Corresjjondence — Professor E. Hull. 233 



platform terminates, ' an escarpment ' or ' declivity ' of 7,000 feet or 

 more, but that is a very different thing from a ' vertical precipice ' 

 of that height. The nearest approach to the above quotation I can 

 find in what I have written is in my paper published in the 

 Transactions of the Victorian Institute for 1896-7, and subsequently 

 in the Geological Magazine, August, 1898, in which I state, and 

 state truly, if the soundings are correct, that the escarpment off 

 the Porcupine Bank of 7,800 feet "is quite precipitous" (p. 354) ; 

 also that there is "a sheer precipice of 5,000 feet just south of La 

 Eochelle Bank"; but in neither case do I use the word 'vertical,' 

 although, in some parts of their descent, the cliffs no doubt are 

 vertical. I draw a distinction between a 'precipice' and a 'vertical 

 precipice.' It is very rarely that precipices of a thousand feet and 

 upwards are vertical ; but they do not cease to be precipitous at any 

 angle less than (say) about 45° to 50° from the vertical. That some 

 faces of the outer declivity approach these angles, or even exceed 

 them, throughout a portion of their descent from the edge of the 

 British-Continental platform, is fully borne out by the soundings, 

 but it will be observed that this is a very different statement from 

 that which has drawn forth the emphatic reply of the gallant 

 Admiral. 



But that there ai'e precipices, in the sense I have explained above, 

 of 6,000 or 7,000 feet in some of the submerged river valleys, such 

 as those (presumably) of the Mondego (lat. 40° 30' N.) and that 

 which lies off Cave Carveiro (lat. 39° 30' N.), is clearly shown by 

 the soundings. I cannot expect Admiral Wharton to have recog- 

 nized them ; for even in tracing by a light dotted line the 100-fathom 

 contour on the Admiralty Charts the di-aughtsraan has sometimes 

 lightly skipped across these indentations, which he probably con- 

 sidered of no consequence ; still, there they are, when the isobaths 

 are accurately worked out. I cannot, however, but feel obliged to 

 Admiral Wharton for his quotation from the report of Captain 

 Hoskyn when he says, regarding the form of the great declivity : 

 " The intermediate soundings give no evidence [off the coast of 

 Iceland] of a precipice, but a mountain of this height on the land 

 would present an imposing appearance, with perhaps some steep 

 escarpments." This is exactly my own view ; and if the reader 

 will examine the sub-oceanic sections given with the map in my 

 original paper in the Transactions of the Victoria Institute, quoted 

 above, he will see that this is so. 



Referring now to Mr. Hudleston's important contribution in the 

 March and April numbers of the Geological Magazine, I have 

 nothing to complain of the manner in which he has dealt with my 

 own views ; and I am glad that, once and for all, he has given his 

 powei'ful aid in favour of the view that the British-Continental 

 shelf was at a former time a land surface, and that " so long 

 as Professor Hull confines himself to tracing the old river-courses 

 cut in the continental shelf he is pretty safe" (p. 153). It 

 then only remains to be determined to what depth below the 

 geueral level of the platform the channels may be carried down ; 



