The North Carolina Field 241 



cover that now and then certain of them break from the 

 reef and roll down the steep sides into the channel. This 

 occurs when storm waves at high tide dash against the 

 clusters, breaking or uprooting them. In winter, the 

 grinding action of ice adds to the number of oysters lying 

 on the deeper bottom below the tide lines. The ac- 

 cumulation is made slowly, but continues from year to 

 year, and finally a firm shell bottom, sometimes many 

 yards in width, is formed parallel to the sides of the 

 reef. On this are found not only clusters that have 

 rolled down, but single oysters scattered here and there, 

 which, having grown without crowding, have become 

 large and rounded. In the breeding season, swimming 

 young attach to these deeper shells as well as to those be- 

 tween tide lines, and in this way the deeper bed grows 

 rapidly. As one would expect, these, if left to grow 

 undisturbed, become as completely clustered and worth- 

 less as the reef oysters above them. But wind, waves, 

 and frost, thus operating to form a new bed, have scat- 

 tered over it so many single oysters that they begin to be 

 sought by tongers, and in this way is introduced the 

 more important agency that makes the tonging ground 

 more extensive and valuable. 



Consciously or unconsciously the tongers begin to 

 practise a very successful method of oyster culture. They 

 lift from the bottom numbers of empty shells, small 

 clusters, and a few single oysters of large size. Because 

 the clusters are comparatively small, they contain some 

 individuals of good shape and size. These are separated 

 from the others on a culling board carried by the boat, 

 and the empty shells and small oysters from the broken 

 clusters are returned to the bottom. Two important re- 

 sults follow this practice. The area of the shelled bot- 



