THE HEART OF THE ANTARCTIC 



One other testimony to the power of the plateau wind 

 as a denuding agent was well shown at a height of 6000 

 ft. on the Terracotta Mountain, where the talus became 

 sufficiently thin for the Beacon sandstone to be seen in 

 situ. One of the beds of sandstone was a fine grained 

 white rock and this stood out in ledges eighteen or twenty 

 inches wide, and the underside of these ledges had been 

 weathered into a series of thin, roughly hexagonal columns 

 from one to nine inches long, and from a quarter to half 

 an inch thick. 



Where these columns hung close together their original 

 structure seemed, as before mentioned, to be hexagonal, 

 and it appears probable that the weathering has been 

 assisted in producing this particular type by some 

 secondary structure due to alteration and secondary 

 crystallisation in the rock itself. When the columns hung 

 further apart, owing to the gaps made by the entire 

 removal of some, they had lost all definite shape and 

 resembled nothing so much as stone icicles. Several 

 specimens of both types of weathered sandstone were 

 collected, but those of the latter type were extremely 

 difficult to preserve during a sledge journey over rough 

 ice, and one or two also were damaged in the transition 

 from the Butter Point Depot to the ship. 



On the way down the glacier any specimens were col- 

 lected which had peculiar markings on them, and these 

 and the other specimens secured will be carefully examined 

 when the detailed petrological work is done, but it is very 

 improbable that any of them will reveal the presence of 

 any organic remains sufficiently unaltered to be 

 identifiable. 



At the entrance of the east fork of the glacier and on 

 the north side we passed and examined moraines which 

 were essentially different from the ordinary moraines met 

 with higher up, and there seems no doubt that the sea 



340 



