ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. 113 



the bottom deposit increases with distance outwards, or conversely, the 

 percentage of the finer deposit increases as the coast-line is approached, 

 till at some eight to ten miles outside tlie Eddystone there is found, in 

 40 fathoms, a deep accumulation of fine sand, 92 to 95 per cent of which 

 is less than 1 mm. in grade.* 



It would be difficult to account for these facts except on the 

 assumption that there is a constant tendency for the finer material to 

 be drifted, by combined tidal and wave action, from the outer waters 

 of the Channel towards the coast-line, the direction of the drift being 

 apparently, so far as the English side of the Channel is concerned, 

 north-easterly. On such an assumption, with the continuous trans- 

 portation of the finer material from the more distant positions, the 

 greater degree of exposure of the stones in like proportion would be 

 accounted for. Without the presence of a constant process of the 

 kind no explanation would seem adequate to account for the fact that 

 in the midst of shifting deposits brought from other regions and 

 continuously augmented by the local growth and decay of numerous 

 lime-secreting organisms, even small pebbles of no more than a centi- 

 metre or two in height are found again and again, affording an un- 

 disturbed base for delicate animal growth, evidently for a long period. 



Whether the present conditions are undergoing any change, or 

 whether they represent a state of equilibrium maintained between the 

 factors of deposition and tidal action it would be of deep interest to 

 know. In either case there is very little doubt that at the present 

 time, over almost the whole of this area, the true stony bed of the 

 Channel is but barely obscured by a very thin, superficial covering. 



* It must, however, be expressly stated that it is not intended here to assign to this 

 last formation, represented by the samples (2) and (69), an origin in the outer waters 

 of the Channel. The inference is rather that somewhere between it and the region of 

 sample (71) the outer Channel drift encounters an opposing action of coastal currents, 

 to which latter it would seem that this distinct deposit is properly to be ascribed, thus 

 preventing its further distribution seawards and deflecting. the outer Channel drift itself 

 from the actual coast-line. — L. R. C. 



