

 Herdman's Report on the Lancashire Sea Fisheries, Trans. Biol. Soc. Liverpool, xxiv. 

 (1910), p. 123. 



2 See Ice Work, p. 221, and Geol. Mag., 1900, p. 289. 



3 If, as seems probable, the temperature was changing rather rapidly the old 

 fauna would be pauperised and the new one make its way but slowly into the British 

 fjords. 



4 Critics of the submergence hypothesis seem to find a difficulty in admitting 

 downward and upward movements, amounting sometimes to nearly 1,400 feet 

 during Pleistocene Ages ; but in the northern part of America the upheaval, at any 

 rate, has amounted to about 1,000 feet, while on the western coast, beneath the 

 lofty summit of Mount St. Elias, marine shells of existing species have been obtained 

 some 5,000 feet above sea-level. It is also admitted that in several places the pre- 

 glacial surface of the land was much above its present level. On the Red River, 

 whatever be theexplanation, foraminifers, radiolarians, and sponge spicules have been 

 found at 700 feet above sea-level, and near Victoria, on the Saskatchewan, even up 

 to about 1,900 feet. 



6 P. F. Kendall in Wright's Man and the Glacial Period, p. 171. 



