1863.] JAMIESON PAEALLEL ROADS OP GLEN EOY. 255 



other shells not ranging now so far sonth as Britain, show the assem- 

 blage to be of a decidedly more northern character than what now 

 haunts our coast. 



As the assemblage is a littoral one, I see no reason for doubting 

 that it belongs to the period represented by this 40-feet old coast- 

 line, probably the earlier part of that period. It is just the sort of 

 collection that might be expected at the depth of a few fathoms along 

 such a line of shore, were the sea somewhat colder than it is now. 



This bed of shells, I should think, must at all events be of later 

 date than the time when those large moraines were formed in Glen 

 Spean, which I have described in a former part of this paper ; for 

 the glacier of Glen Nevis, when at a corresponding state of develop- 

 ment (and probably the ice of the Great Glen itself), could not but 

 have extended past this spot, and would have consequently destroyed 

 this shell-bed, seeing that there was nothing to shelter it. 



The Scandinavian peninsula ought at that time to have had a 

 development of glaciers corresponding to its higher latitude and 

 elevation. Are we therefore to suppose that the elevated beds of 

 arctic shells and raised beaches described by Keilhau, Bravais, Lyell, 

 and others, occurring along many of the fiords from the Naze to the 

 North Cape — are we to suppose these to be posterior to the time of our 

 latest glaciers ? How otherwise could so many of them have escaped 

 destruction by the ice, those, for example, near Trondheim and on 

 the coast of Einmark ? If the glaciers that formed the large moraines 

 in Glen Spean were later than the chief submergence which covered 

 so much of Ireland and Britain, and left its arctic shells hundreds of 

 feet above our present coast-line, then surely an equivalent extension 

 of the ice in Scandinavia would have swept these Norwegian beaches 

 and shell-beds out of the positions where many of them occur. 

 Might we therefore synchronize some of these with our old 40-feet 

 coast-line of Argyleshire and its northern shells ? This would indi- 

 cate a greater elevation of the land to the eastward since the time 

 of that old beach. 



§ 4. Height and HorizontaUty of the Parallel Roads. 



We are indebted to Mr. Robert Chambers for the first good mea- 

 surement of the height of the lowest line. Mr. Joseph Mitchell, C.E., 

 of Inverness, at his request sent Mr. "William Paterson, one of his 

 surveyors, to carry a series of levellings up to it from Loch Lochy. 

 The result gave 847 feet above the sea for the height of the lowest 

 of the Parallel Roads of Glen Boy. The measurement seems to have 

 been taken at the western extremity of the line, and, so far as I can 

 learn, would seem to refer to high-water-mark, although this is 

 perhaps uncertain. The space between the lowest and the middle 

 line of Glen Roy was levelled by Dr. Macculloch and by Mr. D. 

 Stevenson and found by both to be 212 feet, thus giving (847+212) 

 1059 for the height of the middle line. The distance between the 

 middle and the uppermost line is, according to Macculloch, 82 feet, 

 and according to Mr. Stevenson, 80. Taking the mean of these, we 

 get (1059 + 81) 1140 feet above the sea for the highest Glen Roy line. 



