44 GEOLOGICAL NOTES ON KOSCIUSKO, 



this valley must have attained a thickness of at least 500 feet. 

 As, however, the top of the ridge itself has evidently been 

 heavily glaciated, this implies that the ice on top of this ridge 

 must have been probably not much less than 100 feet in thickness. 



If this were so, as seems most probable, the ice would have been 

 600 feet thick in the Lake Albina Valley, and its surface close 

 upon 6,950 feet above the sea. As already mentioned the bases 

 of the Nunatakr of the Etheridge Range are about 6,908 feet 

 high. Now interesting conclusions necessarily follow from this. 

 As Townsend's Pass is only 6,650 feet high, part of the Snowy 

 Valley glacier may have come over the top of Townsend's Pass, 

 the ice at the Pass being perhaps at one time 200 feet or even 

 300 feet thick. Similarly at Adams' Pass (between the Snowy 

 Valley and the Wilkinson Valley), the level of which is only 

 about 6,587 feet, the ice must have escaped from the Snowy 

 Valley ice sheet into the Wilkinson Valley below in masses 

 which, at Adams' Pass, were probably at least 250 feet, perhaps 

 350 feet or more in thickncwss. 



An interesting problem now suggests itself in connection with 

 the glaciation of this ridge between the head of the Wilkinson 

 Valley and Lake Albina, viz.: in what direction did the ice 

 move which so powerfully glaciated the western granite slopes 

 of the Lake Albina Valley up to the top of the ridge? The 

 mean trend of the grooves on the seven glaciated surfaces 

 specially observed is E. 17^ N. and W. 17° S. Now did the ice 

 move from the east end or from the west end ? If from the west, 

 it must probably have been supplied by the overflow from the Mt. 

 Townsend glacier, which may have overpowered the western part 

 of the ice coming over Townsend's Pass from the Snowj'- Valley 

 glacier. If it moved from the east, it probably was derived from 

 the Snowy Valley glacier, extended via Townsend's Pass into the 

 Lake Albina Valley, and overflowing the dividing ridge between 

 Lake Albina and the Wilkinson Valley, so as to reinforce the 

 Wilkinson Valley glacier. The carry of the material in the 

 moraine of the Lake Albina Valley suggests a westerly move- 

 ment of the ice, as while the junction line between the granite 



