THE PHYSICAL HISTORY OP THE NORWEGIAN PJORDS. 151 



had passed away entirely, though so evidently not to be confounded 

 with the former upheaval. 



Until I read your explanation of the shallowness of the 

 fjords, in many instances in their lower course, I was under the 

 impression tliat it was due to a great extent to glacial boulders 

 and detritus which did not reach the sea ; but you so plainly show 

 the manner in which the ice attained to prodigious thickness in 

 the upper portion of the fjords as to have eroded to a far greater 

 extent than further down, that no difficulty remains in one's mind, 

 and the entire obliteration of the submerged channels beyond the 

 present outlets of so many fjords into the North Sea (so far, at 

 least, as my Norwegian soundings show) seems to bo attributable 

 to icebergs breaking off from, the respective fjords at a remote 

 pei'iod, but in a very insignificant degree, in proportion, to the 

 action of the marine cui^rents to which I had fancied that they 

 owed their being filled in. 



Such is the apparent uniformity of breadth and depth of the 

 great channel skirting Norway in the North Sea, that it seems to 

 me improbable that icebergs should have been carried out to sea 

 westwards to such a vast extent as to have covered the floor of 

 the North Sea to any great thickness with boulders or detritus ; 

 but we shall never know further on this subject. 



Concurring with what Dr. Walker observed in his communica- 

 tion, I should greatly Avish to find you now extend your investiga- 

 tions to Iceland, but more especially to Grreenland and South 

 Finland. 



BoBBio Pellice, Turin. 



2Uh July, 1902. 



