GEOLOGICAL OBSERVATIONS 



tion of movement of this depot, in the six years four 

 months and a half that had elapsed since Captain 

 Scott left it there, the party visited it and Mackin- 

 tosh took a series of angles and measurements, which 

 enabled him to determine that the depot had moved 

 bodily to the east-north-east at the rate of a little over 

 500 yards a year for the past six years and six months. 

 The party also dug down through the hard snow to a 

 depth of 8 ft. 2 in. when they came upon the original 

 snow-surface on which the depot was formed. They were 

 thus able to show that, during the above period, October 1, 

 1902, to February 15, 1909, on the average about 13 in. 

 per year of hard snow had accumulated. In order to 

 determine the density of this snow they melted down a 

 considerable quantity of it, and measured the volume of 

 the thaw-water resulting. This showed that the annual 

 accumulation of snow on this part of the Great Ice Barrier 

 is equal to about 7>4 in. of rain. 



This depot is in the latitude of Minna Bluff, about 

 78° 40' South. Further north, as, for example, in the 

 neighbourhood of Mount Nansen, the snowfall appeared 

 to be considerably heavier, and it seemed to be heavier 

 still nearer to the Antarctic Circle. As in. of rain is 

 equal to7}i ft. of snow it is obvious that the accumulation 

 of snow, even as far south as between latitude 78° and 

 79° is not inconsiderable, but on account of its great 

 density this compressed snow, near Minna Bluff, formed 

 a layer annually 13>4 in. thick, instead of 7>4 ft. thick. 



For the sake of simplicity it may be assumed that the 

 rate of accumulation over the Great Barrier generally 

 is about 1 ft. annually. Now it has been proved that the 

 Great Barrier extends inland for fully 300 miles in places. 

 From the observations at Minna Bluff, and the rate of 

 movement of Captain Scott's Depot A, as measured by 

 Captain Scott and again by Joyce, it may be inferred 



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