DEPOSITS AND ELEVATION. 29 



a few Purpura lapillus, and at least one heap of Buccinum 

 undatum. At the lower edge the heaps yet remain massed. 

 Above they are more distributed on the slope. 



Bones and teeth of ox, sheep, and roebuck, and bones 

 of some birds occur. I have found at various times 

 burned bones, and once a piece of red earthenware, but 

 hitherto no utensils of any kind. Most of the bones and 

 shells have a very recent appearance. 



xvi. Lastly, Mr. Bonney (Geol. Mag. iv. 292) men- 

 tions as occurring at intervals in the sand cliffs on the 

 western or Conway-Bay shore seams of Mytilus edulis, 

 which he has assumed to indicate '^ a period of depression 

 during which the mussel-beds were formed ^^ and of sub- 

 sequent upheaval. 



I am afraid those mussel-beds must be set down as 

 appertaining to the most recent human period. A corre- 

 spondent of ' Loudon^s Magazine of Natural History ^ for 

 1830 describes the taking of large quantities of mussels 

 and their being boiled to get the fish out, and the 

 searching of the latter for pearls. He then says, " the 

 huts which have been erected for convenience of boiling 

 the fish are on the extremity of the marsh about a mile 

 from Conway," on the west of the estuary. There are 

 still to be seen at that spot great beds of mussel -shells, 

 which are so abundantly distributed in the sections and 

 on the surfaces of the sand dunes as to give them a blue 

 colour distinctly visible in suitable light to a great 

 distance. Mr. Glover tells me that he has often watched 

 the process in the eastern bank of the river, i, e, making 

 Mr. Bonney's beds. 



The shells are not aggregated as if dead in locOj but 

 consist of separate valves confusedly massed in patches 

 too limited in extent, and often too thick vertically, to 

 bear any comparison with the mussel-beds of the Bay. 



There is a spot near Tywyn, between the railway and 



