GLACIATION OF THE SHETLAND ISLES. 805 
the hills north of Magnusetter Yoe, in Northmayine, we counted 
about twenty small lochs in the heart of the diorite-area. 
On the promontory of Lunnasting they likewise occur in great 
numbers, varying in size from basin-shaped hollows to lochs more 
than a mile in length. Their long axes coincide with the strike of 
the underlying gneiss; but, owing to the scooping-agent haying 
crossed the lines of stratification nearly at right angles, their out- 
lines are very irregular. Similar strike-basins are to be found on 
the promontory between Vidlon and Dourye Voes; and from the 
manner in which they are hemmed in by roches moutonnées on every 
side, it is impossible to resist the conclusion that they are due to 
ice-action. ‘lhe lochs now referred to must have originated during 
the primary glaciation, because there is no evidence that the later 
glaciers ever overflowed the headlands of Lunnasting. 
The voes or sea-lochs are among the most interesting features of 
the Shetland Isles ; and the question of their origin is not free from 
difficulty. Flowing, as they do, for miles into the heart of the country, 
it sometimes happens that only a narrow isthmus is left to prevent 
the waters of opposite shores from uniting. Yell is nearly bisected 
by the Whalefirth and Reafirth Voes; and a submergence of a few 
feet would separate Northmavine from the Mainland, and allow the 
waters of Sulem Voe to flow westward into St. Magnus Bay. 
Sometimes the voes are flanked by gentle slopes of Boulder-clay, as 
we have frequently indicated; at other times they are bounded by 
steep walls of rocks, as in the well-known Roeness Voe. Many of 
the most characteristic sea-lochs lie along the line of strike of the 
metamorphic rocks, of which the Weesdale, Stromness, Whiteness, 
Dales and Laxfirth Voes may be cited as the best examples; but 
there are others which have no connexion with the lines of stra- 
tification. As a rule, they are found to merge into narrow valleys 
draining the high grounds, the width of the voes being in direct 
proportion to the size of the valleys. This relationship would seem 
to indicate that these narrow fiords are submerged land-valleys 
which existed long before glacial times. In the course of our tra- 
verses in Shetland, we heard frequent testimony pointing to the 
conclusion that the ridge-shaped contour which is so prevalent in 
the Mainland, Yell and Unst, likewise extends along the sea-bottom ; 
and it is highly probable that it isdue to the same cause in both 
cases. If this be true, then these fjord-valleys may have been 
carved out by the ordinary agents of denudation when the floor of 
the sea which now surrounds Shetland formed dry land. Both 
in Scotland and along the east coast of England the evidence de- 
rived from buried river-channels would lead us to believe that these 
countries stood at a higher level in preglacial times than they do 
now; and we may well believe that Shetland shared in the same 
continental conditions. ‘The absence of shells in the Boulder-clay 
seems to strengthen this conclusion. 
At any rate the agents of denudation would be guided in their 
operation in a large measure by the strike of the metamorphic 
rocks; and if there was a wide area of land round what now 
constitutes the Shetland archipelago, they would accomplish greater 
