Wellington Philosojyhical Society. 525 



the surface at least of tlie Canterbury plains was not so simple a process as stated. As 

 stated, it might suit the conditions of a small deposit, but these fans were twenty to 

 thirty miles m diameter, and could only have been built up by successive changes in the 

 courses of rivers as they gradually raised their beds and then broke away from them. 

 The resulting fan was made up of many river beds, radiating from one point or gorge. A 

 most important feature not mentioned by the author was the formation of secondary fans 

 in front of those earlier ones formed by the gradual erosion and deepening of the notch or 

 gorge in the rocky bed through which the river was finally liberated from the mountains. 

 As this notch was lowered the river became confined to a deep terraced valley excavated 

 in the sliingle of the earher fans, the sliingle removed going to raise the bed in a lower 

 part of its course. This, in his opinion, gave rise to the apparent concave sm'face of the 

 plains in the author's section. 



Mr. Travers pointed out that the essential point in the fan-like arrangement of 

 detritus was the diminished velocity of the river after escaping from the upper part of its 

 course whence the detritus was derived. He described the prodigious effects of the great 

 fiood of 1867 on the valley deposits of the Wairau Eiver, high level terraces of gravel 

 having been completely swept away by lateral tributaries, leaving shelves of bare rock, 

 while the rocky and previously impassable bed of the main river was converted into a 

 smooth surface or plain for miles. That was the effect of one short flood, and he 

 thought that it was evidence that no flood of similar magnitude had occurred since the 

 terrace skirting the valley had been formed. 



Dr. Hector stated that the amount of detritus carried out to sea on that occasion had 

 added ten chains width to the beach for miles along the coast, so that tl^e fences running 

 out on the shore had to be lengthened. 



Mr. Maxwell, in reply, considered the remarks made did not conflict with the 

 views expressed in this paper, but only extended their application. His object was to 

 refute the idea that the changes in the direction of such rivers could be controlled by the 

 rotation of the earth, as suggested by Dr. Haast and Mr. Baines in the last volume of 

 " Transactions." 



2. " Some Notes on the D'Urville Island Copper Mine," by S. H. 

 Cox, F.C.S., F.G.S., Assistant Geologist. 



ABSTRACT. 



The mine is situated at the southern end of D'Urville Island, the coj)per 

 occurring in a belt of serpentine, v.-hich may be traced from the Dun Moun- 

 tain, at Nelson, to the Croixelles, and again throughout the length of 

 D'Urville Island. This belt of serpentine is in contact with certain coarse- 

 grained green sandstones and banded slates of the Maitai series, in which 

 veins of quartz with nests of pyrites occur, the strike of the slates being 

 about N.N.E. 



Outcrops of cuprite, coated with malachite and azurite, have been traced 

 at intervals over a distance of 900 yards, or thereabouts, in a N.E. and 

 S.W. direction, these outcrops generally occurring on a bare ridge of 

 serpentine, which is about the centre line of the piece of ground which has 

 been leased from the Maoris for mining operations, and four small shafts 

 have been sunk to prove the ore at different points, These shafts do not 



