Park. — Striated Erratic Block of Andesite in Rangitikei Valley. 137 



In 1909 I expressed the opinion that the piles of andesite in the middle 

 and lower portions of the Hautapu could have been transported and piled 

 in their present places by no known agency but glacier-ice descending from 

 Mount Ruapeliu. This mountain is a massive volcano, rising to a height 

 of 9,000 ft. above the sea. The glacier* at present existing on it lies in a 

 basin encircled by peaks ranging from 7,000 ft. to 9,000 ft. high. 



Mount Euapehu is the highest mountain mass in the North Island of 

 New Zealand. It lies in latitude 39° 15' south, and even now possesses a 

 glacier nearly two square miles in extent. The audesitic erratic in the 

 Rangitikei Valley lies in latitude 39° 45' south. 



The presence of the morainic piles of andesitic material in the Hautapu 

 Valley and the occurrence of the Mangaweka striated erratic in the Rangi- 

 tikei Valley show that in the Pleistocene period a valley glacier threaded 

 its way down the Hautapu Valley till it reached the Rangitikei Valley. 

 Both the Rangitikei and Hautapu Rivers ran in deep rectangular troughs 

 excavated in the floor of the old glacial valley. 



In the Pleistocene, glaciers covered much of the highlands of Tasmania, 

 and, according to Professor J. W. Gregory, F.R.S., descended within 400 ft.- 

 of the sea. This view has been confirmed by Professor Bdgeworth David, 

 F.R.S., who has stated that the glacier-ice came to within a few hundred 

 feet of sea-level, if not down to sea-level itself. 



After all, it does not seem very remarkable that a glacier should have 

 descended to within 1,000 ft. of the sea in the southern end of the North 

 Island during the great Pleistocene glaciation of New Zealand. 



Art. XVI.- — The Orientation of the River-valleys of Canterhury. 

 By R. Speight, M.Sc, F.G.S. 



[Bead before the Philosophical Institute of Canterbury, 1st September, 1915.] 



The remarkable orientation of the river-valleys of Canterbury has attracted 

 the attention of numerous writers on physiographic subjects since the main 

 features were first pointed out by Edward Dobson in his report for the 

 year 1865 on " The Possibility of constructing a Road through the Otira 

 Gorge " furnished to the Provincial Council of Canterbury. This report 

 was fully noticed by Haast in his " Geology of Canterbury " (p. 174), and 

 by McKay in his report on Marlborough and Amuri Counties (" Reports 

 on Geological Explorations for 1890-91," p. 26). Reference has also been 

 made to it in Kitson and Thiele's paper on the Upper Waitaki basin 

 (Geographical Journal, vol. 36, 1910, p. 547) and by Gregory in his 

 book on " The Nature and Origin of Fiords," 1913 (p. 366). In view of 

 these references it may not be altogether irrelevant at the present time 

 to re-state the case and to examine in the light of later observations 

 the evidence for and against this hj^pothesis. 



Before dealing with the origin of the valleys it is as well to consider 

 their arrangement in order to imderstand how far the statement made 

 Tjy Dobson is correct. He says {loc. cit., p. 50), " In addition to the folding 



* J. Park, " Geology of New Zealand," 1910, p. 203. Fig. 94 shows a portion of 

 "the existing Ruapehu Glacier. 



