THE ISLAND BEACHES 169 



in which the roots of former generations of coco pahiis may be 

 found, merge gradually into the island debris, there being no 

 heaping up of boulders to resist the sea's encroachment ; and 

 here, with hisjh tides and a stronsf wind, the sea will rush over 

 the island in an alarming manner. 



Although the seaward beach is usually made up of chips 

 and fragments of coral, still, in some places, both the lagoon 

 beach, and the sea beach may be composed of fine coral sand. 

 Where the island is a pure sand formation it is generally 

 sheltered on its seaward side by the accumulation of large 

 boulders. Within the shelter formed by pieces of detached 

 barrier, and on a firmly cemented rock basis, is piled fine sand 

 and small debris which gradually slopes from the seaward edge 

 upwards to the lagoon shore. Such a structure is the beach 

 of Pulu Bras and of Pulu Pasir. No large pieces of coral 

 enter into the formation, and on either side of that portion of 

 barrier on which they have their basis, sand spits run out 

 towards the lagoon. The seaward beaches are seen in their 

 most perfect form to the windward of the atoll, and at the 

 southern point of Pulu Atas, and at the south-east aspect of 

 Keeling atollon, the beaches rise steeply piled to a height of 

 twenty feet or more. No better idea of the wonderful force of 

 the Trade -driven waves can be gathered than by studying these 

 piles of massive boulders tossed up by storms. In these 

 windward beaches there is very little sand, save that piled by 

 the wind beyond the reach of the ordinary seas. 



Of whatever formation the beach may be, it is its chief 

 characteristic that, in its minor details, it is perpetually 

 changing with the cycle of months and years ; and a daily 

 walk round an island, during a year's progress, will note per- 

 petual alteration in the disposition of sand and rock, in the 

 distribution of silt bank and channel ; each changing always 

 as the currents around the atoll wax and wane locally. To-day 

 a boulder-piled rise will merge to the sea by a sandy beach 

 and form a temporary spit, on which the cast ectoskeletons of 

 Crustacea, the dead echinoderms, shells of all sorts, and algse, 

 will come ashore in profusion ; and in a few weeks' time it will 



