iv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [vol. lxx\% 



DlSCUSSIOX. 



The President (Mr. G. W. Lampllgh) conveyed the thanks, 

 of the Society to Sir Douglas Mawson for his luminous description 

 of Antarctic conditions, and for his selection of the magnificent 

 illustrative photographs on this as well as on a former occasion. 

 The fact that the explorer was in this case a thoroughly competent 

 geologist Avas indeed fortunate. The Fellows had been thus enabled 

 to participate without effort in the new knowledge gained through 

 heroic labour by the lecturer and his comrades. A further privilege 

 was afforded to the Glacial geologists present by Sir Douglas 

 Mawson's readiness to impart the information that he, more than 

 any other man, possessed, and, as time was limited, the President 

 hoped that the speakers would take advantage of this privilege 

 rather than give expression to their particular views. 



For his own part, he would like to ask at once whether Sir 

 Douglas had formed any opinion as to the origin of the evidently 

 bold land-features that were buried under the ice — could they have 

 been carved out by the ice itself, or were they the relics of a time 

 when the land was ice-free ? 



Prof. P. F. Kendall enquired how much wastage of the Ant- 

 arctic ice was due to melting ? This had been an important factor 

 during the disappearance of the British ice-sheets, but was appa- 

 rently unimportant under present conditions in the Antarctic. 



Sir Henry Howorth, after a general statement of the differ- 

 ences between the glacial phenomena in the Arctic and those in the 

 Antarctic, said that it had been formerly believed that the greater 

 part of the Southern Continent was a vast, low-lying, more or less 

 flat surface covered with a dome-shaped ice-cap. This was Croll's 

 view, and an important element in his presentation of the Glacial 

 theory which he insisted upon in a polemic with the speaker. But 

 it was now evident that, instead of being a- low plain, this continent 

 is a congeries of high lands partly masked by a mantle of ice 

 and snow, resembling Greenland, whence true glaciers flow radi- 

 ally from a large Mer de Glace probably consisting of embayed 

 ice. Such a land is fundamentally different from a polar ice-cap,, 

 as understood by Agassiz and Croll and other inventors and pro- 

 pagators of the Glacial Xightmare. The speaker maintained that 

 ice cannot move unless under the influence of gravity on a slope 

 of sufficient gradient, and if the slope ceases it can only move 

 when pushed by ice coining down the slope behind. Croll's hypo- 

 thesis needed a huge mound of ice with a sufficient sloping top to 

 enable the layers of ice to move over each other in lieu of the 

 sloping bed; hence his view as to an Antarctic ice-cap. But such 

 a mass could not exist, since the modulus or crushing strain under 

 which ice gives way only admits of a very moderate piling-up of 

 an ice-cap. This makes it impossible and not merely improbable 

 that, for instance, the postulated Scandinavian ice-sheet could 

 carry boulders to England and the Carpathians across hundreds of 

 miles of level plains. Sir Douglas Mawson had suggested that the 



