Tuomson.—Glacial Action in Otago. 327 
snows of the mountains in this district show their influence in the last month 
of the year, by melting and flooding the torrents, so ) may the mountain glaciers be 
said to havea marked epoch, special to themselves, at the end of the glacial age, 
which epoch is recorded by the moraines now extending round or at their ancient 
lower termini. Speaking from recollection, and going back seventeen years, 
I was struck with the immense hillocks of confused rubble, earth, and boulders 
extending round the southern shores of Ohau to Pukaki, and rising near 
300 feet in elevation. There was, now, no apparent cause for this until we 
turned our eyes to view the receding glaciers, to be descried in the distance, 
high up in the mountains. So, at the southern end of Lake Wakatipu, 
similar phenomena are to be observed, leading to the same conclusions. The 
Francis Joseph Glacier, on the West Coast, extends down to 700 feet from the 
sea level, and those on the eastern slopes of the Southern Alps to 2,774 feet. 
Thus, in a particular valley on the West Coast, the glacial age may be said to 
be only 700 feet perpendicularly distant ; while, horizontally, it is, as stated 
before, 23 degrees of latitude southward. On comparing the measurements, it 
will be at once noted that those of the valleys of the Waitaki and the Clutha 
are much modified ; this is owing to the Pukaki and Wanaka Lakes forming 
portions of the valleys of the Waitaki and Molyneux. The cause of this 
exception has been ascribed, by one class of observers, to the scooping effects 
of mountain glaciers, while, by another class, it has been ascribed to the 
original depressions when the mountains and valleys assumed the geological 
arrangement now existing. As much has been advanced on both sides of the 
question, I will content myself by suggesting that we will not be doing much 
violence to either theory by giving both of them weight in modelling the surface 
of our valleys to their present form. Thus, I may ask those gentlemen who 
adhere to this lake-scooping action alone, why the Ahuriri had not a lake as 
well as its neighbour the Ohau; the Shotover and Arrow as well as the 
Dart and Rees; and the Oreti as well as its neighbour the Mararora ; all 
flowing out of glacial mountains and under similar conditions? May we not 
give weight to the axiom, that where there are high elevations, so must there 
be low depressions ; and where one varies in height, so will tlie other in depth? 
Thus, may not the valley of the Wanaka have been originally lower than that 
of the Matukituki, as their respective passes are lower; and so, while the 
valley of one is filled with water, the other is filled with the bed rock, overlain 
with sand and shingle. 
Then, to revert to the influence that glaciers of probably 3,000 and more 
feet in thickness would have in scooping action, or modification of shores and 
bottom, we must consider the nature of the rocks acted on. 
. The resisting power of the hard schists, being as hard as granite, that line 
the Wakatipu Lake, varies from 5,5001bs. to 11,0001bs. per square inch. Now, 
