Park. — The Great Ice Age of New Zealand. 601 



cliaracter of the transported blocks. The Taieri Moraine, for example, 

 contains no striated boulders, and their absence has not been advanced 

 by any one as an argument that the deposit is non-glacial. 



Dr. Marshall* agrees with me that the material in the Hautapu glacial 

 drift has been derived from Kuapehu, but says it is a river-gravel. I am 

 confident that no one who has examined this deposit could possibly mis- 

 take it for a river-gravel ; and I can only assume that Dr. Marshall has 

 never seen the angular, rubbly, high-level andesitic glacial till discovered 

 by me, and so well exposed in the railway cuttings, or that he has mis- 

 taken the resorted stream-gravels on the banks of the Hautapu and its 

 tributaries for the glacial deposit itself. I have elsewhere stated that 

 these stream-gravels are merely a local rewash of the great andesitic glacial 

 deposit formed at the places where the streams have cut through it. 



As Dr. Marshall still maintains that the glacial drift in the Hautapu 

 Valley is a river-gravel, it becomes necessary to state the criteria of a 

 river-gravel as defined bv recognised authorities. They are as follow : — 



(a.) The material is water - worn, and becomes more and more 



rounded as it travels away from its source. 

 {h.) The material is coarsest near the source, and gets finer and finer 



with increasing distance from the source, 

 (c.) The material is sometimes sorted into irregular beds that often 



exhibit current-bedding. 



Judged by these criteria, we find that the Hautapu glacial deposit is 

 everything that a river-gravel should not be. 



In the first place, the material is not water-worn, but angular ; and, in 

 the second place, it is not coarsest near its parent source, but at its extreme 

 south hmit. It contains but little water-worn material, but, where typically 

 developed in the Hautapu Valley, consists of a rock-rubble of angular 

 andesite blocks, set in a matrix of gritty sands and rubbly clays. 



The first to state that Otago was covered with a continuous ice-sheet 

 was Mr. J. T. Thomson,! for many years Chief Surveyor of Otago, and 

 afterwards Surveyor-General of New Zealand. Mr. Thomson was a keen 

 student of the development of the surface-forms and topographical fea- 

 tures, and brought to New Zealand a knowledge of the evidences of ancient 

 glaciation as seen in Scotland, and of the work of valley glaciation in the 

 Himalayas in India. By profession, by natural bent and experience, Mr. 

 Thomson was perhaps better qualified to express an opinion on the glaci- 

 ation of Otago than any other physiographer since his time. 



In a letter to the Otago Daily Times of the 13th May, 1909, criticizing 

 my presidential address to the Otago Institute, Dr. Marshall states that 

 Mr. Thomson " went hot-headed for the covering of the whole southern 

 portion of the Island with an ice-sheet." I hold no brief for Mr. Thomson, 

 but, as one who knew him and the thoroughness of his work, I have no 

 hesitation in saying that Dr. Marshall's statement does less than justice 

 to the temperament and mental attitude of Mr. Thomson, who was an 

 accomplished geographer and distinguished mathematician. Mr. Thomson 

 was no hot-head, nor were his views as to the ancient glaciation of Otago 

 hot-headed or precipitate, for he tells us that his conclusions as to the 

 glaciation of the South Island were arrived at as the result of observations 



* P. Marshall. Evening Star, Diinedin. 12th August. 1909. 

 t J. T. Thom.son, Trans. N.Z. In.st., vol. vi, p. 312; 187(5. 



