HuTTON. — On the Formation of Lake Wahatipu. 395 



to show evidence of it by some, at least, of the rivers being deflected to the 

 north ; but the very contrary is the case, for the Jacobs River, Oreti, and 

 Mataura have all been deflected towards the south. The evidence, indeed, of 

 the river system goes to show that the central part of the South Island has 

 been more elevated than the southern part, a movement which must have 

 tended to empty Lake Wakatipu. 



The next supposition that we can make is that this unequal elevation and 

 depression was not universal bnt local, the country north of Lake Wakatipu 

 having alone been depressed. If, however, this local depression occurred 

 between the head of the lake and the west coast it would have emptied Lakes 

 "Wanaka and Hawea which lie north of it ; and if the depression was north of 

 Lake Wanaka it would have emptied, in the same way. Lakes Pukaki and 

 Tekapo, which are further north again, for all these lakes lie in a more or less 

 north and south direction, with the south end dammed up. There appears, 

 however (Hochstetter's "Kew Zealand," p. 484), to be one place, off Cliffy Head, 

 from which many of these lakes radiate, so that if the depression had taken 

 place there it might perhaps have formed them all. But if we assume this, we 

 again encounter those difficulties that I at first pointed out ; for by this theory 

 the central part of the Island must have been depressed at least 15,000 feet 

 more than the north and south, and the deep sounds instead of being found on 

 the south-west of Otago and the north of Marlborough, should occur in 

 Canterbury, and the rivers should be deflected to the north in Otago, and to 

 the south in Nelson and Marlborough ; for the fact of all the rivers on the 

 Canterbury plains having cut deep gorges through the alluvial deposits, shows 

 clearly that their volocities have not been reduced by a greater sinking of the 

 west than of the east coast. The Nelson lakes, moreover, would require some 

 different arrangement again to account for them. 



We may still make a third supposition as to the formation of Lake 

 Wakatipu by supposing it to be owing to a small local subsidence in that 

 area alone, but this is disproved by the regularity of the strike of the rocks 

 from one end of the lake to the other, and the dip of the beds is so slight that 

 any movement by which the upper or central portion of the lake had been 

 depressed could not possibly escape detection, and I had this constantly in my 

 mind when examining the district last summer. 



In order, therefore, to explain the formation of these lakes by unequal 

 subsidence, and at the same time to account for other phenomena observed 

 round the coast, we should have to imagine such a complicated system of local 

 depressions and upheavals that they would more resemble the contortions 

 produced by lateral pressure than any movements that we know, or have any 

 right to assume, are going on at the surface of the earth. 



In the section given by Dr. Hector {Trans. N.Z. Inst., II., p. 372) we see 



