296 PROF. J. PRESTWICH ON THE RAISED 



side of the Channel I have shown that the Brighton Beach extends 

 to Eastbourne, and there is reason to beheve that it was not far in 

 advance of the present coast-line at Folkestone and Dover, while 

 traces of a contemporaneous (but not marine) deposit at the same 

 level exist near the Isle of Thanet. The only indication of a sub- 

 merged land in the Channel is that afforded by the Yarne and Ridge 

 shoals, which at low water are covered to the depth of only 2 

 fathoms, but these banks consist of Portland and Purbeck strata, 

 and no Palaeozoic rocks were found there by M. de Gamond, 

 nor do any exist on the French coast opposite. These shoals 

 may represent a small island with deep water on either side, but 

 not a barrier across the Channel. That the Straits were open, and a 

 drift from the northward then existed, is on the other hand indicated, 

 not only by the presence of granite-pebbles in the Sangatte Raised 

 Beach, but also by a circumstance mentioned by Capt. T. B. Martin, 

 formerly Harbour-Master at Ramsgate, who says that the fishermen 

 employed there in trawling are " occasionally impeded by masses 

 of granite, serpentine, sandstone, slate, and various other stones, 

 which are scattered indiscriminately over the bed of the ocean." ^ 

 The granite, Palaeozoic, and other pebbles which were found by 

 Godwin-Austen in the Channel between the Calvados and Sussex 

 coasts may, as well as these off Ramsgate, therefore be due to an 

 ice-bearing current from the North Sea, and this is confirmed by 

 various other facts. 



The ice-floes and bergs, with their detrital loads, would as a rule 

 keep in deep water at a distance from the shore, unless other con- 

 ditions, as those on the coast of West Sussex, favoured their nearer 

 approach. The great bay which there extended at the time of the 

 Raised Beach from Waterbeach, near Chichester, to Bembridge, with 

 a width of about 15 miles and a depth, from Pagham to Portsea, of 

 10 miles, presented such conditions ; for, taking the level of the old 

 beach near Chichester at about 100 feet, and at Bembridge at 30 

 feet, the water over the Pagham and adjoining flats must have been 

 from 50 to 80 feet deep. In this gulf ice-floes from the eastward 

 would become embayed and stranded, and there no doubt they 

 dropped the blocks of granite and other rocks now found scattered 

 over all that area. 



One circumstance which for a time seemed to offer an insurmount- 

 able objection to a drift from this direction was the presence, with 

 the foreign-rock boulders at Hay ling Island and Bracklesham, of 

 pieces of silicified wood identical with the fossil wood of Portland. 

 For this wood, which is of a marked character, is peculiar to that part 

 of our coast ; and it might have been concluded that the drift had 

 been from Portland westward, and not from the eastward and north- 

 ward, had not another explanation suggested itself. I had seen 

 similar wood in the Boulonnais, though not on the coast ; but in 

 Dr. Fitton's description of that district I find the following remark : — 

 " The line of the cliffs from Equihen on the south of Boulogne to 

 Cape Grisnez on the north of that place is capped at intervals with a 

 ^ Trans. Geol. Soc. 2nd ser. vol. vi. (1841) p. 161. 



