September 1G, 1910] 



SCIENCE 



355 



from Upernivik. But since the difference 

 at the present day between Cape Farewell 

 and Christiania (the one in an abnormally 

 cold region, the other in one correspond- 

 ingly warm) is only 7°, that allowance 

 seems much too large, while without it 

 Scandinavia would correspond in tempera- 

 ture with some part of that country from 

 south of Upernivik to north of Frederik- 

 shaab.^" But if Christiania were not colder 

 than Jakobshavn is now, or Britain than 

 Spitzbergen, we are precluded from com- 

 parisons with the coasts of Baffin Bay or 

 Victoria Land. 



Thus the ice-sheet from Scandinavia 

 would probably be much greater than those 

 generated in Britain. It would, however, 

 find an obstacle to progress westwards, 

 which can not be ignored. If the bed of 

 the North Sea became dry land, owing to 

 a general rise of 600 feet, that would still 

 be separated from Norway by a deep chan- 

 nel, extending from the Christiania Fjord 

 round the coast northward. Even then 

 this would be everywhere more than an- 

 other 600 feet deep, and almost as wide as 

 the Strait of Dover. ^^ The ice must cross 

 this and afterwards be forced for more 

 than 300 miles up a slope, which, though 

 gentle, would be in vertical height at least 

 600 feet. The task, if accomplished by 

 thrust from behind, would be a heavy one, 

 and, so far as I know, without a parallel 

 at the present day; if the viscosity of the 

 ice enabled it to flow, as has lately been 

 iu"ged,*^ we must be cautious in appealing 

 to the great Antarctic barrier, because we 

 now learn that more than half of it is only 

 consolidated snow.'*" Moreover, if the ice ■ 



"Christiania and Cape Farewell (Greenland) 

 are nearly on the same latitude. 



" For details see Geol. Mag., 1899, pp. 97 and 

 282. 



« H. M. Deeley, Geol. Mag., 1909, p. 239. 



" E. Shackleton, " The Heart of the Antarctic," 

 II., 277. 



floated across that channel, the thickness 

 of the boulder-bearing layers would be 

 diminished by melting (as in Ross's Bar- 

 rier), and the more viscous the material, 

 the greater the tendency for these to be left 

 behind by the overflow of the cleaner upper 

 layers. If, however, the whole region be- 

 came dry land, the Scandinavian glaciers 

 would descend into a broad valley, consid- 

 erably more than 1,200 feet deep, which 

 would afford them an easy path to the 

 Arctic Ocean, so that only a lateral over- 

 flow, inconsiderable in volume, could spread 

 itself over the western plateau.^^ An at- 

 tempt to escape this difficulty has been 

 made by assuming the existence of an inde- 

 pendent center of distribution for ice and 

 boulders near the middle of the North Sea 

 bed^"* (which would demand rather excep- 

 tional conditions of temperature and pre- 

 cipitation) ; but in such case either the 

 Scandinavian ice would be fended off from 

 England, or the boulders, prior to its ad- 

 vance, must have been dropped by floating 

 ice on the neighboring sea-floor. 



If, then, our own country were but little 

 better than Spitzbergen as a producer of 

 ice, and Scandinavia only surpassed south- 

 ern Greenland in having a rather heavier 

 snowfall, what interpretation may we give 

 to the glacial phenomena of Britain? 

 Three have been proposed. One asserts 

 that throughout the glacial epoch the Brit- 

 ish Isles generally stood at a higher level, 

 so that the ice which almost buried them 

 flowed out on to the beds of the North and 

 Irish Seas. The boulder clays represent its 



"It has indeed been affirmed (Briigger, " Om 

 de senglaciale og postglaciale nivaforandringer i 

 Kristianiafelted, p. 682) that at the time of the 

 great ice-sheet of Europe the sea-bottom must 

 have been uplifted at least 8,500 feet higher than 

 at present. This may be a ready explanation of 

 the occurrence of certain dead shells in deep 

 water, but, unless extremely local, it would revolu- 

 tionize the drainage system of central Europe. 



" Geol. Mag., 1901, pp. 142, 187, 284, 332. 



