THE HEART OF THE ANTARCTIC 



due to strong rushes of cold air from the high plateau 

 down the broad valley occupied by the Mount Nansen 

 glacier. That day we passed over a series of pressure 

 ridges with their steeper sides directed towards the 

 north-west. At the bottom of these steep slopes the 

 ice was often crevassed, and sometimes we had some little 

 difficulty in crossing them. They were probably due to 

 pressure from the Drygalski Glacier. 



At lunch time, soon after midnight, we reached 

 some very interesting glacial moraines in the form 

 of large to small blocks, mostly of eruptive rock, em- 

 bedded in the ice. It was probable, from their general 

 distribution, that they formed part of an old moraine 

 of Mount Nansen, though now about fifteen miles in 

 advance of the present glacier front. A conspicuous 

 rock amongst the boulders was a greenish-grey to green- 

 ish-black diorite, very rich in sphene. The brown crystals 

 of sphene were frequently intercrystallised with the 

 felspars, and gave the rock a very pretty appearance. 

 Small fragments of sandstone and clay shale were also 

 represented in these moraines. The larger blocks were 

 up to seven feet in diameter, and formed chiefly of 

 reddish porphyritic granite. We collected a number 

 of specimens from this moraine. 



Fine rolls of cumulus clouds were gathering to our 

 north-east. The day was calm with occasional gleams 

 of sunshine. After the plateau wind had died down 

 about 2 P.M. it commenced to snow a httle, the snow 

 coming from between south-west and west-south-west. 



At midnight on December 19 we started sledging 

 in the falling snow, guided partly by the direction of 

 the wind, partly by that of the pressure ridges and 

 crevasses, occasionally taking compass bearings. Before 

 we had gone far we reached a tide-crack with open 

 water three to four feet wide. There was also a width 



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