316 Transactions. — Geology. 



mountain out of which it issues 8,500 feet. Testing the curve of the valley- 

 bed by the elliptic curve, in tlie same manner as given for the Manuherikia, 

 we find the following result : — 



By Ellipse. By Survey. Differences. 



At source {a) 0000 



ah) 6672 



At intermediate points <^ \ I c..-, -. 



i (e) 8475 



At exit into sea ... ( f) 8500 



0000 

 712.3 



7725 

 8138 

 8291 

 8500 



000 

 551 

 109 

 273 

 184 

 000 



les to the north- 



The Waitaki is about 140 miles in length, rising some mil 

 east of Mount Cook, whose elevation is 12,460 feet, and a painting of which 

 is lying on the table, the copy of a sketch that I made when exploring the 

 country in December, 1857. The scenery is the most grand and rugged in 

 New Zealand, and can scarcely be surpassed in barrenness and wildness in any 

 part of the world. I, at that time, with the privilege of an explorer and 

 surveyor, named the feeding waters of the Pukaki Lake " Upper Waitaki," 

 and their valley "The Yalley of Sand." Dr. Haast, following me some years 

 afterwards, has, no doubt inadvertently, altered these names to " Tasman," and 

 the great mountain next to Mount Cook, which I, appropriately I opine, named 

 " Mount Stokes," he has altered to " Sefton." From its alpine valley the 

 Waitaki issues out on the Mackenzie Plains — named after a notorious sheep- 

 stealer, by way of relief to the other good names in the Province — passing in 

 its course through the Pukaki Lake ; from thence it pierces the deep gorges 

 of the Ben More and Kurow Mountains, after which it issues on the Waitaki 

 Plains, near the sea. That one of the largest rivers in New Zealand, such as 

 this, in passing over so many obstacles, should yet have its bed in such near 

 conformity with the curve of the ellipse, was again striking, and wherein the 

 divergences occur just where the mountain and rock obstructions are greatest. 

 Thus a law of erosion of great power was again indicated, and so further 

 enquiry stimulated ; and I may here remark that while one great abrasion of 

 surface has undoubtedly taken place, another, of no less significance, is 

 exhibited by the section in the upper valley and Pukaki Lake — the effect of 

 the action of mountain glaciers, whose effects have already been pointed out 

 by my friend Mr. McKerrow (Trans. N.Z. Inst., Vol. III., p. 254), and to 

 which subject I may recur. 



Leaving the Waitaki Yalley, I then proceeded to investigate the levels of 

 the bed of the Shag River. This river has a short course of about 39 miles, 

 having its source in Kakanui Peak, whose elevation is 4,978 feet above the sea. 

 The river has a course through very rugged country ; it is very tortuous, yet 

 the section proves another very close approximation to the ellipse. For the 

 calculation of the ordinates, we have : length of valley equal to 199,700 feet, 



