56 Bev. 0. Fisher — The Platform of Western Europe. 



II. — Pkofessor Hull " On the Submerged Platform of Western 



Europe." 



By the Eev. Osmond Fisher, M.A., F.G.S. 



Ty\0 appreciate more fully Professor Hull's interesting paper " On 

 JL the Submerged Terraces and Kiver Yalleys bordering the 

 British Isles," it is necessary to refer to the Transactions of the 

 Victoi'ia Institute,^ in which the paper is illustrated by a map 

 showing the contour-lines and soundings. The author thinks that 

 the steep descent from the surface of the 100-fathom plateau to the 

 abyssal floor of the Atlantic is analogous to an escarpment, instancing 

 the Cotteswold Hills and other examples, and argues from this that 

 the steep descent in question has been due to the forces of subaerial 

 denudation, and has had a terrestrial origin. But in his " general 

 conclusion " he mentions marine as well as atmospheric erosion. 

 This seems to show that he does not exclude the supposition of the 

 descent being possibly an ancient sea cliff, to which one would think 

 it more analogous than to an escarpment, for, as Mr. Jukes-Browne 

 observes, the latter term implies the termination of a series of beds 

 of one geological age, which it cannot be supposed occurs here. 



I notice that in this discussion there has been no reference made to 

 a masterly paper by the late Mr. R. A. C. God win- Austen — " On the 

 Valleys of the English Channel." ^ He tells us that he " had 

 frequent opportunities of cruising about this Channel, and had been 

 enabled at one time or another to visit nearly every portion of its 

 shores on either side, and to examine its bed with the dredge and 

 souuding-lead." The map which illustrates his paper consequently 

 gives several interesting points of detail, which do not appear in the 

 Admiralty chart of the English Channel. He says that " along 

 the opening of the Channel there is an obvious configui'ation of hill 

 and valley, and an amount of inequality equal to that of the most 

 mountainous parts of Wales." Regarding the junction of the 

 channel with the Atlantic we read — " Beyond the 200-fathom line 

 the outline is irregular, and sinks rapidly to very great depths. 

 This remarkable fact occurs not only at one particular spot, but is 

 continued northwards, and in the contrary direction has been traced 

 by Captain Vanhello from Cape Finisterre to the parallel of the 

 Lizard." He states that the ridge of the Little Sole Bank is 

 placed on the east edge of the 200-fathom line. " Of the true 

 nature of such a sudden line of depi'ession we can at present only 

 form conjectures. It may represent lines of old escarpments, or, 

 should lines of sea cliffs have gone down rapidly into deep water 

 where no mechanical action could modify them, such features would 

 be preserved. Lines of faults and upheaval would also prevent such 

 unequal soundings ; but the outline is too irregular to represent the 

 termination of the sedimentary mass of the present seas ; besides 

 ■which we have constant indications of a surface of bare rock." 



1 Vol. XXX (1898). 



2 Quart. Journ. Geol. Soc, vol. vi (1849), p. 69. 



