Marshall. — The Glaciation of yew Zealand. 337 



special evidence in favour of the glacial origin of this material. At 

 all events, even if a glacial origin could be proved for the material 

 of this mound, 8 ft. by 5 chains, such an occurrence can hardly be 

 seriously used as an argument in evidence of the existence of an ice-sheet 

 in eastern Otago. 



(2.) Boulder-clays : The coastal area from Timaru to Kaitangata has 

 been examined by numerous geologists. Of these, Hector, Hutton, Haast, 

 McKay, and Park have repeatedly failed to record the occurrence of any 

 till or boulder-clay. Hutton regarded all the surface clay of South Canter- 

 bury and North Otago as a marine silt. Haast described it as a loess, and 

 his description has been strongly supported by Hardcastle, and adopted by 

 Heim and Speight. Park, in 1904, referred to the Oamaru loess as yellow 

 silts. The loess of Timaru and Oamaru cannot be distinguished from the 

 similar deposits that form a nearly continuous covering over the Canter- 

 bury Plains, and extend to the height of 800 ft. on Banks Peninsula. 



My own microscopic examination of this material strongly supports 

 Haast's loess theory. Not only have I seen imder the direction of Mr. 

 Hardcastle a few pebbles of small size of well-rolled material, but also well 

 Avithin the mass of the deposit a small amount of bog-iron ore, Avhich was 

 formed in small depressions of the surface on to which the dust was blown 

 from the riyer-beds. 



Microscopic examination shows that the loess consists of minute rounded 

 grains, mostly of quartz, and this is very characteristic of wind-blown 

 material. 



The clays about Dunedin are of a very different character. In all cases 

 the only recognisable mineral grains that they contain are those of the 

 most resistant minerals contained in the underlying rock — a matter that at 

 once suggests that they have been formed in situ. That this explanation 

 is in many cases correct is proved by the occurrence of sections which show 

 the gradual degradation of the rock into clay. One that is particularly 

 instructive is to be seen at the top of Roslyn. where the Rattray Street 

 tramway passes through a cutting at the top of the hill. The boulders in 

 the clay and on its surface are in almost all cases identical in composition 

 with the sound rock below. In those cases in which this identity of nature 

 is not found the boulders belong to another adjacent lava-flow that lies 

 above it ; but there are very few instances of these. 



There are a few places at relatively low levels where there is a layer of 

 well-rounded pebbles and boulders beneath the clay. These mark old 

 marine shore-lines. In previous publications it has been shown that the 

 present shore-line bears unmistakable evidence of elevation, for in many 

 places, especially at Sea View, there are marine terraces now some 200 ft. 

 above sea-level. The clay that covers the boulders in the localities referred 

 to has been washed down the hillside on to them. In a typical instance at 

 Caversham the clay that covers the boulders consists almost entirely of 

 quartz grains and remains of Foramiiiijera. These are also the main con- 

 stituents of the underlying rock and of the surrounding rock over a small 

 area. Although this marine sandstone has quite a small outcrop, and is 

 surrounded by volcanic rock, there is very little admixture of other material 

 that could have been derived from volcanic rocks. 



(3.) Roches moutonne?s : No geologist has yet pointed to or described 

 in any scientific publication any roches moutonnees near the coast-line. 

 Until such features have been described and the descriptions discussed, it 



