21G PROF. E. HULL, F.E.S., ON DR. NANSEN's BATRYMETRICAL 



Then, the Adour, which also, according to my investigations, 

 certainly comes down to a similar depth, about 6,000 feet. 

 Dr. Nansen in his work on the Polar ocean (vol. iv) when 

 describing the Adour river valley, says : " it is almost impossible 

 to give any other explanation of its existence than that of a 

 former river valley at a time when the whole region was elevated 

 into land." This, you will admit, is very valuable testimony. 



Then we proceed northwards and find that the channels of 

 several of the rivers entering the ocean from Spain and France 

 are also continued out into the ocean across the platform, and 

 descend almost to a similar depth as the base of the platform 

 itself. 



Similar is the case with the British Isles. In the case of one 

 of the old river valleys, we have an illustration of a submerged 

 valley in the English Channel ; and it is remarkably determined 

 and represented on the Admiralty Chart under the term of the 

 " Hurd Deep.' It is 60 miles in length, running up the channel 

 parallel to the coasts, along the centre between the coasts, and 

 it terminates towards the Straits of Dover, gradually dying out 

 where we may suppose the river had its origin ; it also dies out 

 towards the western margin of the continental platform, 

 doubtless owing to silting. The floor of the English Channel 

 itself, and of the Irish Channel, are only parts of the great 

 submerged plain of the continental platform ; but this is a river 

 valley cut out and left open to the present day, so that the 

 Admiralty surveyors have marked it as the Hurd Deep, after 

 the name of the naval officer who carried out the soundings 

 whereby the river valley was discovered. 



2. The Arctic Ocean. — Nansen's great discovery, partly from 

 actual soundings, partly by inference based thereon, is the 

 occurrence of a profound Arctic basin which, unless abruptly 

 terminated by the uprise of a mountain mass several thousand 

 feet in height from its floor under the pole, of which there is no 

 evidence, necessarily extends under the pole itself. (See Plate.) 

 This vievy is strongly supported by Professor Spencer in an able 

 paper which has opportunely reached my hands* in which the 

 whole question is discussed — and which is illustrated by an ex- 

 cellent little map of the Arctic regions. In this map, which is to 

 some extent based on that of Nansen, in his great work,f but also 

 on original researches, it is shown how the continental platform 



* No. 11 in the list of papers appended to this essay. 



t Bathymetrical Features of the North Polar Sea, (Jhristiauia, 1904. 



