136 E. C. ANDREWS. 



of feet. It is probable that the Tertiary strata found in 

 the valley have been let down by Late Tertiary faulting. 



Similarly for all the large Alpine lakes and most of the 

 magnificent fiords of the west coast. In each case most 

 intense ice action is evidenced, but there are also signs of 

 formative activities other than those of streams. In some 

 cases, for example, Dusky Sound, Doubtful Sound, Lake 

 Manapouri and Lake Wanaka, it is highly probable that the 

 basins have originated in heavy faulting action with the 

 production thus of senkungsfelder, and that the senkungs- 

 feld valleys have in later time been modified and extended 

 headwards as canons, first by ordinary streams and then by 

 ice action. The evidence for this conclusion is simply an 

 application of the principles dealt with in this note and 

 consists of the intimate association of topographical sur- 

 faces in quite different stages of development in dense 

 resistant geological complexes. Some of the lake and 

 sound basins, such as those of Wanaka, Hawea, Wakatipu, 

 Manapouri, Te Anau, Doubtful, Breaksea and Dusky Sounds 

 are situated also where one could not expect them to be, if 

 they had been the products of stream corrasion, and their 

 maximum depths moreover, occur in places where the 

 maximum stream scour could not have taken place. On 

 the other hand the canons which open out into them are 

 generally such as might have originated in stream action. 



It may be that certain large Alpine lake basins in other 

 regions may be due also both to dislocations and to intense 

 water and glacial action during a still later period. 



