98 Transactions. 
(2.) The possibility of attributing hanging valleys to causes not demanding 
profound deepening of the main valley. 
(3.) The comparatively slight modification of many of the spurs reaching 
down into the main valley. Truncation and partial truncation are admitted, 
but this does not demand any abnormal change. 
(4.) The difficulty of restoring the preglacial stream-system if profound 
modification be granted, though the restoration is easy if the modification 
has been slight. This reason has certainly no great weight of itself, but 
taken in conjunction with others it is of some importance. 
(5.) The thickness and extent of the morainic deposits are not such as 
one would expect had the valleys been modified profoundly, this neces- " 
sitating the removal of an enormous volume of rock. In the Mackenzie 
country, near Lake Coleridge and the gorge of the Rakaia, in the valley 4 
of the Ashburton near Lake Heron and Hakatere, and at other places, the — 
morainie material is a veneer resting on older river-gravels, or on Tertiary ; 
and other beds, rather than a massive deposit. The area covered may be á 
NOTE. 
| A recent visit to the Wakatipu-Wanaka district has impressed me 
with the fact that local circumstances must be carefully considered when | 
valley of a preglacial stream- system, other hanging valleys must be 
eredited to causes which have no connection with this previous drainage. 
REFERENCES. 
Воххкү, T. G., 1893. Do Glaciers excavate ? Geog. Jour., vol. 1, pp. 481-! 
Davis, W. M., 1900. Glacial Erosion in France, Switzerland, and Norway, 
Soc. Nat. Hist., vol. 29, No. 14, pp. 273-322. 
— 1909. Glacial Erosion in North Wales, Quart. Jour. Geol. Soc., vol. 65, pp. 281-350. 
DE MARTOSNE, E., 1910. L'érosion glaciaire et la formation des vallées alpines, — 
99. 
Proc. Bost. 
pp. 74 
FREsHFIELD, D. W., 1888. Note on the Conservative Action of Glaciers, Proc. Коу. 
Geog. Soc., vol. 10, рр. 779-89. 
Garwoop, Ё. J., 1902. Hanging Valleys of the Alps and Himalayas, Quart. Jour. 
ie эс vol. n рр. 7903-14. 1, 365 2 
—— . Features of Alpine Scenery due to i i . Jour, VOR Te Д 
op. 810 98. p scenery due to Glacier Protection, Geog. 
GziKrE, JAMES, 1902. Earth Sculpture. 
= GILBERT, б. K., 1904. Alaska, vol. 3, Glaciers and Glaciation. 
, 1910. Die Täler der Schweizeralpen. | 
С., 1905. Hanging Valleys, Bull. Geol. Soc. Amer., vol. 16, pp. 75—90. 
ck, REvscH, Нбевом, and others have also been consulted. 
