PREHISTORIC WORLD.

Otago Daily Times, Issue 20323, 3 February 1928, Page 12

PREHISTORIC WORLD.

FLOATING CONTINENTS. SIR EDGEWORTH DAVID’S LECTURE. (Feom Ope Own Coeeespondent.) SYDNEY, January 26. One of the outstanding personalities at the annual congress at Hobart of the Association for the Advancement of Science was Professor Sir Edgeworth David, of Sydney. One of Nature’s gentleman, he charms all who come in contact with him. His facility for interesting the public in scientific matters is remarkable, so it is not surprising that when Re gave a public lecture at Hobart on the subject " Do Continents Float? ” he had a large and interested audience. Professor David said that radio-active evidence showed that some of the oldest rocks dated back 1,600,000,000 years. In such a vast period of time the continents had moved both vertically and horizontally. For example, the recent work of geologists in New Guinea had shown that deposits of shell material ..übmerged under the sea at no very remote-geo-logical age had now been elevated 16,000 ft above sea level, and constituted the high mountain range like that in which .» situated Queen Wilhelmina Peak, near the centre of the island.

Recent work by the distinguished Swiss geologist, Wegner, had shown, said Sir Edgeworth David, * that the earth’s crust in that region had actually moved horizintally in a south to north direction, estimated at from 350 to 700 miles. So great a movement as this was considered to have carried what was formerly the north shore of Africa, between Algiers and Tunis, right across what is now the Mediterranean, crumpling the rock material up so as to form what was now the highest of the Swiss Alps. This astounding conclusion, now widely accepted, was based on the fact that the Swiss Alps were built up put of immense folds or pleats of the earth’s crust. As a result of their foundations being temporarily dissolved, the continents began to move under the influence of tidal and other forces, and as the tides moved from east to west, the tendency was to puil the continents apart in north and south directions, and drag the western portion of such a rifted region westwards. The Swiss geologist showed that the Americas had thus drifted apart from Africa and Western Europe, the result being the genesis of the Atlantic Ocean. Near about the late carboniferous time all these countries were united in a single mass, said the lecturer. Indeed, the world consisted 'of a single great lano mass. Australia at that time was attached to the eastern side of India and Ceylon, along what is now its west coast. The great Australian Bight and the southern coast generally were attached to that part of the Antarctic which comprised the region of Adelie Land, latelv explored by Sir Douglas Mawson, while Tasmania and the submerged areas to the south were joined on to the portion of Antarctic. where is now the large gulf of Ross Sea.