CHAPTER XYI 



THE LAGOON 



In accounts of atolls it is often found that the lagoon is 

 regarded and described as though it were a pit — a sort of 

 lake that is situated on the summit of a submarine moun- 

 tain ; often it is supposed to be the water-filled crater of a 

 volcano. 



So long as such ideas concerning the nature of the lagoon 

 are held, no description of it is at all likely to depict its real 

 features, for no descriptions written under this belief will ever 

 make it apparent that the lagoon is really the top of a broad 

 reef, around whose edges a ring of islands is raised. In this 

 description it is assumed throughout that the lagoon is a 

 slightly submerged reef, whose surface has undergone some 

 modifications owing to its partial enclosure by the island ring. 

 The lagoon is a sheet of water with an area of some twenty-five 

 square miles, and over the whole extent of its area the after- 

 effects of its enclosure by the islands have not been equal. The 

 result is that to-day the lagoon may be divided, for the purposes 

 of description, into two parts : a southern shallow part ; and a 

 northern deeper part. It is of importance to note that the 

 shape of this southern part is exactly that already described 

 as belonging to the sandy lagoon shores of individual islands. 

 If all the southern islands, from Pulu Ampang on the east to 

 Pulu Panjang on the west, be imagined as one continuous reef, 

 then the shallow part of the lagoon is exactly what we would 

 expect its lagoon shore to be. It is also of importance to 

 notice that this crescentic shallowing of the southern portion 

 is gaining on the deeper northern part, exactly as the cres- 

 centic sand beaches of the individual islands gain on all parts 

 of the lagoon. The same process is evidently at work on a 



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