1012 OYSTERS, AND ALL ABOUT THEM. 



1. Over-dredging has not been the cause of the 

 decreased production of oysters. The decrease has not 

 arisen from any cause over which man has control, but 

 from a general failure of spat occasioned by the inclement 

 seasons of the past twenty years. 



2. The beds at Poole, Cancale, Granville, &c., are 

 special cases acted on by local circumstances only, and do 

 not prove the rule. 



3. Oyster grounds cannot be dredged out. One bushel 

 only left on a ground during a good spatting year would 

 be sufficient for an enormously increased supply. 



4. That it does oyster grounds good at all times to be 

 cleansed from weeds, mud, and vermin. 



5. That in the estuary of the Thames five-fingers are 

 always kept and sold for manure. That dredging disturbs 

 and disperses the enemies. In fact the injury inflicted by 

 allowing the enemies to prey unrestrainedly on the oysters 

 is greater than that which any amount of dredging can 

 accomplish. 



6. From the fact of the layers of oyster-shells being 

 superimposed one on the other, it may be assumed that 

 each bed only lived a short time comparatively. The 

 deposit of sand and clay, &c., which is frequently seen 

 between the layers, points to the cause of death, and 

 judicious working might have removed this. Further, 

 each bed must have been defunct before the next could 

 have been deposited. 



7. Man's influence is so slight when compared to the 

 immense operations of nature either for beneficial or des- 

 tructive purposes, that it may be practically left out of 

 account when considering the question of the supply of 

 fish and molluscs. 



