1866.] LOCKE-TBAVERS LAKE-BASINS. 259 



The glacier which deposited the lower moraine must have been a 

 stupendous one, for there are erratics and " roches moutonnees " on 

 the sides of the mountains, to the height of 1000 feet and upwards. 

 The valley is about a mile wide at the moraine, increasing in breadth 

 opposite the '* Ada " and *^ Christopher " rivers, the valleys of which 

 were evidently occupied by branches of the great glacier. The length 

 of the main glacier was about 23 to 24 miles, that of the Ada branch 

 about 8, and that of the Christopher branch 5 or 6. The mountains 

 on each side of these valleys are extremely steep, and the main valley 

 now rises about 35 feet to the mile. 



Looking to the appearance of the valley below the moraine, there 

 is no doubt that the glacier formerly extended as far as the junction 

 of the Dillon and Hope, but I did not see in the upper part of the 

 latter river, or in the Dillon below the junction, any traces of glacial 

 action. About ten miles below the junction the waters of the united 

 rivers debouch upon the Hanmer Plains, and thence find their 

 way through a rocky gorge into the Hurunui Plains. On the sides 

 of the mountains bounding the Hanmer Plains, south of the river, 

 we find a succession of old terraces, the uppermost of which is fully 

 700 feet above the general level of the plains. The lowest terrace 

 rests upon the rock through which the river now flows, upon which 

 it forms a capping of considerable thickness. I conceive that the 

 material of these terraces was deposited during the same period of de- 

 pression which gave rise to the Post-pliocene boulder beds and gravels 

 on the north side of the range, and that the now rocky channel of 

 the river has been excavated since the reelevation of the land. 



Keverting to the great moraine above referred to, I found that 

 the main river, aided by the Henry, had cut a way through the 

 moraine matter, exhibiting sections from 80 to 100 feet in height. 



In its course through the gorge below the Hanmer Plain, the 

 river has cut a channel through solid rock 120 feet deep below the 

 level of the lowest shingle terrace, showing the enormous wearing 

 power of water charged with sediment, even though flowing on so 

 apparently slight a fall as 35 feet to the mile. 



There is, I conceive, every probablity that the vaUeys of the 

 Dillon and Clarence were filled vdth ice at the same time as the 

 present sites of lakes Arthur and Howick, although the bed of the lake 

 formerly existing behind the moraine dam of the Dillon has since been 

 fiUed up, the river-borne matter being banked up against the sloping 

 face of the moraine. What the original depth of that lake may 

 have been it is impossible to say ; but there is no reason to suppose 

 that it may not have rivalled those on the north side of the chain. 

 I attribute the rapid filling up of this lake-bed to the facts, that the 

 mountains bounding the valley of the DiUon are exceedingly steep, 

 are composed of easily disintegrated sandstone, are very bare of ve- 

 getation, and present in many places for thousands of feet in height 

 and for miles in length, little else than avalanches of broken stone ; 

 whilst those which bound the Lakes Arthur and Howick are densely 

 wooded, are very much less steep, and are composed of granite and 

 other hard crvstalline rocks. 



