288 CAINOZOIC PAL.EOGEOGRAPHY 



glaciated and grooved by an ice-sheet coming from the west, apparently an overflow 

 from the David Glacier towards the E.N.E. In fact the whole of the coast-liue 

 from Cape Irizar for about 12 miles south, which now rises from GOO to 800 feet 

 above the sea, is probably an island, Lamplugh Island, the whole of which has 

 recently been enveloped in the glacier ice of the outlet glaciers and piedmont 

 glaciers. Prior Island, between Cape Irizar and the Cheetham Ice Barrier Tongue, 

 about 300 feet high, has also obviously been over-ridden by glacier ice. It may be 

 added that Cape Irizar is strewn with a great variety of erratics. 



Next, the formation of the terraces to the north and south of the Mawson 

 Glacier show that the ice of that glacier has formerly occupied the greater part of 

 the upper terrace which lies at an altitude of 700 to 1000 feet above the surface of 

 the present glacier. Depot Island, and the adjacent coast-line near Cape Ross, were 

 also found to have been powerfully glaciated. Depot Island is about 200 feet above 

 sea-level. At Granite Harbour, the Mackay Glacier, like the Mawson Glacier, lies 

 in a well-marked, over-deepened valley. (See Plate XVI. of Chapter IV.) A wide 

 upper valley, or alb valley, excavated during the ice flood,* is now from 700 to 1000 

 feet above the level of the adjacent glacier. Dunlop Island, which is now quite ice- 

 free, rises to a little over 100 feet above sea-level. The hills on either side of the 

 Ferrar Glacier, botli in North Fork and East Fork, show evidence of having been 

 formerly intensely glaciated up to heights of from 2000 to 3000 feet above the level 

 of the present glacier. 



The grandest and most convincing evidence of this kind aff'orded by any feature 

 as yet known in the whole of the Antarctic regions is that supplied by the glaciated 

 surfaces and wonderful moraine deposits around the western, southern, and eastern 

 sides of Ross Island. These remarkable moraines, containing an assortment of nearly 

 all the rocks, except those of very soft and friable nature, which are to be found on 

 the mainland to the south and west, attain an altitude of a little over 1000 feet 

 above sea-level to the east of Cape Royds on the foothills of Erebus, while on the 

 south-eastern slopes of Mount Terror, as already stated, they reach an altitude of 

 about 240 metres above the level of the adjacent glacier ice. It is most fortunate 

 that such a magnificent gauge of the former height of the Ross Barrier as Ross 

 Island already existed at the time of maximum glaciatlon. It is interesting to note 

 that, in the glaciation of the Cape Royds region, in spite of the powerful thrust from 

 the west of the ice of the Ferrar Glacier, the ice of the Ross Barrier was able to keep 

 direct on its northerly course without showing the influence of this north-easterly 

 component of ice movement. This persistent northerly movement of the former Ross 

 Barrier past Cape Royds is perhaps due in part to the protection afforded by the 

 high massif of the Royal Society Range lying to the south-west. 



* It is still doubtful how far this upper wide valley has been formed by "ice flood" glaciers, and 

 how far they have been formed and modified by ciique glaciers. We consider that they are mostly 

 of ice flood origin. 



