OF THE PARALLEL ROADS OF LOCHABER. 
717 
The great beds of rolled pebbles at the junction of the Lochy and Loch Linnhe, and 
extending thence to Gavilochy where they reach a height of 100 feet, alone have com¬ 
pletely the appearance of the wear and levelling caused by long-continued marine action. 
§ 15. Irregularities in the Levels of the “Roads.” 
The “roads” have always been spoken of as though they were, and to all appear¬ 
ances when standing on them they look to be, so perfectly horizontal that not until 
the foregoing pages were written was I led to question the point. The excellent 
1-inch maps of the Ordnance Survey, shaded or with contour lines, are so complete 
and convenient, that I had not thought it necessary to use the 6-inch maps. On 
recently referring to these latter, I unexpectedly find that the figures there given of 
the height of the “ roads ” at different places show differencesof level, which though 
comparatively small, are nevertheless sufficient in number and in frequency as to be 
incompatible with water-levels formed by the shore-lines of either a sea or a lake. 
Instead of a perfectly horizontal line, the “ roads ” are really slightly waved, the 
difference between the highest and the lowest points being, in the four “'roads,” taken 
in descending order, 15, 11, 15, and 12 feet; and it is to be remarked that, wdiile the 
level of the higher three “ roads ” is in most instances below that of the several cols, 
that of the lower “ road ” is in all instances above it. These differences are shown in 
the following table :— 
“ Road.” 
Height of col. 
Extreme differences of 
level between the cols 
and the “ roads.” 
Total difference 
in the level of 
the “ roads.” 
feet. 
feet. 
feet. 
feet. 
Ho. 1. Glen Gluoy. 
1172 
+ 1 
-14 
15 
,, 2. Glen Roy. 
1151 
+ 4 
— 7 
11 
,, 3. Glen Roy. 
1075 
+ 2 
-13 
15 
,, 4. Glen Roy f 
qaq 
/ +14 
+ 2 
12 
„ „ Glen Spean / 
1 +10 
+ 2 
8 
The variations of level form separate curves for each “road,” and do not constitute 
one common to all, so that they cannot be referred to subsequent movements of the 
ground, as these would have affected all the “ roads ” in the same degree. Besides this 
want of correspondence between the curves on the same hill side, there is a similar 
want of correspondence in the levels of the “roads” on the opposite sides of the 
valley. The character of these variations, and the relation of the several curves with 
a horizontal plane are shown in the following diagram (fig. 24) of the curves formed by 
a point taken in the centre of the “ roads ” on the west side of Glen Roy from above 
Achavady to near Dalriach, a distance of 4 miles. 
* The lowest and highest level of each “road” is given by Sir H. James, but without comment. He 
adopted Mr. Jamieson’s views— Op. tit., p. 2, 
