Speight. — Structural and Glacial Features of Hurunui Valley. 103 



of the Rakaia. The arrangement is as follows, taking the valleys in their 

 turn, commencing from the north : — 



(1.) The main valley of the North Branch leading into Lake Sumner. This 

 has a general east-and-west trend, with wall-like sides in good alignment, 

 I nit broken by tributary valleys, especially on its northern side. Lake 

 Sumner occupies a continuation of this valley, but about half-way along 

 the lake the trend assumes a north-west and south-east direction more in 

 agreement with that of the others. This corresponds in direction and 

 salient features with the main valley of the Wainiakariri. but the landscape 

 characters are on a smaller scale. 



(2.) The set of subparattel valleys lent/inn from the vicinity of the head of 

 Lake Sumner, near Lake Katrine, and running south-east. At the head of 

 the system there is only one main valley, but it breaks up within a short 

 distance into distributaries consisting of- (i) A valley immediately to the 

 south of Lake Sumner and divided therefrom by a ridge of which the peaks 

 known as The Brothers (4,563 ft. and 4.507 ft.) are the highest points ; 

 (ii) a valley in which lies Lake Sheppard, divided from (i) by a discontinuous 

 ridge ending in The Sisters (3,281 ft.) ; (iii) a valley in which lies Lake Taylor, 

 divided from the former by Conical Hill (2,783 ft.) and from the valley of 

 the South Branch by the Oronoko Range. These valleys are quite analogous 

 to those in the Wainiakariri basin, which may be called (i) the Lake Black- 

 water Valley, (ii) the Lake Sarah - Sloven's Creek Valley, and (iii) the Lake 

 Grassmere - Lake Pearson - Winding Creek Valley. They also resemble the 

 still more remarkable and perfect system to the east of the Rakaia basin 

 in the vicinity of Lake Coleridge. 



The ridges which divide these valleys are analogous in their physical 

 characters. They are very steep-sided, with somewhat narrowed cross- 

 section, so that when viewed end-on they appear conical ; hence the frequent 

 occurrence of such names as " Sugarloaf " and " Conical Hill ** in North 

 Canterbury. But when viewed from the side they form long ridges cut 

 into well-defined saddles (c/. Mitre Peak). When this saddle is low and 

 little elevated above the floor of the valley in the vicinity the ridges become 

 isolated hills, which are often in pairs or linear series, and give rise to 

 such names as " The Brothers " or " The Sisters.'" 



The valleys indicated above junction with the main valley of the North 

 Branch after it leaves Lake Sumner and takes the first decided bend of the 

 river to the south-east. It soon afterwards receives the South Branch. In 

 its upper part this valley has an east-west direction, but it soon takes 

 on the characteristic north-west and south-east orientation, and finally turns 

 and joins the other branch nearly at right angles. The dividing wall be- 

 tween it and the Lake Taylor Valley to the north, called the Oronoko Range, 

 has been partially broken down in several places. The most important of 

 these lies just opposite the head of Lake Sumner, where a low pass leads 

 from the northern to the southern valley of the Hurunui. On the southern 

 side of the pass is Lake Mason, tucked away in a tributary valley of the 

 South Branch. The country in this neighbourhood has been highly glaciated, 

 rochet moutonnees and smoothed surfaces forming characteristic features of 

 the landscape. Opposite the Lakes Station there is another saddle — some- 

 what high, it is true and the ridge has also been lowered in a line with 

 the Lake Taylor Valley leading directly to the North Branch south of Dog- 

 Hill, indicating an overflow in that direction. 



The partial dismemberment of this ridge affords a clue to the conditions 

 which obtained before dissection and isolation overtook the ridges to the 

 north-east. By noting its features it is possible to restore with reasonable 



