8 Christmas Island. 



When a heavy sea strikes the cliffs, the air is driven through these 

 passages with great violence, and sometimes accompanied by a 

 column of spray GO or 70 feet high. These blowholes are most 

 numerous on the south coast, where the cliffs are exposed to the 

 heavy ocean swell caused by the south-east trade- wind, which 

 prevails during the greater part of the year. Along this coast the 

 cliffs are cut up into narrow, finger-like masses, and their .summit 

 for some distance inland is bare of vegetation, being continually 

 swept by the spray, liock-pools containing small living fish some- 

 times occur on the cliff top. On the north coast, which is more rarely 

 exposed to a heavy sea, the cliffs often form a continuous wall for 

 long distances. The structure of the sea cliff will be described in 

 more detail in the geological part of this memoir. Here it may 

 be mentioned that by far the greater part of it is a section of a 

 recently raised fringing reef; but in some places — e g., on the east 

 coast — the sea has cut back to the older and moi e central parts of 

 the island, and in such places the cliff" may consist largely of vol- 

 canic, mostly basaltic, rocks ; even when this is the case, however, 

 the upper portion is usually formed of recent coral limestone. 



In one or two places the sea cliff is interrupted by beaches of 

 coral shingle. The most important of these is at Flying Fish Cove, 

 where it forms a crescent some 500 yards long. Towards the 

 southern end it is composed of sand, but to the northward it 

 becomes coarser and coarser, till about the middle it consists of 

 rolled blocks of coral, and on the foreshore masses of yellowish 

 limestone, apparently part of the talus derived from the cliff 

 behind. At the northern end it becomes finer again. In places 

 the shingle has been cemented into hard, -compact rock, in sheets 

 several inches thick. The top of the beach is about 15 feet 

 above low-tide level, and its slope varies much, being very steep 

 after a northerly or north-easterly gale, and gentler during the 

 prevalence of the trade-wind, Avhen the seji in the cove is qiiiet. 



Behind the beach there is a broad, nearly level platform, com- 

 posed mainly of fragments and blocks of coral, but to some extent 

 also of volcanic and other rock derived from the cliff above. 

 Formerly the whole of this platform was forest - clad, and even 

 now much of the beach down to high-water mark is fringed with 

 a belt of Ironwoods ( Cordid), Waroo (Hib/sctis), and Tourncfortia ; 

 but within this much of the forest has been cleared, fruit-trees 

 (custard apples, limes, etc.) and coconut-palms planted, and a 

 number of substantial houses built. At its northern end this 

 platform is shut in by an inland continuation of the sea cliff 

 (10-20 feet), which still shows traces of wave action; and at the 

 back there rises in a semicircle a cliff covered almost entirely with 

 forest, and towards the middle of the cove towering nearly 500 feet 

 above the platform. 



\Yest AVhite Beach is in some respects similar to Flying Fish 

 Cove, but here the platform is much narrower, and the sea cliff" is 

 continued behind it ; above this cliff there is a wide terrace, as on 



