186 GEOLOGY [CHAP. IX 



Letter 522 other valleys of Scotland, where I saw similar buttresses 

 at many levels ; 2nd, because the outlets of the supposed 

 lakes as already stated seem, from Mr. Milne's statements, too 

 much worn and too large ; 3rd, when the lake stood at the 

 three-quarters of a mile shelf the water from it must have 

 flowed over ice itself for a very long time, and kept at the 

 same exact level : certainly this shelf required a long time 

 for its formation ; 4th, I cannot believe a glacier would 

 have blocked up the short, very wide valley of Kilfinnin, the 

 Great Glen of Scotland also being very low there ; 5th, 

 the country at some places where Mr. Milne has described 

 terraces is not mountainous, and the number of ice-lakes 

 appears to me very improbable ; 6th, I do not believe any 

 lake could scoop the rocks so much as they are at the entrance 

 to Loch Treig or cut them off at the head of Upper Glen 

 Roy ; 7th, the very gradual dying away of the terraces at 

 the mouth of Glen Roy does not look like a barrier of any 

 kind ; 8th, I should have expected great terminal moraines 

 across the mouth of Glen Roy, Glen Collarig, and Glaster, 

 at least at the bottom of the valleys. Such, I feel pretty 

 sure, do not exist. 



I fear I must have wearied you with the length of this 

 letter, which I have not had time to arrange properly. I 

 could argue at great length against Mr. Milne's theory of 

 barriers of detritus, though I could help him in one way viz., 

 by the soundings which occur at the entrances of the deepest 

 fiords in T. del Fuego. I do not think he gives the smallest 

 satisfaction with respect to the successive and comparatively 

 sudden breakage of his many lakes. 



Well, I enjoyed my trip to Glen Roy very much, but it 

 was time thrown away. I heartily wish you would go there ; 

 it should be some one who knows glacier and iceberg action, 

 and sea action well. I wish the Queen would command you. 

 I had intended being in London to-morrow, but one of my 

 principal plagues will, I believe, stop me ; if I do I will 

 assuredly call on you. I have not yet read Mr. Milne on 

 Elevation, 1 so will keep his paper for a day or two. 



P.S. As you cannot want this letter, I wish you would 



1 "On a Remarkable Oscillation of the Sea, observed at Various 

 Places on the Coasts of Great Britain in the First Week of July, 1843." 

 Trans. R. Soc. Edinb., Vol. XV., p. 609, 1844. 



