The North Carolina Field 235 



ing the young bodies that have not yet stored reserve 

 food in their tissues (see Chapter IV). The mere peri- 

 odical sprinkling of young oysters with silt is probably 

 not so destructive as it is generally supposed to be. 



It may be noted that other waters than these, that 

 successfully support oyster life, are also muddy. Silt is 

 constantly deposited over a great part of the European 

 oyster territory. The waters of the Chesapeake are 

 muddy. The finest of sediment is at frequent intervals 

 settling to the bottom about the Mississippi delta, where 

 flourishing oyster beds below low water are everywhere 

 present. In the light of these facts it may seem strange 

 that only here oysters should be generally absent from 

 the bottom. 



It will be shown presently that in these rivers oysters 

 do establish themselves below the low water level, along 

 the sides of reefs. They are confined to those localities, 

 and the bottoms elsewhere are barren. Such segrega- 

 tions are formed on shells that drop from the reefs above 

 and pave the bottom, no matter how soft it may be. Not 

 only is this true, but the young attach to these shells and 

 grow. This proves that, while the water is often ex- 

 cessively muddy, not enough silt is deposited to prevent 

 oyster growth when the bottom is once paved. 



The bottoms below tide lines are very generally barren, 

 then, only because, away from the immediate vicinity of 

 oyster reefs, there is no natural deposit of any foreign 

 objects to harden it. Experiments show that if a suffi- 

 cient number of oyster shells or other hard bodies are 

 spread on the softest of these bottoms during the breed- 

 ing season, so as to afford surfaces for attachment, beds 

 of oysters form on them, and spread at the margins, one 

 generation growing on the shells of another. On these 



