W. Tjravers. — Supposed Pleistocene Glaciation of New Zealand. 419 



These rivers are liable to great floods, arising from causes similar to those 

 which affect the head waters of the Rhone, and the quantity of shingle and 

 silt which they then carry to sea is enormous. The plains are composed 

 of river alluvium, in a deposit which is evidently of considerable thickness, 

 for, except at points where the larger rivers which traverse them have cut 

 through these deposits near their own debouchures from the mountain range, 

 the foundations upon which they lie are nowhere observable. 



As will have been noticed, Dr. Haast speaks of the surface materials 

 composing these plains as covering the foundations upon which they lie, with 

 an almost uniform gradient, which I have assumed to mean, that their surface 

 slopes almost uniformly from the most elevated parts near the foot of the 

 mountains to the level of the sea, a point of great importance in connection 

 with any enquiries into the manner in which these deposits were originally 

 spread over the area which they now occupy. The character of the country, 

 both in the neighbourhood and to the southward of Timaru, is sufficiently 

 given in an extract from another report of Dr. Haast's, which will be found in 

 the sequel, and, therefore, need not further be referred to here. 



As regards the indigenous vegetation of the district under consideration, I 

 may state, generally, that, with the exception of occasional but by no 

 means common or extensive patches of forest, its eastern side (taking from 

 the summit of the dividing range) supports only grasses and other herbaceous 

 plants, whilst the whole of its western side, below sub-alpine level, is 

 densely clothed with luxuriant forest. The surface of Banks Peninsula is 

 pretty evenly divided between grass and forest land, the latter probably 

 predominating. The flora of the South Island is somewhat less rich in genera 



& 



and species than that of the North Island, and would, probably, not yield 

 more than 750 species of flowering plants, of which one-fifth would be common 

 to New Zealand and Australia, and one-tenth to New Zealand and South 

 America, whilst not less than 500 species would be peculiar to New Zealand. 

 But it must also be bome in mind that the major part of the flora has a semi- 



xis 



plants 



the rigour even of an English winter. 



As is well known, the terrestrial fauna of New Zealand consists almost 

 exclusively of birds, and of the 150 species which may be considered as truly 

 belongin 



Island, Amongst those which occur there I may particularly mention the two 

 species of wingless birds peculiar to the South Island, namely, Apteryx oweni 

 and Apteryx australis, as well as the Ocydromus australis, and the singular 

 StHngops habroptilus, in the first of which the wings are incomplete, and in 



both are useless for purposes of flight. I must also, in this connection, mention 



