654 D. MILNE HOME ON THE PARALLEL ROADS OF LOCHABER. 
question, I may refer, in confirmation of the foregoing statements, to the 
testimony of Professor Nicon of Aberdeen, and the more so that he does not 
agree with me in my way of solving the problem. He says— 
“The detritus has not come down Loch Treig, as might at first sight be imagined, but from 
the Corry Laire, to the west; and has then been swept eastward by tidal currents, and even up 
into Loch Treig, on which it abuts, with a bold, almost vertical end. In many other places in 
this part of Glen Spean, there is similar evidence of a current from the west flowing up the 
valley.” —(“ Lond. Geol. Socy.” 21st May 1869, p. 288.) 
Higher up Glen Spean (as at Carbeg and Moy) there are several places 
where smoothed rock surfaces occur, sloping towards the west, with numerous 
parallel strize, running at one place W.3N.; at another, W. by S. 
There is, on the north side of the road, a mass of hard granite rock, rough 
on its east side, ground down and beautifully smoothed on its west side. 
At the Rough Burn there is a rock on the north side of the road, with a 
smoothed surface, dipping W.N.W., at an angle of 22°. Striz run obliquely 
across its face from W. by S. 
On the hill north-east of Rough Burn, 1600 feet above the sea, the rocks are 
smoothed on north-west sides, and are rough on opposite sides. There are 
quartz nodules in the rocks about 8 inches square, which are smoothed only on 
their west sides. 
All these facts tend to show a movement up Glen Spean, and not down 
from Loch Treig. 
Mr Jamieson, whilst he thinks he saw evidence that ice had passed down 
the Spean valley in its lower part, admits that in the upper part of Glen Spean 
Valley it is 
“ The west side of the rocky masses that has sustained most abrasion. Far away, even to the 
end of Loch Laggan, I traced the same appearances. Beyond the Pass of Makoul the low 
rocky eminences show evident traces of the passage of ice, going out towards the valley of the 
Spey.’ —(“ Lond. Geol. Socy. Journal,” 26th February 1862, p. 173.) 
The places before referred to of rocks ground and striated in Glen Spean, 
are along the whole course of the valley near the bottom. But higher up on its 
sides similar appearances exist. 
Thus Craig Dhu, on the north side of Glen Spean, near the foot of the 
valley, reaches to a height of 2161 feet above the sea. On the west and south 
aspects of the hill, I found the rocks bared and smoothed to a height of about 
1800 feet. The rocks on north aspects of the hill were rough. At two 
places, strize were observed by me, and their direction in both cases was W. by 
N. At the part of the hill next Glen Glaster, the rocks were smooth on the 
west side; rough on the east. There was a large surface of rock, dipping at 

