Bordering the British Ides. 357 



the ocean. It will be observed that as compai'ed with the British 

 subcoastal featui'es there is a general resemblance, but with one 

 important exception, namely, the absence of the representative of 

 the " Blake Plateau." We may, without hesitation, recognize our 

 British platform as the equivalent, of the Continental Shelf: but, as 

 I have already shown, the former terminates along the margin of one 

 great escarpment descending to depths of nearly 10,000 feet. A solid 

 escarpment of this kind indicates a slow continuous elevation, after 

 the British platform had been planed down by wave action and 

 subsequent depression after a lapse of time. On the coast of the 

 American continent, however, there appears to have been an 

 intermediate period ref)resenting a pause in the process of elevation 

 and subsequent depression, during which the second shelf, or " Blake 

 Plateau," was elaborated. 



VII. Geological Age of the Submerged Features. — The formation of 

 the British platform, like that of the American "Continental Slielf," 

 may be referred back with confidence to the Mio-Pliocene period, and 

 that of the grand escarpment to the succeeding early Pleistocene or 

 Glacial stage. This view is in harmony with analogy and with what 

 we know of the physical conditions of these periods. The Mio- 

 Pliocene stage was one of great terrestrial changes of land and 

 sea over the European and adjoining areas ; but the climatic 

 conditions were warm and genial, with a foretaste of more rigorous 

 conditions towards the close. An elevation of 100 to 200 fathoms 

 round our coasts would have been insufficient to have brought 

 on glacial conditions, although undoubtedly tending in that direction 

 in our more mountainous districts. But a further elevation to the 

 extent of several thousand feet would undoubtedly bring about such 

 conditions; and we are, therefore, justified in inferring a close 

 relationship between this latter rise of the land with the adjoining 

 oceanic bed and the incoming of those Arctic conditions which 

 resulted in covering, not only our mountain heights but also the 

 adjoining plains, with perennial snow and glaciers. 



Having already in my former paper treated the subject of the 

 origin of the Glacial period at some length, it is unnecessary that 

 I should dwell upon it here, or explain how the great rise of the 

 land would necessarily result in bringing about glacial conditions in 

 the North Temperate zone, especially when combined with alterations 

 in the temperature of the Gulf Stream. On these points the reader 

 is referred to my former communication, and I shall only add here, 

 that the conclusions which I ventured to enunciate on the basis of 

 the statements of previous authors have been fully verified by my 

 own study of the Admiralty charts, which I have here communicated 

 to the Institute.^ 



1 Professor T. McK. Hughes, in his interesting paper on "The Evidence of 

 Later Movements of Elevation and Depression in the British Isles," read before the 

 Institute in 1879, postulates a rise of the laud to the extent of several thousand feet 

 and infers the climatic changes wliich would thence result. I hope he will now 

 concur with me that such a rise has actually taken place. — E. H. 



