348 Rev. Canon Norman on the 



Ireland peculiar features present themselves. At some 330 

 miles west of the mouth of the Shannon the depth has in- 

 creased only to 650 fathoms, but beyond and so close to this 

 sounding that the recording figures meet on the chart we find 

 1570 fathoms. In fact here and opposite the greater part of 

 Ireland the continent is supported at its base on huge precipi- 

 tous buttresses some 5400 feet high. Towards the north of 

 Ireland the great abyss below these precipices trends towards 

 land in narrow tongue-like form, so that a * Porcupine ' 

 dredging at lat. 50° 24' N., long. 15° 14' W., gives 1630 

 fathoms. 



Again proceeding northwards we find the area of submarine 

 Europe vastly enlarged and stretching further and further 

 westwards, and 13 degrees or, say, 780 miles are crossed before 

 we can meet with a 1500-fathom sounding. 



To the north of this again we can pass from the north of 

 Scotland by the " Wyville-Thomson Ridge " and " Faroe 

 Banks " to Faroe, and thence by the " Faroe Ridge " to 

 Iceland in less than 300 fathoms, and in another 100 fathoms 

 we find a passage from Iceland to Greenland, while the under 

 1500 fathoms area has enormous extension southward. This 

 vast submerged continental land separates the basin of the 

 Atlantic from that of the Arctic Ocean. 



The mention of the " Wyville-Thomson Ridge" brings us 

 to the explanation of the irregular northern demarcation of the 

 British area indicated on the map and given in definition. 

 The reason why this line of demarcation must be brought 

 nearer to the Shetland Isles than midway to Faroe is as fol- 

 lows : — Crossing diagonally lat. 60° N. and running from the 

 shallows of the British seas W. by N. there exists a narrow 

 ridge, which separates depths of 500-600 fathoms of the 

 Atlantic from similar depths of the Arctic Ocean, such great 

 depths of these oceans here alone thus closely approachiug each 

 other. On the southern side of this ridge the waters are affected 

 by the Gulf-stream, and at the bottom of this " warm area " at 

 the depths mentioned the temperature is about 48° Fahr. The 

 Gulf-stream coming against the ridge can only overflow it, and 

 while the surface to the north of this ridge is thus warmed, the 

 depths below in the " cold area " remain unaffected, and are at 

 the low temperature of from freezing-point, 32° Fahr., to 33° 

 Fahr. This " cold area," or most southern projection of the 

 Arctic Ocean on the northern side of the "Wyville-Thomson 

 Ridge," is known as the Faroe Channel, and has a somewhat 

 boot-like form, widening beneath the ridge. Here its depth is 

 500-600 fathoms, thence the depth regularly and gradually 

 increases northwards, until at the "Norway Deep" (about 



