90 Transactions. 
Авт. 6.—Note on the Hanging Valleys of the Upper Rangitata Valley. 
Ву В. Spxicut, M.Sc., F.G.S., F.N.Z.Inst., Curator of the Canterbury 
Museum. 
[Read before the Philosophical Institute of Canterbury, 7th September, 1921; received by 
Edi 
t 
ditor, 31st December, 1921 ; issued separately, 1st February, 1923.] 
Plates 8, 9. 
of ice as an erosive agent, a question concerning which there are varie 
opinions. Authorities like Davis (1909), Gilbert (1904), and Penck credit 
running water; and these opinions are supported in America by Fairchild 
(1905), Russell (1905), and others. 
According to the first group of authorities, hanging valleys are due to 
the greater activity of the ice occupying the main valley in comparison 
with that in the tributaries, this activity being attributable to the greater 
volume and thickness of the ice in the former, the result being that the floor 
of the main valley is overdeepened as compared with that of its tributary, 
so that when the ice-flood has subsided the tributary river enters the main 
valley with discordant grade. De Martonne (1910) attributes the formation 
of hanging valleys chiefly to lateral sapping, though he admits a certain 
amount of overdeepening, but not on the bars (verrous) across the main 
valley, near which hanging valleys are also found. Certain members of 
the second group of authorities regard glaciers in the tributary valleys a$ 
protecting their floors, while the rivers of the main valley lower their 
bottoms by normal stream erosion. 
A consideration of the satisfactory nature of one or other of these 
explanations arose during two visits to the upper Rangitata in company 
with three of my colleagues, when we were fortunate in having ample 
opportunity of observing more perfect suites of such valleys than it had 
been my fortune to see previously. 
‚ One group of these occurs on the left (eastern) bank of the Havelock 
_ River, on the western slope of the Cloudy Peak Range, a spur running from 
