GLACIERS AND ICEBERGS. 
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hanging valleys all hang about 300 feet above the ice of the main valley, and 
therefore at about 2000 feet above sea-level. In some of them the hanging lip is very 
evident, while in others the Thalweg is very nearly uniform all the way. 
8. Hanging Glaciers ; Corrie-glaciers (Fig. 20, p. 42). 
Four Corrie-glaciers are worthy of mention. These lie on the south side of 
the Inland Forts and occupy the cirques below the cols which link up the Forts. 
Three of these glaciers are quite isolated, but the fourth is joined by a tributary 
from the west side of Round Mountain (Cj). All flow southwards, but fail to reach 
the ice of the main valley, and are now building up crescentic moraines at their 
terminations. The interest of these glaciers lies in the fact that, though they now 
flow southward, they were formerly forced northward by the Ferrar Glacier into 
another drainage-system. Their supply is local from the Inland Forts, and the cols 
at their heads are completely bare. 
9. Ice-slabs (Plate VI). 
Ice-slabs are found in all valleys on the east side of the Southern Foothills 
of the Royal Society Range. These slabs are masses of ice, four to six square miles 
in extent and about 50 feet thick. They are the relics of glaciers which once 
drained the Snow Valley ; but, owing to diminution of ice-supply, this has now 
become an inland basin, and its overflows have slipped away from it, leaving a 
subsidiary watershed bare. The surface of the ice- slabs is quite clean, and free 
from mud or stones. It is convex and slopes gently outwards from a centre. The 
ice-cliffs which bound ice-slabs show abundant dirt-bands and scattered morainic 
matter in their lower parts. In each valley in the Southern Foothills there is a 
glacier of this type, and it would seem that their development is due to the peculiar 
forms of the hills and their surroundings. 
O 
10. Icebergs (Fig. 40). 
Icebergs have been defined by Heim as masses of glacier-ice floating in the 
sea. They are common to both polar regions. The icebergs of South Victoria 
Land are usually tabular in form, and the vast majority seem to be derived from 
some common source. Shore-ice is not prolific in the formation of bergs, as such 
ice remains firmly fixed to the land throughout the year. Blue Glacier was under 
observation for over sixteen months, and during that time no berg broke away 
from it, the snout remaining firmly frozen on to the sea-ice from the year 1902 
to the year 1904. Within a mile of Blue Glacier, however, five bergs were aground, 
and could only have been derived from it. 
VOL. I. 
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