DEVELOPMENT OF THE ATOLE 261 



a long series of years ; but I do not imagine this to be at 

 all the fashion of development of the atoll. Every detail of 

 its structure points to the fact that the. increments to its 

 building have been added at quite irregular intervals : it seems 

 as though the land had taken a rapid stride, and then had 

 ceased from growing ; the quiescent period being again followed 

 by great additions to its substance. I think it may be taken 

 as a law of atoll growth that the processes of formation take 

 place by fits and starts. The evidences that we see of sudden 

 building increments are without doubt the evidences of storms 

 of exceptional violence ; and it is no doubt the unusual events 

 of wind and wave that initiate every process of atoll formation; 

 and that give fresh stimulus to the progress of their completion. 



We have therefore arrived at the stage in which bare 

 debris islets are raised about the edge of the reef, and in their 

 formation nothing, save the normal growth of coral, the 

 deposition of calcium carbonate, and the natural effects of the 

 winds and waves, is involved. 



That the final formation of the atoll is entirely dependent 

 upon the prevalent winds and seas seems to me to be quite 

 clear, and for its proof the examination of the charts of atolls, 

 and atoll groups, is all that is needed. Professor W. J. Sollas 

 has said (Brit. Ass. 1893) that clear evidence of the truth of 

 the theory of Subsidence is seen in the fact that atolls tend to 

 be elongated in the direction in which the group to which they 

 belong is stretched. Now far from taking this as evidence 

 that a .line of subsidence had taken place, I would regard it as 

 showing that the wind and waves that made the whole group 

 shaped each individual atoll of the group. 



The shape of the group, the shape of the atoll, and the shape of 

 the individual islands is impressed hy the agency of the normal 

 winds and waves ; and the stimulus of origin, and the increments 

 of building, are the outcome of the exaggerated violence of the normal 

 ivinds and waves. 



