of Edinburgh, Session 1881 - 82 . 
639 
ward extending fishing-banks, and on the S.E. and S. by the Shet- 
land and Orkney Islands, the shores of Caithness and Sutherland, 
and the Hebrides. 
The Faroe Islands are composed of basaltic rocks, while the 
north of Scotland, and the Scottish Islands, are chiefly made up 
of Laurentian gneiss, Silurian, and Devonian rocks. 
The average width of the Faroe Channel, throughout its more defined 
and restricted portion, that is to say, between the 100 fathom line of 
soundings off the coast of Scotland and the Scottish Islands, and 
that of the Faroe plateau, is between 80 and 90 miles, and the maxi- 
mum depth rather more than 700 fathoms. 
At the south-westerly end the depth increases gradually to the 
mean depth of the “ Cable Plateau ” of the North Atlantic, and to- 
wards its north-easterly extension it deepens gradually to the lowest 
bed of the Arctic Ocean. 
Up to the time of the recent investigations the bottom was 
regarded as irregular, as the soundings seemed to indicate one or 
two dome-like elevations, rising towards the centre of the trough, 
to within 200 fathoms of the surface. 
The Faroe Channel has acquired special interest, because, so far 
as England is concerned, it is the region where systematic deep-sea 
investigations were first carried on. 
One of the most interesting results of the investigations of the 
“ Lightning” and “Porcupine” expeditions under Dr. Carpenter, 
Professor Wyville Thomson, and Mr. Gwyn Jeffreys in 1868-69, 
was the discovery in the deeper water of the Faroe Channel of 
contiguous areas, having widely different temperature conditions. 
This phenomenon is thus described by Dr. Carpenter : — “ Among 
the most important results of the i Lightning ’ expedition was the 
discovery of the fact that two very different submarine climates exist 
in the deep channel (from 500 to 600 fathoms) lying E.N.E. and 
W.S.W. between the north of Scotland and the Faroe banks; a 
minimum temperature of 32° being registered in some parts of this 
channel, whilst in other parts of it, at the same depths, and with the 
same surface temperature (never varying much from 52°) the minimum 
temperature registered was never lower than 46°, thus showing a 
difference of at least 14° ” ( Proc . Roy. Soc ., 1869, p. 453). 
Dr. Carpenter calls the regions indicated above the “ cold ” and 
