286 Scientific Proceedings , Royal Dublin Society. 



evidencmg alternate periods of repose and disturbance, I have fully 

 discussed elsewhere. — [Trans. Dev. Assoc, vol. xv., pp. 359-365.) 



While the above facts testify to the existence of occasional 

 motion on the bed of the English Channel, the following facts 

 negative the possibility of such motion being due to any violent 

 currents of translation that affect the surface of the bottom : — 



(1). The occurrence of angular shingle at various points westward 

 of SciUy.— (Map of English Channel, E. A. C. Austen, U. J. G. S., 

 vol. vi.) 



(2). The perfectly unworn state of chalk flints trawled fifteen or 

 twenty miles off the Start and Eddystone. It may be observed, 

 that two specimens, weighing respectively 3 lbs. 2 oz. and 2 lbs. 

 14 oz., taken twenty miles south-west of the Start, were unrolled. 

 A small flint, 8 oz. in weight, taken fifteen miles south-west of the 

 Eddystone, was very slightly abraded, though one weighing 6 lbs., 

 taken five miles further to the south-west, was perfectly unrolled. — 

 [Trans. Dev. As'soc, vol. xii., p. 293, and " Corrigenda," vol. xv., 

 p. 365.) 



(3). The occupation of the Channel-bed by an extensive fauna, 

 which could not exist in the face of currents sufficiently strong to 

 sweep along sand and shingle. 



The advocates of powerful waves of translation, whether tidal or 

 •otherwise, have never disposed of the objection that the Shambles 

 Shoal off Portland, composed as it is of light comminuted shells, 

 could not possibly exist in the face of any such waves of translation. 

 Waves that could sweep shingle up Channel to Portland would 

 naturally sweep away every vestige of a shoal composed of such 

 light material, at any rate for a time. But it is well known that 

 the shoal in question is to all intents and purposes permanent. Sir 

 John Coode has described it as " an immense bank of fine broken 

 shells, lying south-east of Portland, which was now in the same 

 condition as when surveyed by Mackenzie, about one hundred years 

 since, and having now, as then, a depth of only 11 feet of water 

 over the crest" (P. 60). 



The persistence of the Shambles has been a perplexity to scien- 

 tists from Sir H. de la Beche's time up to the present, and, so far as 

 I am aware, the advocates of the wave of translation theory have 

 never attempted to account for the phenomenon. 



The persistence of shoals and sandbanks in the face of waves, 

 however heavy, presents no difficulty so long as the waves are 



