DEPOSITS AND ELEVATION. 33 



question the result of some domestic arrangement con- 

 nected with that hutj the shingle having been brought 

 up for some purpose from the beach, and perhaps aug- 

 mented by the refuse of mnssel-baskets. The Mytilus 

 and Patella seem to have been crushed by being trodden 

 on. The larger pebbles may have been brought for 

 pavement, the white ones selected for ornament, as is 

 still the custom in Wales and elsewhere. 



I am extremely unwilling to pronounce against the 

 genuineness of a bed which Mr. Binney has described 

 as raised beach, and do so with the greatest hesitation ; 

 but, to say nothing of negative probabilities, the shell- 

 remains do not look like fossils, nor does the bed look 

 like a beach-bank. If raised beach could be preserved in 

 this spot, it might be expected that something of the kind 

 would occur at lower levels of still less antiquity; but 

 no sign of it has occurred to me. 



I may mention that in order to test the mussel-refuse 

 conjecture I made the following experiment. I got a 

 sackful of mussels from a bed in Conway Bay, just as 

 they are now picked for food, and carefully washed off 

 the fragments of shells and small stones which were 

 amongst them, attached to the byssus and otherwise en- 

 tangled in the mass. These were sorted and put side 

 by side with the result of a similar classification of the 

 constituents of the bed. 



The mineral portions, small shingle and coarse sand, 

 were scarcely distinguishable, except that the stones from 

 the sack were more or less coated with a film of vegetable 

 matter. Of the twenty-three species of the bed, eleven 

 occurred amongst this batch of mussels, presenting very 

 similar conditions of fracture and wear. I presume that 

 the decay of the vegetable film would account for the 

 dirty feel of the shingle which I have referred to above. 



SER. III. VOL. IV. D 



