THE FRESH- WATER LOCHS OF SCOTLAND. 239 
of the region, we prefer not to discuss its features in connection with 
the theory of the glacial origin of lake basins. 
Loclian Fada is a simple rock basin resting partly on Torridon 
Sandstone and partly on Lewisian gneiss. Along the greater part of 
its course it coincides with an old pre-Torridonian valley, trending in a 
west-north-west direction. At its eastern end it is bounded by the 
continuation of the Glen Fhasaigh fault, which brings down the 
Cambrian quartzite, Fucoid beds, Serpulite grit, limestone, and over- 
lying Archaean gneiss above the Glen Logan or Kishorn thrust-plane. 
The sudden deepening of the loch at its lower end is evidently related 
to this fault, because harder and more durable strata on the east side 
of this fault have been brought against the softer Torridon Sandstone 
to the west. It is important to note that the downthrow side of this 
fault is towards the east ; in other words, the eastern floor of Lochan 
Fada is not faulted down to the west. It is interesting to note that the 
deepest part of the basin, and the deepest sounding (248 feet), lie 
between Slioch and Ben Tarsuinn, where the erosion of the ice during 
the maximum glaciation would probably be greatest. 
Loch Garhliaig, which is situated to the north of Ben Slioch, is a 
small lake over a mile in length, and evidently a rock basin from the 
appearance of Lewisian gneiss at its exit, where it is drained by the 
Amhainn na Fuirneis. The soundings prove the existence of two 
basins separated by a ridge, the eastern one reaching a depth of 93 feet, 
and. the western 50 feet close to its outlet. This lake lies mainly along 
the junction of the Archaean rocks and Torridon Sandstone, the older 
rocks forming the greater part of the north shore, and the red sand- 
stone the larger part of the south margin. A tongue of Torridon 
breccia occupies a hollow in the Archaean rocks on the north shore, 
where it rests on a mass of hornblende-schist. This breccia appears in 
an island in the loch, which forms part of the ridge separating the two 
basins. The loch may therefore be regarded as a rock basin eroded by 
ice, mainly out of Torridon Sandstone along its line of junction with 
the Archaean floor. 
Loch Kernsary is very irregular in shape, and has four basins below 
the 50-feet level, the deepest sounding — 93 feet — being found near its 
north-west extremity. The Archaean gneiss forms part of its north-east 
shore, while the Torridonian rocks floor the remaining portions, save 
near the west limit of the north shore, where a boss of Lewisian gneiss 
projects through the Torridon Sandstone. As the Torridon sandstones 
and conglomerates dip at angles varying from 20° to 35° to the north- 
west, we may infer that those sediments are resting on a very uneven 
floor of gneiss. The bed of the lake, therefore, may here correspond 
with the pre-Torridonian surface, the softer Torridon Sandstone being 
more easily removed than the more durable gneiss. Stride pointing in 
a north-west direction are found round the lake, the trend of which is 
