690 PROF. T. G. BONNEY ON [ Nov. rgo02, 
37. AtpINE VALLEYS im Retation to Guactzrs. By Prof. T. 
G. Bonney, D.Sc., LL.D., F.R.S., F.G.S. (Read June 11th, 
1902.) 
[Prats XXXV—Secrions. | 
EviIpENTLy faith in the excavating power of glaciers will not become 
extinct in the lifetime of Prot. W. M. Davis, for he has recently 
credited them with the making of not only the Alpine lakes, but 
also no small part of the valleys." They have produced, in his 
opinion, similar effects in Central France also and in Norway. 
Into these countries, though I know both fairly well, I cannot 
follow him without making an undue demand on the Society’s 
patience, so I shall restrict myself to the Alps, and in doing this 
shall say very little about the Ticino Valley, which in Prof. Davis’s 
paper occupies a prominent position. That I pass over (although, 
as it happens, my own ideas on this subject assumed a more definite 
form during a stay in one of its ‘ hanging valleys’ four years ago) 
because I found that my friend and successor, Prof. Garwood, had 
devoted some time last summer to testing Prof. Davis’s hypotheses 
in the place of their nativity, and was no nearer being a convert 
than myself. So I have ceded that region to him, and select for 
my purpose one or two other districts with which I am not less 
familiar, and apparently more so than Prof. Davis, whose method 
of dealing with this intricate problem does not strike me as 
satisfactory: for, so far as 1 can discover, he did little more than 
travel through the Alps by one or two frequented routes.. But a 
problem of this kind cannot be solved without examining the upper 
as well as the lower parts of valleys, and contemplating the moun- 
tains from their peaks as well as from their bases. Under these 
circumstances, I think that we are entitled to demand facts and 
reasons in support of assertions, and to demur when we find the latter 
treated as valid foundations in the construction of an hypothesis. 
A thorough discussion of Prof. Davis’s paper would be tedious to 
the Society, for I should have to take it section by section, and . 
insert with tiresome iteration either a ‘not proven’ or a non 
sequitur, so 1 will restrict myself to one of his hypotheses, with 
which, in my opinion, his whole position stands or falls. A very 
common type in Alpine valleys, according to his observations, is 
represented in Pl. XXXV, fig. 3, no. I. The more open part above 
the dotted line AB he maintains to be pre-Glacial, and the narrower 
one below to be the work of glaciers in the Ice-Age.* The first of 
these positions I do not dispute, though I attach a rather different 
sense to the words ; the latter, I hope to show, cannot be harmonized 
with the facts. 
1 ¢@lacial Erosion in France, Switzerland, & Norway’ Proc. Boston Soc. 
Nat. Hist. vol. xxix (1900) pp. 273-322. 
2 For his arguments I must refer the reader to his paper, but I think that 
all familiar with the subject will easily infer them from my own. 
