THE FRESH- WATER LOCHS OF SCOTLAND. 
189 
direction of an old consequent valley traversing the Archaean plateau 
and the Torridonian and Cambrian strata north-west of Elphin. These 
lakes were evidently at one time connected, for an alluvial terrace 
stretches up the valley from the Fionn Loch to near Loch Veyatie. The 
height of the surface of the Fionn Loch is 357 feet above sea-level, and 
the height of the alluvial terrace is 379 feet, so that the lake has been 
lowered by about 20 feet. The long axis of this lake coincides generally 
with the strike of the original banding of the Archcean gneiss, which 
there dips to the south-west at angles varying from 20° to 30°. Several 
large intrusive dykes trend obliquely up the loch, and lines of newer 
shearing enter the lake on the north-west side, trending north-west. 
Indeed, these shear lines have evidently determined the arm of the 
lake that runs westwards beyond the point where the river Kirkaig 
drains this sheet of water. Though of irregular contour, the soundings 
show that it is a long narrow basin, the deepest sounding being 90 feet. 
In like manner, though Loch Veyatie is 4 miles long, the soundings 
show that it is a comparatively shallow basin, the deepest sounding 
being 126 feet north of Loch a’ Mhiotailt and near the foot of the 
loch. The long axis of this lake is oblique to the strike of the early 
foliation of the Archaean gneiss, and several large intrusive dykes enter 
the foot of the lake, the direction of which coincides with that axis. 
The upper part of the lake is floored partly by Cambrian and partly 
by Torridonian strata, the lofty mountain of. Cul Mor rising to a 
height of 2786 feet on the south side. The soundings show that there 
are three small basins, each over 100 feet in depth, two of which lie 
north-north-east of the great escarpment of Torridon Sandstone of Cul 
Mor, and the third near the foot, opposite an escarpment of Archaean 
gneiss which rises to a height of 200 feet above the level of the lake. 
Loch a’ Mhiotailt is an arm of Loch Veyatie, near the foot of the 
latter, and on its south side. The deepest sounding is 69 feet. The 
long arm of the lake has evidently been determined by faults which 
shift the outcrops of the intrusive dykes. 
T^och Gam flows into Loch Veyatie at its upper end, near Elphin. 
The western portion of this lake is floored by Archaean rocks, and the 
central and eastern portions by Torridonian and Cambrian strata. 
The soundings show that it is a comparatively shallow rock-basin. 
Much of the east part near Elphin is under 50 feet in depth, and the 
deepest soundings recorded at two localities further west are 122 feet. 
One of these localities is at the narrows, where the lake is floored by 
Cambrian quartzite, and the other about two-thirds of a mile from the 
head on the Archaean plateau. The soundings further show that near 
the head of the lake on the south-west side there is a narrow basin 
trending nearly west-north-west, enclosed by the 100-feet contour-line, 
the direction of which coincides with a line of pre-Torridonian shearing 
that has been traced for miles to the west-north-west into the Fionn 
