I>K. J. MORISON — ICE ANT) ITS "WORK. 151 



estimate the tremendous wear and tear to which the surface must 

 be subjected. All the valleys are continually bein<;- deepened ; all 

 the rocks arc being; smoothed, roimded, and striated ; and glacial 

 rubbish — sand, stones, and mud — nu;st exist in great (j^uantity under- 

 neath the ice ; and are constantly being pushed out under the ice 

 into the shallow seas, where they form a sedimentary layer on 

 the sea-bottom, becoming mixed more or less with sea-shells of 

 an Arctic type. 



All around Greenland the sea during winter is covered by a 

 coating of ice from 10 to 20 feet thick. In the early summer, 

 when the ice breaks up, a narrow shelf or platform of ice adheres 

 to the coast. This is called the ice-foot. It breaks up and is 

 carried out to sea towards the end of the summer. During the 

 summer vast piles of rock and rubbish, derived from the waste 

 of the cliffs above, accumulate on the surface of the ice-foot, so that 

 when it finally breaks up, the quantity of rock debris borne out to 

 sea must be very great. Icebergs, also, often carry out to sea 

 large quantities of rock-fragments, and, as they melt slowly and 

 have been found as far south as the Azores, the Arctic debris from 

 Greenland must be scattered far and wide over the floor of the 

 iS^orth Atlantic. Could we suddenly strip Greenland of her mantle 

 of ice and snow, we should find all the hills and mountains rounded, 

 smoothed, polished, and scored up to their very summits, and all 

 the valleys and sheltered places would be covered by a dense clay, 

 full of stones like our boulder-clay. 



Dr. Xansen, who travelled across Greenland in the summer of 

 1888, says that it is so thickly covered by the ice-accumulation 

 of ages, that no part of the interior is ever laid bare. He compares 

 the configuration of the inland ice to a shield curving upwards to 

 a sort of plateau reaching in places at least 10,000 feet above the 

 sea-level. He maintains that the configuration of the ground under- 

 neath must be similar to that of ^N^orway and Scotland, with the 

 same rugged mountain masses, high ridges, valleys, and fiords. 

 The immense accumulation of snow has levelled up everything ; in 

 places the ice must be 6,000 feet deep, and even the mountain tops 

 must be covered by hundreds of feet of glacier. He does not think 

 that the quantity of snow can vary much from year to year. The 

 enonnous pressure of this vast mass of ice and snow pushes out 

 glaciers into the sea, and causes them to send off icebergs. Even 

 in winter Dr. K'ansen maintains that there are running streams 

 of water underneath the ice, due to this pressure, which help 

 to prevent the growth of the mass. 



But it is in the Antarctic regions that we meet with the mightiest 

 accumulation of ice and snow. When Captain Koss undertook 

 his celebrated voyage towards the South Pole, he found his progress 

 southwards barred by a precipitous wall of ice, which rose out of 

 the water for 180 feet. 



For 450 miles Captain Ross sailed in front of this great ice- 

 cliff, and found it unbroken for all that distance by a single gap 

 or inlet. Only at one point was the ice -wall low enough to allow 



