LAKES IN RELATION TO GEOLOGICAL FEATURES 509 
belt, has appropriated the highest tributaries of tliat valley. During 
the maximum glaciation the ice moved eastward from Moffatdale 
across the col. The level of St Mary's Loch has been raised by 
the deltas of the Kirkstead and Dryhope Burns. The Meggat delta 
has been carried far into the lake, and makes an appreciable feature 
on its floor. The Loch of the Lowes has been separated from St Mary's 
Loch by two converging deltas_, and the upper end of the former 
lake has been silted up for some distance up the river Yarrow. 
The valley above the loch is over-deepened relatively to its tributaries, 
so that the main river has great difficulty in distributing the material 
(deltas) brought down by the side streams. All these phenomena 
point to the action of ice in lowering the gradient of the valley 
above the foot of the loch. 
Salach Uidhre, na. — ^Minor rock-basin in granite and schist, studded with 
moraines, now covered by the reservoir of Loch Leven Aluminium 
Works. 
Sand. — Ponded by blown sand. 
Sandy. — In drift, artificially impounded. 
ScADAVAY. — Irregular rock-basin in Lewisian Gneiss, with numerous 
strike-basins and rocky islands strewn with glacial debris. 
ScAMADALE. — Valley rock-basin in Lorne volcanic plateau, partly along 
a line of fault. The loch is partly ponded by morainic and fluvio- 
glacial deposits, terraces of which occur at intervals along its sides 
and at the lower end, as if the material had been delivered from the 
front of the glacier which occupied the site of the loch at the time 
of their formation. 
ScARMCLATE. — Lying in boulder clay in a wide open valley in Caithness 
flagstones. 
ScASLAVAT. — Rock-basin in Lewisian Gneiss. 
Sealbhag. — Rock-basin in granulitic schists. 
Seasgain, an T-. — Rock-basin in Lewisian Gneiss, part of Loch 'Ic 
Colla. 
Seil. — Rock-basin in Lorne volcanic plateau. 
Seilich, an T-. — Rock-basin in Moine schists in Glen Tromie. 
Setter. — In drift resting on Old Red Sandstone. 
Sgamhain. — Rock-basin in Moine schists, the lower end of which has been 
silted up by the alluvium of AUt Coire Crubaidh, through which the 
river Carron winds till it reaches the head of the rock g-org-e at 
Glencarron. The rock-basin is still further filled with morainic and 
delta material along its sides and at its head. 
Sheallag, na. — Simple valley rock-basin in Lewisian Gneiss, which has 
been silted up for a mile or two at its head by morainic and fluvio- 
glacial materials and alluvium. 
Shiel. — Rock-basin in schists. Its characteristic straight feature suffsrests 
that its long axis coincides with a line of fault. Like most of the 
western fresh-water lochs, it lies in a deep valley open at both ends, 
