THE HEART OE THE ANTARCTIC 



that the Great Barrier there is travelhng seawards at the 

 rate of about one-third of a mile per year. From this it 

 may be argued that a snowfall on any part of the Barrier 

 300 miles inland would take 900 years to reach the edge 

 of the Great Ice Barrier, where bergs are discharged into 

 the sea. At this rate, if 1 ft. of snow is added to the 

 Barrier every year a layer of snow, formed 300 miles 

 inland, 900 years ago, if it reaches the Great Barrier cliffs 

 at the present day will be covered by a thickness of 900 ft. 

 of snow. Obviously this theory gives a vast thickness of 

 snow to form the seaward end of the Great Barrier. 

 Theoretically then as the result of the calculations from 

 the observations of the southern depot party, it might 

 be argued that a considerable thickness of the berg 

 material derived from the Great Ice Barrier was formed 

 of consolidated snow and neve rather than of true glacier 

 ice. Practical proof of this was afforded us by another 

 series of observations. At the end of the breaking up of 

 the sea ice in the summer of 1907-8, three bergs drifted 

 into McJMurdo Sound, and grounded between our winter 

 quarters and Cape Barne. During the following winter 

 the sea was frozen over around these bergs, and we were 

 able to go over to them and study them. Fortunately 

 they were much tunnelled by sea- worn caves. This en- 

 abled us to see their internal structure. We found that 

 all around the edge, particularly along the line of the 

 wave-worn groove which surrounds all bergs, a good deal 

 of ice was developed. This ice resulted evidently from 

 the freezing of sea water as the waves washed and dashed 

 against the foot of the berg cliff. In heavy weather a 

 large quantity of spray would be flung high up against 

 the cliff faces of the berg, and the spray freezing would 

 encrust the exterior of the berg with ice. There was no 

 evidence, however, of the existence of any solid ice inside 



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