LONDON. Geological Society, June 19.—Mr. G. W. Lamplugh, president, in the chair.—Sir Douglas Mawson: Some features of the Antarctic ice-cap. The ice-mantle of the south formerly involved the sub-Antarctic Islands, Patagonia, southern New Zealand, and the higher mountains of Tasmania and of the neighbouring portions of Australia, but it retreated to its present confines—a circumpolar continent—at a time apparently concurrent with the disappearance of the extensive Pleistocene ice-sheets of the northern hemisphere. The existence of a great land mass situated on the face of the globe just where the sun's rays fall most obliquely has the effect of intensifying the polar conditions. This result is achieved by reason of the elimination of the ameliorating influence of the ocean and as a result of the acceleration of the circulation of the moist atmosphere from the surrounding sea to the land, owing to the wide difference in temperature pertaining over the one and the other. Thus the presence of extensive land at the Pole, in contradistinction to ocean, results, under present cosmical conditions, in increased refrigeration, and consequently in greater extension of the polar ice-cap. This, in turn, reflects on the average temperature of other regions of the globe, for an ice surface absorbs but a relatively small proportion of the sun's radiant heat. The existence of the Antarctic continent must therefore have some bearing on the climate of the northern hemisphere, and be reckoned with as a factor contributing to the refrigeration thereof. The shelf-ice formations, including the Ross Barrier and the Shackleton Shelf, were specially referred to; mention was made of their growth and decline, of a method of determining their depth below water, and of the probability of specialised life existing beneath such formations.