Islands, and probably even Greenland, were once connected 

 with Europe, at a time, when now living species were in exi- 

 stence, and that this supposed land-bridge offers, possibly, an ex 

 planation of the great Ice Age in the countries surrounding the 

 North Atlantic Ocean. 1 The Pliocene Red Crag of England 

 has 92 per cent of living species of Mollusca. If we suppose that 

 the land-bridge was upheaved above the sea level in Pliocene 

 times, then we have an explanation of the similarity in the 

 fauna and flora on both sides of the North Atlantic and in the 

 above-named islands, as well as of the Ice Age. And when 

 the land-bridge was submerged, the warm current again got 

 access to the North Atlantic and the glaciers retired. But a 

 great mer de glace cannot melt in a short time. The warmth of the 

 sun is consumed in melting ice and snow. As long as the coun- 

 try is snow-clad the temperature will remain low. And the pre- 

 cipitation in the icy land will fall to a great extent as snow. 

 The effect on climate of a great inland ice thus tends to the 

 preservation of the glacial state. It is probable that glacial 

 conditions will last for a long time after the submergence of 

 the land-bridge. 



If, now, similar changes have taken place at the Behring Sea 

 and Strait, if, for instance, the Pacific once corresponded more freely 

 with the Polar sea; a warm current would perhaps flow from the 

 Pacific to wash the shores of the Arctic islands north of America. 

 And who knows whether such, or similar geographical changes of small 

 extent, might not be sufficient to explain, how Ginkgo, Taxodiuffl, 

 Sequoia, Fagus, Castanea, Platanus, Iuglans, Hedera and the 

 like, once flourished in Grinnell Land and on Hare Island. 



The old marine terraces and raised beaches show, that 

 arctic North America was upheaved to a considerable extent id 

 Post-Tertiary times. Drift timber and marine shells occur *t 

 very considerable heights in many places in these northern 



