D. MILNE HOME ON THE PARALLEL ROADS OF LOCHABER. 628 
supposed outlet of the lake of No. 4 shelf, presents the appearance of an ancient 
river course, a flat passage of seventy feet wide, confined by wall-like rocks, 
which seem water worn” (p. 112), and this statement is actually accompanied by 
a woodcut representing this ancient river course. 
No doubt he only says that this Pass presents the appearance of an ancient 
river course. But he does not state how the appearance could be explained on 
any other principle than as the outlet of a lake. 
Professor Nicot, as I have already said, expresses an opinion that at none 
of the cols is “ there the slightest trace of an ancient river,” adding, that “there 
are indications of the passage of water, as through a narrow sea strait.” 
But the substitution of ‘a narrow sea strait” for a “river” is impossible, if 
the levelling by the Ordnance Surveyors is to be trusted, proving that the water 
in Glen Gluoy stood twelve feet higher than the water in Glen Roy, these two 
glens being connected by the passage referred to. 
2. Another difficulty with which Mr Darwin and his followers have to 
contend is suggested by the flatness of the ground which forms the shelves. 
On the sea-shore, where the tide rises and falls, the materials which collect 
on the beach undergo an action impossible in a lake. The beach must slope 
more or less from high water towards low water mark. But in the Lochaber 
shelves there is hardly any slope. RosBert CHAMBERS in his book (p. 98), gives a — 
woodcut, which shows the flatness of the shelves. (See also fig. 17, p. 51 hereof.) 
3. There is another feature which distinguishes the “ Parallel Roads” from 
sea-beaches. There are ancient sea-beaches along our coasts at eleven, twenty- 
five, and forty feet above the sea, not to speak of others at higher levels. These 
old “Sea Margins,” as CHAMBERS called them, even the lowest and most recent, 
are faintly impressed on the land. But if the Parallel Roads are sea 
beaches, how much more ancient must they be, if height above the sea is 
any measure of antiquity; and therefore, how much less distinct and less 
continuous ought they to be? Now, what is the fact? Undoubtedly, these 
“ Parallel Roads,” at heights exceeding 1000 feet above the sea, are much more 
distinct, continuous, and perfect, than any ancient sea-margins, even the lowest 
and most recent, which can any where be pointed out. 
4. But whilst I cannot accept Mr Darwin’s explanation of the Parallel 
Roads, I am free to admit that there are other markings on the hills of 
Lochaber which may possibly be ascribed to the sea. 
RosBeRT CHAMBERS in his book was the first to indicate certain lines more 
or less horizontal on Ben Chlinaig, and also on Craig Dhu. He thought that 
some of those corresponded in level on the opposite sides of the valley, and on 
this ground he pronounced them to be “ancient sea-levels.” 
That such lines exist, I can vouch for, having viewed them from various dis- 
tant points, and having measured the heights of several. 
VOL, XXVII. PART IV. 8B 
