1905-6.] Formation of certain Lakes in the Highlands. 115 
Henry H. Howorth gives this quotation from Lamplugh : “ This is 
the first glacier I have visited, and I brought away the impression 
that on the whole it was easier to give explanations of glacial 
phenomena before I had seen ice ! ” I am not of the same opinion, 
and I am sure that we can learn from the study of the present 
glaciers that there is a lateral action of the glacier against the walls 
of the surrounding cliffs, an erosive action which is small, I must 
say, but which cannot be denied. Now, when talking about the 
tremendous glaciers of the Great Ice Age which in Switzerland 
reached a thickness of 3000 feet, we are obliged to say that if the 
present glaciers, which are insignificant in comparison, have an 
erosive action, a fortiori those of the Great Ice Age must have 
been able to erode rocks. 
I have given in this short note facts of observation collected 
during my climbs in the Alps and during my geological studies in 
the field. I desire to thank Mr James Chumley for assisting me 
in preparing this paper for the press. 
Challenger Office, 
Edinburgh, January 1906. 
( Issued separately April 16, 1906.) 
