15:2 PROF. E. HULL, LL.D., F.R.S., F.G.S., OX THE SUE-OCEANIC 



Africau continent, and enters the Atlantic Ocean in lat. 6° S. 

 Its depth opposite Banana Creek only reaches to 9 fathoms 

 (54 feet), but at a distance of 5 miles to the westward under 

 the ocean, the soundings suddenly plunge down to depths ot 

 '22S and 242 fathoms (1,368 and 1,452 feet) representing the 

 head of the sub-oceanic river valley ; at this point its breadth 

 is about 2 miles, with well-defined, steep or precipitous sides. 

 At a distance of 50 miles from its head, the breadth of the 

 canon has increased to 10 miles, and its depth to 813 fathoms 

 (4,878 feet) from the surface, or 713 fathoms (4,278) from the 

 edge of the Continental Platform — here represented by the 

 lOiJ-fathom contour. From this point the descent of the 

 floor is gradual for the next 57 miles, when it reaches its 

 maximum depth of 1,200 fathoms (7.200 feet) below the 

 surface, and opens out on the general floor of the abyssal 

 ocean, bounded by banks of moderate depth and steepness. 

 The total length of the canon from its head below Banana 

 Creek to its enibonchwe is about 122 miles. Throughout 

 this distance, owing to the remarkably uniform slope of the 

 floor of the ocean from the 100-fatliom contour dowii wards, 

 there do not appear to have been any great falls or cascades 

 such as occur in the submerged channels of some of the 

 European streams. (See Plate.) 



In order to realise the length of this sub-oceanic valley we 

 have to compare it mentally with distajices Avith which we 

 are familiar, and I have taken a few of these at random ; 

 speaking in all cases approximately. For example, the sub- 

 oceanic valley is twice the distance from Kingstown to 

 Holyhead in crossing the Irish Channel ; it is more than twice 

 the distance from London to Brighton ; it is longer than the 

 distance from Loiidon to Bristol or Birnnngham, and it would 

 take a train three hours to traverse, travelling at the rate of 

 40 miles an hour — which is the average speed ot" "through" 

 trains for long distances. These comparisons may, perhaps, 

 enable the reader to realise the magnitude of this great 

 submerged river valley. Then we have to recognise that the 

 breadth of this gorge, near its centre, is seven miles, and it is 

 bounded in some parts by nearly vertical clifls more than 

 4,000 feet in height. As far as 1 am aware there is no 

 physical feature in Europe to compare with it. 



One would like to further dwell on the characteristics of 

 this magnificent submerged valley ; but I am restrained by 

 the consideration that 1 might be charged with unduly 

 giving way to fancy for my facts. 



