Correspondence — R. M. Deeley. 87 



Eoss and Scott, A-aries from 1,500 to 2,700 feet. If the submerged 

 ice is six times the thickness of the portion above the sea-level, the 

 depth of the barrier in the sea must vary from 300 to 1,440 feet. 

 There is, therefore, in many places more than 1,000 feet of water 

 between the sea-bottom, for the thin ice is frequently above the deep 

 water. The ice of the barrier, except at its ends, is floating along its 

 whole front. On this matter Sir James Ross says : " Whilst waiting 

 we obtained soundings in two hundred and thirty fathoms, the deep 

 sea clamms bringing up some green mud intermixed with small 

 volcanic stones. This depth of water would seem to prove that 

 the outer edge of the barrier was not resting upon the ground ; for 

 by various measurements of its highest part it was found to be one 

 hundred and seven feet above the sea, from which point it gradually 

 diminished for about ten miles to the eastward, where it could not 

 have been more than eighty feet." Here there was, therefore, about 

 1,100 feet of water under the ice. Captain Scott found that the edge 

 of the ice when he sailed along it was about 30 miles further south 

 and the sea quite as deep. The statement made by Koss that the 

 barrier was floating must, consequently, have been quite correct. At 

 Balcon Inlet, near the eastern edge of the barrier, Captain Scott 

 noticed that a small " berg, as well as the pack ice which had been 

 driven in by the current, took its way out to sea again, clearly 

 showing that there is a regular tidal stream in this region, and as, 

 in spite of this, we and the barrier ice about us rose and fell together, 

 there was no doubt that at least this part of the barrier was afloat". 



But Scott travelled south over the barrier ice until he was about 

 300 miles from its face, and his observations showed that he had 

 travelled over a comparatively level plain all the way, the ice being of 

 nearly uniform thickness, his opinion being that the " Great Barrier 

 ice-sheet is afloat at least as far south as we travelled ". He also 

 remarks: "I still hold that the greater part of it is afloat; and 

 strange as it is to imagine that the sea should run beneath such a solid 

 sheet for so many hundreds of miles, I have yet to learn any reasonable 

 argumeut aguiust such an idea." I am here in complete accord with 

 Captain Scott, and think that his reasoning is quite unanswerable. 

 Ice behaves as a very viscous liquid, and may rest upon and slowly 

 spread over water, a tendency to spread lesulting from the fact that 

 a portion of it stands above the sea-level. 



As it is possible for an ice-sheet such as that which Boss and Scott 

 described to maintain itself when exposed to the open Pacific, it is 

 also possible for a similar ice-sheet to maintain itself in the North Sea 

 during a glacial epoch, this sea facing the cold north instead of the 

 open warm sea. 



It is argued without any clear reason being given that an ice-sheet 

 could not cross the deep channel near the Scandinavian Peninsula. 

 I do not think that this is a real difiiculty. In the first place, the 

 moderately thick ice lobes would float across the channel, and Avhen 

 they touched the sea-bottom on the opposite side the ice over the 

 channel would thicken. This thickening and consequent rise above 

 the sea-level would furnish the necessary gradient to force the ice 

 towards Great Britain. The distance the ice would travel would 



