34 Transactions. 



' When the great glaciers which were thrust forward to the 

 outlets of the alpine valleys receded, and the ground moraines 

 which were left behind were dried up by the north-west wind 

 (Fohn), then the fine dust was blown far over the surface right 

 up to the sea. The deposit of dust accumulated in the form of 

 the fertile loess. Then, as we see in many parts of Germany, 

 the loess covered the land-surface, sometimes from half a metre 

 to a metre in thickness, and sometimes from 10 to '15 metres. 

 Where it breaks away on the upper edge of the river-bed region 

 it forms perpendicular walls," and here long-buried moa-bones 

 frequently appear. But even now the loess formation is going 

 on. We have ourselves seen how thick are the clouds of dust 

 whirled up from the broad, shingly river-beds by the north-west 

 wind and spread over the cultivated land. The rain, when it 

 falls afterwards, unites the dust with the agricultural land. 

 A part of the fertility of the eastern plains depends on the loess 

 covering." 



After a general consideration of the evidence, and from my 

 own observations, I have come to the conclusion that the loess 

 has not been beneath the sea. It is very thick on the hills 

 between Tai Tapu and Birdling's Flat, but is completely swept 

 away from those places which have been exposed to lake or sea 

 erosion. It could not exist in its peculiar position on the tops 

 of spurs, &c, if they had been washed by the sea since it was 

 laid down. Further, if it had been a marine deposit it should 

 have covered the whole landscape irrespective of its form, and 

 it is unlikely that it has been removed by denuding agents 

 from so many places and left comparatively untouched on the 

 spurs and the sides of valleys. I am therefore inclined to think 

 it was a wind deposit during the steppe conditions of a higher 

 land and drier climate, with severe windstorms sweeping from 

 great river-beds greater clouds of dust than are seen now in the 

 Rakaia and Waimakariri, although these are by no means of 

 insignificant proportions at the present time. 



The deposit of loess covers up the old shore platforms on 

 the south-west side of Banks Peninsula, therefore the depression 

 during which they were formed was pre-loess, and therefore 

 before the great glacier extension. If this is really so, it serves 

 to emphasize the recency of this extension. The general order 

 of events would therefore be a period of low laud, when the 

 marine terraces were formed, then an elevation in glacier times, 

 followed by a depression till now, with probably minor periods 

 of slight elevation. There is a slight elevation going on now, 

 as maybe seen from the wave-worn caves at Sumner qo"w several 

 feet above high-water mark, and the bands of sand-dunes between 

 Christchurch and the sea. This, no doubt, accounts for the low. 



