610 Transactioihs . 



This is contradicted in England, where, as Geikie tells us, no terminal 

 moraine marks the southern limit of the ice-sheet that crept over Britain. 

 But in New Zealand we have the Taieri coastal moraine, for size without 

 a parallel in any other part of New Zealand, or even in Great Britain ; 

 therefore the balance of evidence as to an ancient ice-sheet lies with New 

 Zealand as against England, which, although possessing no terminal 

 joaoraine, is admitted to have been covered with an ice-sheet. 



(2.) The occurrence of till or boulder-clay over almost the whole 

 area covered by the ice-sheet. 



When tested against British experience we find that this criterion, like 

 the first, also fails. In Scotland, although ice-covered in the Pleistocene 

 from end to end, the till is mainly confined to the maritime benches, coastal 

 plains, and lowland valleys. Altogether it does not cover more than 25 

 per cent, of the total area. England and Wales were covered with a con- 

 tinuous ice-sheet as far south as the valley of the Thames, and yet we find 

 that the glacial drift is most irregularly distributed, altogether covering 

 less than 12 per cent, of the glaciated area. In New Zealand we have the 

 great Taieri Moraine, the Kaikorai boulder-clay, and the loess covering 

 the coastal hills at Oamaru and Timaru, the Lyttelton Hills, and Motanau 

 Downs ; loess being, as we have seen, a deposit of purely glacial origin. 



The Taieri Moraine is admitted to have been formed by a glacier that 

 descended from the highlands between the Clutha and Taieri rivers. The 

 glacier that filled the Taieri Basin and formed the great coastal moraine 

 must have presented a front from thirty to forty miles long at the least. 

 And, since this gigantic glacier surmounted hills over 1,000 ft. high near 

 Milton, it must also have flowed southward into the lower Clutha Valley — 

 a conclusion strengthened by the smooth, flowing contours and chain of 

 shallow lagoons on the Clutha side. To those not familiar with the geo- 

 graphy of this place, it should be mentioned that the rise between Milton 

 and the Clutha Valley is only some 150 ft., the area between the Toko- 

 mairiro Plain and the lower Clutha being occupied by low, round, ice-shorn 

 ridges varying from 200 ft. to 300 ft. above sea-level. 



My object is to show that this Taieri ice-sheet must have been of 

 gigantic proportions. Now, if the chmatic conditions in the arid region 

 of Central Otago allowed the accumulation of this great ice-sheet, what, 

 I ask, must have been the climatic conditions on the higher, less arid 

 mountainous region of western Otago ? Would not that area, as already 

 shown by Hutton, be also covered with a continuous ice-sheet ? Dr. 

 Marshall seems to have anticipated this difliculty, for he tells us — and this 

 is only a hypothesis suggested by Geikie and Chamberlin — that the sup- 

 posed non-glaciation of eastern Europe, Siberia, and Alaska was due to 

 the aridness of the climate — that is, to the absence of precipitation. And 

 from this he argues that one valley may contain a glacier and the next to 

 it no glacier. Unfortunately for the application of this argument to New 

 Zealand, the site he has selected for the gathering-ground of the Taieri 

 ice-sheet is situated in the most arid region of Central Otago, where, as in 

 Siberia, the snowfall should have been too small to maintain such a mass 

 of ice as that which radiated from the highlands between the Clutha and 

 Taieri watersheds, filled the Taieri and Tokomairiro basins, and crept over 

 the coastal hills to the present coast-line. 



I contend that the great ice-sheet that descended from the highlands 

 of Central Otago was a part of the greater ice-sheet that occupied the 

 Wakatipu and Wanaka areas. 



