SPHimrr, Cockaynf^ LAixr;. — Momif ArroirxniifJi Dfsfricf. 327 



recent origin, cut for about three miles through a solid rock barrier, the 

 height of the lip above the floor of the basin on its up-stream side being 

 over 200 ft.. It is extremely likely that a lake once occupied this basin, 

 which has been drained by the river cutting down its bed through the solid 

 obstruction. It seems impossible to explain the peculiar relation of basin 

 and barrier on any other assumption than that large valley glaciers have 

 under certain circumstances great powers of basal excavation. No locality 

 that I am acquainted with shows this better. 



Immediately outside this ice-eroded basin the moderately elevated 

 country has been dissected and the drainage - directions changed, largely 

 as the result of glacier erosion ; but I have not examined the comitry in 

 sufficient detail to speak definitely on the matter, though I feel certain 

 that it will furnish very interesting material bearing on the much-discussed 

 question of the efficiency of glaciers as erosive agents. 



(6.) Bnkaia Glaciers. 



The glaciers of the main Rakaia basin are (1) those on the flank of 

 Mount Murray, (2) those at the head of the river, and (3) those on the 

 north side in the system of valleys which rise in the main divide and run 

 towards the south-west. 



Fig. 3. — Map of Rakaia Glaciees. 



On the north side of Mount Murray there are small cliff glaciers heading 

 a stream known as the Little Washbourne, which joins the Rakaia about 

 five miles above the outlet of the Lake Stream. Another glacier, of slightly 

 larger size, heads a ravine on the north-west of Mount Gould, and almost 



