part 1] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. V 



ice in the central part of the Southern Continent is of portentous 

 depth, but the speaker saw no evidence to support such a postulate. 

 He regretted that the recent expeditions had not been supplied 

 with boring rods to test the depth. There were other geological 

 issues on which the South Polar region throws much light, and 

 the speaker expressed disappointment that time was not allowed 

 for an adequate discussion of them. 



Dr. J. W. Evans supplemented Prof. Kendall's question by 

 enquiring whether Sir Douglas Mawson could give any idea of the 

 relative importance of melting, evaporation, and wind action in 

 the removal of material from the surface of the ice-cap. 



Mr. Gr. W. Young asked whether the annual banding, so notice- 

 able in the shelf-ice, was analogous to the ' dirt-bands ' of Alpine 

 glaciers (which he thought improbable) or to some physical 

 difference in the ice, the optical appearance of which was accentuated 

 in the photograph. 



Mr. A. E. Kitsox asked, with regard to the islets in Poss Sea, 

 which show very ragged outlines, whether they have had smoothed 

 surfaces such as are usually found on ice-worn rocks, and owe their 

 ragged character to later subaerial erosion ; or have they never 

 "been smoothed by ice ? If the latter, then there seems to be 

 evidence in favour of the su^o-estion that, owins: to the sliding of 

 the ice-sheet over slippery layers in it, there has not been much 

 wearing away of the land-surface. He also enquired whether 

 anything was known as to the relative thicknesses of the ice-shelf 

 and the glaciers that are forcing their way through it. Is there 

 any probability of ascertaining by boring methods the thickness of 

 the less slowly-moving parts of the ice-sheet on the plateau area 

 nearer the Pole ? 



Sir Aubrey Strahan remarked that much of the interest of 

 observations made in Polar regions lay in the light which they threw 

 upon the glacial phenomena of our own country. Of these one of 

 the most conspicuous was the great development of boulder-clays 

 and glacial gravels. He had found, in a limited experience, that 

 such deposits were not so well developed in some northern regions 

 where glaciation had been prolonged and intense, as for example in 

 part of Lapland. He had had, however, an opportunity of 

 observing, in company with the President, an instructive example 

 of recently formed boulder-clay. Ice-tongues, protruding from 

 the inland ice, had invaded some of the bays in Spitsbergen, and 

 the material pushed out by them resembled in every respect a 

 typical British till, including fragments of marine shells or 

 boulders. It was clear that the material had been formed under 

 ice which had invaded the sea, and from under which the escape 

 of mud and water was impeded. It would be interesting to know 

 whether boulder-clay was being formed under the ice-tongues, and 

 especially the ice-shelves, in the Antarctic. 



He expressed his indebtedness to Sir Douglas Mawson for his 

 exposition. It was given to few to have the hardihood to visit 

 such a region, the skill to return from it, and the ability to give 

 so lucid a description of it. 



