The North Carolina Field 237 



The explanation for such a relation between so many 

 individuals is simple. A single large oyster shell may 

 lie on the surface of the mud near living oysters. If it 

 is free from slime when oyster embryos are swimming 

 in the water, it affords a surface for the attachment of 

 one or more of them. Usually several establish them- 

 selves on it. Not all of these live, and many perish 

 early. A few continue to live and extend their bodies 

 upward into the current. Only those that grow upward 

 can survive, for the currents steadily deposit silt obtained 

 from the land. Slowly the original shell is buried, and 

 finally disappears, and the mud creeps up to the younger 

 individuals that it bears. If their bodies are growing 

 outward from its sides, they, too, are covered. Again 

 in the breeding season, a second generation attaches it- 

 self to the exposed portions of the shells of the first. If 

 sediment has collected rapidly, they become fixed only 

 to the exposed edges of the shells; if slowly, to any part 

 of them, in this case forming a larger and broader 

 cluster. 



Year after year the process continues. The earlier 

 generations are buried and die, but still their empty shells 

 lift up their descendants into the life-giving streams 

 above. The time finally comes when the earlier shells 

 are completely dissolved, if the mud contains acids 

 formed by the decay of organic matter, but it is often 

 possible to distinguish in the cluster uprooted from the 

 mud, six or seven generations of oysters. 



The oysters of these river banks are of little value 

 commercially, because of their form and condition. Most 

 of them are narrow and greatly elongated, and this is due 

 entirely to crowding. Like clams in small and irregular 

 spaces between stones, their growing bodies conform to 



