< 



\r- 



5l 



P^r. 



X 



''tiiii 



i3. 





4; 



H 





^ 



^ 



r 



fUekkti 



- fo 



be 'M 



% 



river l^ F 

 /the iD^^^ 



a 



dbear^ 



saffij 



arns 



its f^'f^'^' 



•"b n^ay ^\ 

 Dgtb ^^'^, at 







^.1 '^^ 



f 



Cii. XLVIII.] 



IN SUBAQUEOUS STEATA. 



5/5 



After the storm of February 4^ 1831^ wlieii several vessels 

 were wrecked in the estuary of the Forth^ the current was 

 directed against a bed of oysters with such force, that great 



own 



manj 



manied above nign-water marK. i coiiectea 

 oysters, as also the common eatable whelks {Buccinum) , 

 thrown up with them, and observed that, although still living, 

 their shells were worn by the long attrition of sand Avhich 



as they lay in their native bed, and 



them 



om the mere 



tempest by which they were cast ashore. 



From these facts we learn that the union of the two parts 

 of a bivalve shell does not prove that it has not been trans- 

 ported to a distance ; and when we find shells worn, and with 

 all their prominent parts rubbed off, they may still have been 

 imbedded where they grew. 



Burroiving shells. — It sometimes appears extraordinary, 

 when we observe the violence of the breakers on our coast, 

 and see the strength of the current in removing cliffs, and 



man J 



and frap'ile 



shells should inhabit the sea in the immediate vicinity 

 of this turmoil. But a great number of the bivalve Tes- 

 tacea, and many also of the turbinated univalves, burrow in 



sand 



mud 



The Solen and the Cardium, for example, 

 which are usually found in shallow water near the shore, 

 pierce through a soft bottom without injury to their shells ; 

 and the Pholas can drill a cavity through mud of considerable 

 hardness. The species of these and many other tribes can 

 sink, when alarmed, with considerable rapidity, often to the 

 depth of several feet, and can also penetrate upwards ao-ain 



atter be heaped upon them, 

 expend its fury in vain, and 



mass 



may 



may 



them 



may 



fossil 



stated that, at the depth of 950 fathoms, beti 

 and Ceuta, Captain Smith found a gravelly 

 fragments of broken shells, carried thither probably from the 



bottom 



/ 



