102 W. R. Hudleston — E. Margin of ISf. Atlantic Basin. 



enormous volume of water, and unless there was a corresponding 

 sinking-in somewhere, some perceptible effect must have been 

 produced on the sea-level. I might mention here that in Mobn's 

 admirable work a number of serial soundings are given tbroughout 

 the Norwegian Atlantic. These of necessity are drawn with tbe 

 vertical scale much exaggerated. In this way even the central 

 deeps may be made to look like canons with V-shaped valleys 

 at the bottom. This is especially the case in the deep-sea between 

 Spitzbergen and Greenland, and it is easy to make a slope of 

 3° or 4° look almost vertical. In the southern part of the 

 Norwegian Atlantic the average rise of the sea bed from its greatest 

 depths towards the coast of Iceland, the Fseroes, and Norway is 

 stated to be 1 in 188, or about one-third of a degree. 



Before proceeding any further south with our bathymetrical survey, 

 we ought to consider the geological bearing of the details already 

 given, as far as practicable. It is obvious from an inspection of the 

 accompanying map that the eastern part of the North Atlantic, the 

 Norwegian Atlantic,^ and a portion of the North Polar ocean all 

 belong to one and the same great geosynclinal depi'ession, which 

 has been partly interrupted by volcanic extravasation, more especially 

 in the region between Shetland and south-east Greenland. This 

 linear arrangement of what I may call, in general terms, the North 

 Atlantic oceanic depression, extending from the North Pole in the 

 direction of the Equator, seems to call for some explanation on 

 physical grounds. We are reminded of the two principal schools of 

 geographical evolution, and of the theories relating to the permanence 

 or non-permanence of the major features of the earth's crust. Ever 

 since the leading facts of oceanography were made known there has 

 been a tendency in some quarters to regard the great oceans as 

 permanent featui'es. If this is really the case, then the suboceanic 

 continental slopes would, under certain limits, come to be regarded 

 as permanent also. 



Dana and Wallace have argued strongly in favour of the 

 permanence of the great features of the distribution of land and 

 water on the earth's surface, but the majorit}-^ of geologists in 

 England have rather clung to the Lyellian doctrine as to a complete 

 change of land and sea having taken place at various periods of 

 geological time. The secular interchangeability of the great land 

 and water areas has also received much support from the view that 

 the Chalk is of necessity a deep-water formation — abyssal according 

 to some. Wallace,^ it is well known, considered that the doctrine of 

 the permanence of continents and oceans lay at the root of all our 

 inquiries into the past changes of the earth and its inhabitants. He 

 thought that this doctrine received strong confirmation from the 

 evidence adduced by Darwin, who observed that hardly one truly 

 oceanic island had been known to afford a trace of any Palaeozoic or 

 Mesozoic formation ; so that islands of this class have not preserved 



1 In Bartholomew's map (Fig. 1) the northeru part of the Norwegian Atlantic is 

 called the ' Greenland Sea.' 

 * "Island Life." 



