Vol. 58.] VALLEYS IN THE ALPS AND HIMALAYAS, (Si 
with overlapping spurs which he had described, had ascertained that 
the partial destruction of the spurs was due to ice, and not to water. 
In the Lake District, he (the speaker) believed that the hanging 
valleys were often due to differences in rock-structure, especially to 
the existence of gigantic brecciation along the main valleys, though 
many other structures produced their effects. He wished to 
emphasize the importance of carefully studying each case (as had 
been done by the Authors), for many valleys which were not really 
‘hanging valleys’ appeared, at first sight, to simulate them; and, 
indeed, he believed that detailed study of various different districts 
was necessary before the intricate question of the formation of these 
valleys could be finally solved. 
Mr, MacxinpEr agreed with the previous speaker that we should 
first study special cases, and then generalize. But if we accept 
the general idea of a difference of erosive power as the cause of the 
contrast between the main and the ‘hanging’ valleys, then the 
hanging valleys should diminish in scale towards the upper part of 
the main valley, unless indeed there should be a hanging valley at 
the head of the main valley. Perhaps this might be so in some 
cases. 
Mr. Lamprtues remarked that, whatever objection might be 
taken to the methods and conclusions of Prof. Davis, his work, at 
any rate, deserved credit for having stimulated fresh investigation 
on alj sides. He agreed with Mr. Marr that hanging valleys 
might be formed in different ways, and therefore required separate 
study. In the examples best known to him, the explanation 
given by the present Authors, that the trunk-valleys had been 
deepened mainly by stream-erosion, was fully adequate. At the 
same time, it must not be forgotten that there were proofs that the 
land-surface had sometimes been pared down by ice-action, though 
perhaps not so much in confined valleys as in more open ground. 
Gen. McManovy, as an illustration of the small power of erosion 
possessed by a glacier, instanced a case in the Upper Spiti Valley, 
in the Central Himalayas, at an elevation of 14,000 feet, of a small 
spur composed of thin splintery slates, running into the valley at 
right angles to the course of a glacier, which once filled the valley. 
The crest of this thin ridge was rounded, beautifully polished, 
and grooved and striated by ice-action, showing that the glacier 
bad ridden over it, in its passage downward, but had been unable 
to remove this barrier. 
Prof. Boryey, in replying, remarked that he had avoided appeal- 
ing to the effect of uplift (though he was quite prepared to admit 
that it might have occurred), because he wished to see the results 
of less hypothetical causes. He fully endorsed Prof. Garwood’s 
remarks about the Maloja and other parts of the Engadine. The 
President was quite right in attributing the explanation of the struc- 
ture of the Inn Valley to Prof. Heim. In fact, it had been indepen- 
dently published by him and by the speaker, but the former had 
priority. He thought that the President had a little misunderstood 
(probably owing to his remarks about the Oberland) what he had 
