CH. Il] THE OCEANOGRAPHY OF THE NORTH-WESTERN OCEAN 31 



depths. It is here that we find the extreme western boundary 

 of the British submarine plateau. Out west about 200 nautical 

 miles distant from the centre of Scotland is the Rockall Bank, an 

 elevation of the bed of the Atlantic which rises up to about 200 

 metres from the surface. Between this and the British Islands 

 there is a tongue of deep water which extends up to the latitude 

 of Cape Wrath. The 2000-contour line of the Atlantic basin 

 curves round to the south and west of the Eockall Bank and 

 reaches to within about 15° S. from Iceland, 



If we look again at the hydrographic chart we find that an 

 extension of the continental shelf traverses the whole bed of the 

 north Atlantic in a north-westerly direction and connects the 

 British plateau with the coast of Greenland. Upon this are 

 situated the Faeroe Islands and Iceland, and round these and off 

 the south-west coast of Greenland are extensive " banks " or areas 

 of shallow water. Between Iceland and Greenland is a wide 

 extent of shallow sea ; between Iceland and the Faeroes is a wide 

 channel with an average depth of about 400 metres ; and between 

 the Faeroes and the British plateau is a comparatively narrow 

 tongue of deep water — over 1000 metres in depth — which is the 

 Faeroe Channel. In latitude 60° N. a narrow ridge connects the 

 British and Faeroese plateaux. This elevation of the ocean bed is 

 only a few miles broad, and over it the sea has an average depth 

 of about 500 metres. It is the well-known Wyville-Thomson 

 Ridge. 



Thus a series of submarine elevations join the continent of 

 Europe with the island of Greenland and separates the ocean into 

 two basins, those of the North Atlantic, and the Norwegian Sea. 

 On each side of the Wyville-Thomson Ridge the sea bed sinks 

 down rapidly to depths of over 1000 metres. To the south of the 

 ridge the sea slopes rather gradually down into the depression 

 between the Rockall Plateau and the coasts of Ireland and 

 Scotland. North of the ridge the sea bed slopes much more 

 steeply down into the Faeroe Channel and then into the Norwegian 

 basin. We shall see the significance of this disposition of the 

 ocean bed later on. 



It is on this shallow portion of the sea bed, practically in the 

 sea within the 200-metre line, that deep-sea fishing is carried on. 



