MACKIE — THE PAEALLEL ROADS OF GLE^' EOT. 
123 
at the commencement of the valley, since the rivers, which form the 
Roy, rise in mountain-torrents, forming a junction in the middle of 
the valley." A low hill of granite skirts the boundary between the 
source of the Spcy and the valley of the Roy. At the foot of this 
hill, in slightly elevated boggy plains, is found Loch Spey, the water 
from which, by a declivity for some time scarcely perceptible, runs 
eastward through Badenoch to fall into the Moray Firth. The 
western end of the boggy plain stretches for a few hundred yards be- 
yond the head of Loch Spey, and then descends by a sudden step 
into the upper valley of Glen Roy. This valley is of oval form, 
about four miles in length, and one or more in breadth, being 
bounded on opposite sides by very high mountains. Erom these 
descend two streams, which unite about the middle of the valley to 
form the Roy. From this junction the water flows witli a moderate 
velocity for the space of two miles, when the Glen suddenly contracts 
and terminates in a rocky hill of low elevation. The water, forcing 
its way for. some distance through a narrow pass between approach- 
ing rocks, enters a second glen — the lower Glen Roy. It is in this 
latter that the " roads " are chiefly seen ; nor on entering the upper 
from the lower glen would it be suspected that any similar appear- 
ances existed in it. A line however may be observed on the glen-side 
extending from the junction, which forms the Roy along the face 
of a low hill towards the elevation in which Loch Spey lies. "A 
careful examination of this line by spirit-level shows it to consist of 
a level narrow terrace, which, if prolonged eastward, would cut the 
perpendicular above Loch Spey, and if continued westward, would 
meet the summit of the flat rock that forms the division between the 
Roy. 
Fig. 2. — Section of Glen Roy, showing the contour and the levels of the three 
"parallel roads," 1, 2, 3. 
higher and lower Glen Roy." This summit is on a level with the 
uppermost of the lines in the lower glen, the terrace being in fact a 
prolongation of that line. No other terrace or line is found in the 
upper valley. . . . AVherever the natural rock conies to light, these 
