in Europe and North America. 345 
were shrinking into the mountain-valleys. 
Finally, if this be true, I find it difficult to believe that the 
of Britain and Ireland, the Black Forest, and the Vosges. 
_ Say has published an article ‘On the Excavation of the Valleys 
of the Alps,” called out by some discussion of his views, in 
which he concludes as follows:—Ebs. 
_ “No better proof could be required that in great part the 
Valleys of the Alps were approximately as deep before the gla- 
_ Mal epoch as they are at present; and I believe, with the Italian 
Geologists, that all that the glaciers as a whole effected was only 
slightly to deepen these valleys and materially to modify their 
_ 8eneral outlines, and, further (a theory I am alone responsi 
for), to deepen them in parts more considerably when, from va- 
_ Nous causes, the grinding power of the ice was unusually pow- 
erful, especially where, as in the lowlands of Switzerland, the 
_ “l0cene strata are comparatively soft. But for details on this 
_ Point I must refer to my memoir in the Journal of the Geologi- 
eal Society.” 
* It has been Si ; igi f the 
suggested to me by Dr. Sibson that the prodigious waste of th 
Alps by the gradual disintegration and diminution of the upper snow-fields, wit- 
i m 
_ eded to lessen: the glaciers. This. is true; but, as he also. believes it i mt of 
_ .S6i enough to account for the shrinking of t nto the higher valleys w it 
“ is now alone found, ° 
