ATOLL AND REEF FORMATION 231 



colonies have been standing for thirty years — an observation 

 of very great importance in this discussion. The present 

 condition of Keehng Island and of Pulu Liiar is prophetic of 

 the future of the whole atoll : the evidence it affords is in 

 direct opposition to any hypothesis of a deepening or widening 

 of the lagoon by a process of " solution." 



