W. Travers.—On Extinct Glaciers in the South Island. 301 
indicating, as they do in all the existing lakes, the direction of the most 
prevalent winds, and usually running across the valleys in which the lakes are 
situated. 
The moraine above referred to is about 24 miles below the main source of - 
the river, and the lake which succeeded the ice could not have been less than 
14 miles in length in the principal valley, with a branch at least five miles 
long in the tributary valley of the Ada. Of course it is impossible to deter- 
mine the actual depth of the moraine deposit at its upper face, but even 
assuming it not to exceed 150 feet below the lake mar, gin, we have an area of 
19 miles in length and a mile in width, with an average depth of 60 feet, 
which has been filled with river alluvium (independently of the immense 
quantity of matter which must at the same time have been carried below the 
moraine) within the period which the river has occupied in cutting down the 
comparatively loose material of this dam, to a depth of 35 feet only. 
It may, in view of such a fact, appear remarkable that the beds of the 
lakes on the northern side of the Spencer Mountains—which present on that 
side precisely similar conditions—should not also have been filled up; but 
1 attribute the rapid accumulation of alluvium in the case of the Dillon Valley 
to the facts that the mountains bounding it are much steeper, are composed of 
more easily disintegrated rock, are in their upper parts very bare of vegetation, 
and therefore exposed to the alternate action of frost and heat, and moreover 
present in many places, for thousands of feet in height and for miles in length, 
little else than continuous slopes of broken stone ; whilst those on the 
opposite side of the range are in a great measure densely wooded, and are 
chiefly composed of hard, crystalline rocks. I ought, however, to state that 
in assuming the moraine of the Dillon glacier to have a depth of only 150 feet 
below the lake margin above referred to, and in further assuming that the bed 
of the valley rises gradually from that depth to 0', I am doing so without any 
ascertained facts. 
lam not aware whether any measurements have been made in order to 
ascertain the depth of any of the lakes between the Spencer and Mount Cook 
ranges, with reference to the fall of the rivers flowing from them below the 
lines of their moraine dams ; but the depth of Lakes Arthur and Howick, on 
the northern side of the Spencer Mountains, is very great as compared with 
the apparent depth of the bed of the valley of the Buller ; whilst that of some 
of the larger lakes in the Otago Province, and ыу of the Wakatipu, 
exceeds 1,100 feet, their ES indeed, extending below the present level of 
the sea. 
From a consideration of these facts, and of others which I have not thought 
it necessary to mention in so general a sketch, I think we are justified in 
concluding that these extinct glaciers originated duri ing an upheaval of the 
