22 CANON NORMAN THE CELTIC PROVINCE : 



whicli is not connected by lesser depths with adjacent land. 

 The chief apparent exceptions to this are three patches in 

 a line directly north of the Azores where lesser depths are 

 met with so that one sounding gives only 625 fathoms. But 

 even here the soundings taken have not been sufficient to exclude 

 the possibility of a continual line under 1,500 fathoms in con- 

 nection with the Azores. The bed of the whole of the North 

 Atlantic, with the exceptions which I have mentioned, is covered 

 by water at a depth of from 1,500 to 3,000 fathoms, but there 

 is only one sounding, and that on the western side of the 

 Atlantic, whicli gives so great a depth as 3,000 fathoms. The 

 general range is from 1,600 to 2,500 fathoms. 



Tracing now this 1,500-fathom line along the coast of Eui'ope, 

 we find that an enormous tract of ocean-bottom within this 

 depth exists south of Iceland and west of Scotland. On reaching 

 Ireland the area covered is of very much less extent. Here the 

 Continental Shelf extends westward of the Shannon, roughly 

 speaking, about 800 miles, with a depth rarely exceeding 250 

 fathoms. Then westward again, in a few miles, the Continent is 

 propped up by vast bvittresses, 5,000 or 6,000 feet in height, whicli 

 rise from the bed of the ocean. Such a precipice is at one spot 

 on the North Atlantic Chart represented by two soundings of 

 660 and 1,670 fathoms, the figures of which almost touch each 

 other on the chart. This Continental Shelf, which name has 

 been given to the submerged portions of the Continent, when 

 followed southwards becomes rapidly less extended, so that 

 from the Bay of Biscay southwards, for fully 2,000 miles along- 

 European and African coasts (beyond which it is not necessary 

 to go), the Continental Shelf down to 1,500 fathoms has an 

 average distance from land of only 60 or 80 miles. 



We argue, then, that the limit of the British fauna to the 

 west of our islands should be the base of the Continent at 

 1,500 fathoms. To the east, the mid-line between Continental 

 Europe and Grreat Britain must be taken as the boundary.* 



Northward, however, we meet with some peculiar circumstances ; 

 here to the east are the Shetland Islands, while westward lie the 

 Faroe Islands. Between these groups of islands there is a deep 

 trough known as the Faroe Channel. This trough has a depth 

 of 500 to 600 fathoms. Directly south of it the ocean-bed 

 rises more than 200 fathoms nearer to the surface, and this 

 elevation, which has been accurately surveyed by Sir Wyville 



* For a more detailed account see A. M. Norman, " The 'British Area' in 

 Marine Zoology," 'Ann. Mag-. Nat. Hist.,' ser. 6, vol. v, 1890, p. 345. 



