PARALLEL ROADS OF LOCHABER. 99 
On Plate XIV., there is a rough sketch (from memory) of the range of 
hills, looking at them from the eastward. The mouth of Corry N’Eoin is on 
the extreme left, a part of Aonach Mor (rocky hill) is D, on the extreme right. 
The red patches marked A’ to A?’ indicate flats, which being on a level with 
Shelf 4, I consider to be remnants of it. F is the principal stream which flows 
out of the Corry upon the flat meadow land E. Bis a projecting rock. Cisa 
bank of detritus, cut through by the stream G, and forms a projecting bank. 
On this detrital projection, there is no trace of Shelf 4. I therefore infer 
that the lake had not reached so far north. But, undoubtedly, there are traces 
of the lake in the mouth of the Corry, and on both sides of it, to the south- 
east of the above-mentioned detrital projection, as shown by the red patches.* 
A line drawn from this projection across Unachan Moor to Teandrish (see 
line KL on Plate XIII.) indicates what would naturally be the line of blockage, 
being at right angles to the central axis of Glen Spean. — 
Unachan Moor reaches now to a height of 613 feet above the sea, which is 
only 243 feet below the level of Shelf 4; and on various parts of the moor 
there are unmistakable signs of great erosion. 
The moor consists, as Dr CHAMBERS long ago stated, of an enormous mass 
of soft materials, chiefly gravel and sandy mud; so that denudation is quite 
intelligible. 
There are powerful mountain torrents from the steep hills here, which 
afforded ample means of erosion at each end of the blockage. The stream 
now flowing through Corry N’Eoin seems at a former period to have flowed 
out upon the plain through a channel more to the west, in which case it would 
have had a greater effect in removing the blockage. 
IV. Supposition that Glaciers may have been formed in Corry N’Eoin and 
Loch Treig. 
1. In my previous Memoir, I pointed out that, even had there been 
glaciers in these glens, the levels of the country and the contours of the hills 
would not have admitted of their flowing to the places in Glen Roy and Glen 
Collarig, where the blockages were required. 
The site of the Glen Spean blockage (between the north side of Corry 
N’Eoin and Teandrish) might have been occupied by a glacier from Corry 
N’Eoin, ¢f it were possible that a tongue of ice, five miles long, could have pro- 
truded from that small Corry, and been pressed against the hills at Teandrish 
so tightly as to dam back Loch Spean. 
2. But the fatal objection to the whole of this glacier theory is, that neither 
in Corry N’Eoin nor in Loch Treig, could there have beena glacier at the time 
when these lakes which formed the “ Parallel Roads” existed; for, on an 
* See reference to this Corry at pages 631 and 632 of former Memoir. 
