RIVER VALLEYS OP THE WEST AFRICAN CONTINENT, ETC. 151 



to show beyond question that these great terrestrial oscilla- 

 tions of level which have characterised die coast of the 

 British Isles and of Western Europe are continuous, and 

 undiminished in extent, far beyond the equator itself- — and that 

 the lands bordering the eastei'i) Atlantic, through its Avhole 

 extent, ha-ve been subject to the same vertical movements 

 which, as we have seen, characterise those of the region to 

 the north of the Straits of Gibraltar, 



Reference to Previous Authors. — In 1887, Mr. Edward 

 Stallibrass, F.R.G.S., read a paper before the Society of 

 Telegraphic Engineers on " Deep Sea Soundings in connec- 

 tion with Submarine Telegraphy," * in which he describes the 

 sub-oceanic channel of the Congo, and traces it from its 

 upper limit, where the river itself enters the Atlantic, down 

 to the 1,000-fathom contour, givhig the length of the channel 

 at 100 miles. The map which accompanies his paper show- 

 ing the course of the submerged Congo agrees very closely 

 with my own, but is on a smaller scale than that of the 

 Admiralty Chart, and fails to give the full length of the 

 submerged channel, which actually extends some 20 miles 

 farther out to sea than is shown by this author. 



In the remarkable paper contributed by ]\lr. Warren 

 TJpham, of the United States Geological Survey, on the 

 "Causes of the Ice Age," in which he indicates his opinion, 

 founded largely on the existence of the submerged valley of 

 the Congo, that the great " epeirogenic movements" which 

 characterised the close of the Tertiary period embraced the 

 western side both of Europe and Africa, he states that, from 

 soundings carried out by Mr. J. Y. Buchanan for telegraphic 

 purposes, he found the channel of the Congo to extend 80 

 miles under the ocean, and to a depth of more than 6,000 

 feet, and he proceeds to give further details regarding the 

 breadth and depth of the channel.t Here, then, we have two 

 independent authorities lor the existence of this great sub- 

 oceanic river valley. Both, however, fail to give the entire 

 length of the valley, and, therefore, to give an adequate idea 

 of the extent and depth of this magnificent submerged canon ; 

 it will, therefore, not be considered a wholly gratuitous 

 undertaking if I attempt a description of it drawn from my 

 own examination of the soundings on the Admiralty Charts. 

 The Congo. — The Congo is one of the largest rivers of the 



* Journ. Soc. Teleg. Engineers, vol. xvi, p. 479. 



t Warren Uphain, Journ. Vict. Inst., vol. xxix, p. 218. Mr. Upliam 

 quotes the Scot. Ueog. Journ. vol. iii, p. 217 (1887). 



