646 D. MILNE HOME ON THE PARALLEL ROADS OF LOCHABER. 
There is another difference between the two cases, favorable to the theory 
of floating ice. The detritus covering the sea-bottom, would afford to floating 
ice means of smoothing and scoring. But as the ice cake period is supposed 
to have preceded the detritus period, the land ice in passing over the rocks 
would have no such help. 
There are other circumstances which favour the idea of floating ice, suggested 
by some observations by Mr. Jamieson himself. 
He mentions having noticed, at considerable heights both at Loch Treig 
(vol. xviii. p. 172) and in Glen Roy (p. 177) striz running horizontally, on 
the rock jfaces.* I made a similar observation on Craig Dhu.t Mr JAmrEson 
also takes notice of the circumstance that on Craig Dhu, ‘the largest and most 
angular blocks are more numerous high upon the very brow of the hill, at a 
level of from 130 to 400 feet from the top, than they are farther down” 
(vol. xviii. p. 175). 
Similar observations were made by Mr Darwin and others. 
There is another feature in these Glens, pointing to floating ice. I allude 
to the discovery of exceptional lines of detritus, running nearly horizontal on the 
sides of Craig Dhu and Ben Chlinaig, where they face each other, and also on 
the sides of Glen Roy. These lines are at different heights, from 1200 to 
1700 feet above the sea. Mr JAmteson says of the Ben Chlinaig lines, “I 
ascertained that these short lines were neither quite horizontal nor perfectly 
parallel. I therefore think they “have arisen from some other cause than what 
formed the Parallel Roads.” 
Mr JoLiy concurs with Mr JAMIESON in stating “that these lines are not 
absolutely horizontal. They rise and fall in short distances on the hill side, 
gradually but perceptibly” (MSS. p. 15). 
Mr Jouty adds, that these banks “form a rounded curve like that of a 
mound or ridge, laid upon the hill. They resemble “kaims” in the outline, 
and present the appearance which ridges of detritus would have if deposited 
on a slope. Between them and the hill, there exists a hollow, often deep 
enough to form a kind of valley. This moundy character is well seen on all 
the lines on Ben Chlinaig, and Craig Dhu” (MSS. p. 18). 
Mr Jouty is decidedly of opinion that these banks are moraines; Mr 
JAMIESON had previously indicated an inclination towards the same view. 
Rogsert CHALMERS felt assured that they were sea-beaches, and entirely of the 
same class as the Parallel Roads. 
I have the misfortune to differ from all these views. I think that Mr 
* See p. 41 hereof. 
+ See p. 640 hereof. For an interesting account of the agency of Pack Ice, not only in transport- 
ing boulders, but in making “ horizontal grooves and scratches” on cliffs of rock, see a paper by 
Professor Joun Miunz, F.C. S, in the Geolog gical Magazine for September 1876. 

