Si'ki(;ht, Cockayxk, Lmxc — Maim/ Arroirsmifh Dixirirf. 317 



PAET 1.— PHYSIOGRAPHY. 

 By R. Speight, M.A,. M.Sc, F.Ct.S. 



[Read before the Philosophical Instifvte of Cankrbxiry, 1st June, 1910. \ 



i. Introductory. 



Tins paper deals with the physiography of a part of Canterbury, which is 

 little known even noAv. Althoiigh reference is made to its general physical 

 features, those which depend on glaciation, both present and past, receive 

 most attention. In presenting this account I have to acknowledge my 

 indebtedness to Sir Julius von Haast on points so numerous that it is 

 impossible to mention them in detail. I therefore take this opportunity 

 to make a general acknowledgement of my debt, and also to express, as 

 one who has followed in his footsteps, even if a long way after, my appre- 

 ciation of the work which he did in this locality nearly fifty years ago. 

 Considering that physiographicai geology Avas almost unknown as such at 

 the. time when he visited the head-waters of the rivers referred to later, 

 it is most surprising to find what a Avonderful grasp he had of the principles 

 which underlie that phase of geological study, and, even if he did not know 

 processes and re.3ults by the names vvhich are applied nowadays, he cer- 

 tainly had a proper appreciation of their importance, and clearly recognized 

 their operation in nature. 



I must also acknowledge my indebtedness in a minor degree to Captain 

 Hutton and to S. H. Cox for their descriptions of portions of this area. 



My own conclusions are based on observations made during four 

 separate journeys to various parts of the district. 



2. Mountain Systems. 



{a.) Topography. 



(See map, p. 318.) 



The district dealt with in this paper lies at the head of the Ashburton 

 and Rakaia Rivers, and forms part of the eastern slopes of the main range 

 -of the Southern Alps, in lat. 43° 20' south approximately. In this part of 

 the range its average direction is north-east to south-west, but owing to 

 extensive erosion by rivers and glaciers the valleys on either side dovetail 

 into one another in a most remarkable manner, so that the actu.al crest 

 is a very irregular line. The principal peaks, taking them in order from 

 Wliitcombe Pass to the head of the Rangitata River, are the following : 

 Louper Peak (8,165 ft.). Mount Whitcombe (8,656 ft.), Blair Peak (8,185 ft.). 

 Malcolm Peak (8,236 ft.), and Mount Tyndall (8,282 ft.). Running east 

 from the main range, and forming the main divide between the upper 

 valleys of the Rangitata and the Rakaia, is an elevated ridge connect- 

 ing the Arrowsmith Range with the central mountain system. This 

 ridge is everywhere over 5,000 ft. in height, and has several prominent 

 peaks on it, notably Mount Goethe (over 6,000 ft.) and Mount Murray 

 (7,065 ft.). The Arrowsmith Range stretches in a north-east to south-west 

 direction, generally parallel to the Southern Alps, and rises to a height of 

 9,171 ft. in Mount Arrowsmith itself, with numerous minor points about 

 8,000 ft. Mount Arrowsmith is thus higher than any peak in the vicinity, 

 and, indeed, is higher than any peak on the main divide behind it with the 

 exception of those in the Mount Cook group. The same peculiarity in the 



