132 PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 7/ 



by the water issuing from the termination of the retreating glacier 

 collecting in the depression. After this the form and extent of the 

 lake became altered by the formation of a delta by the glacier- 

 stream. 



Dr. Haast concluded his paper as follows : — 



" The old beds of glaciers are in all stages and conditions in the 

 New Zealand Alps, from the deep narrow gorge-like character, with 

 an outlet of clear, neai-ly colourless water (Lake Wanaka), to the 

 shallow wide expanse, with an outlet the water of which is always 

 coloured from glacial mud (Lake Pukaki and Lake Takago), or they 

 are filled up or drained by the removal of part of the terminal 

 moraine-masses, and the cutting of a channel through the rocks 

 (Rangitata), or from extensive swamps through which the river 

 meanders sluggishly (Valley of the Aturia). 



" Often several of these drained lakes occur, one above the other, 

 until they reach the present glacier-moraine, through which the river 

 has forced a gorge-like passage, and behind them an expansion of 

 the valley, with shingle-flats or swampy grounds. 



" The rocky basins occur on both sides of the New Zealand Alps, 

 as, for instance, Lake Brunner, Lake Eatorna, and Lake Eataiti, on 

 the western side of the central mountain- chain of the Province of Nel- 

 son, whilst by far the greater part has been filled up as lying on the 

 steep western side of the Alps, where in consequence greater destruc- 

 tion has taken place through denudation (Marnia plains, expansion 

 of the YaUey of the Grey, before it enters the plains, &e.). 



"I have not made any allusion to the unequal ratio of elevation 

 and subsidence, which wiU be necessary to explain many apparent 

 anomalies ; but I may state that, since the Pleistocene epoch, the 

 greatest subsidence in this island has taken place towards the south- 

 west, to which already the greater extent of the Alpine lakes in the 

 Otago Province and the less altitude of the mountain-chains point, 

 although they show enormous glaciation in former times ; whilst the 

 researches of Dr. Hector on the west coast of Otago have conclusively 

 shown that its deep fiords are simply the channels of former gla- 

 ciers, now depressed below the level of the sea, but still showing by 

 their configuration that they are rock-basins. 



" If this hypothesis, and the deduction drawn from it, be applied 

 to other countries where the same phenomena are to be met with, 

 I have not the least doubt that they will be able to explain there 

 also the existence of rocky lake-basins, and why many others have 

 been obliterated. 



" In conclusion, I may state that all my observations have shown 

 that the glaciation of New Zealand (like that of other countries 

 generally) has been brought about by physical causes now in exist- 

 ence, and that I hope soon to be able to lay before the Society 

 a more detailed paper, with illustrations, on the same important 

 subject." 



