290 CORAL AND ATOLLS 



buttresses thrown out about the bottoms of their trunks. 

 These buttresses are in the form of large thin wings, which taper 

 to the trunk above, and below form a series of compartments, 

 like stalls in a circular stable. Within these stalls much earth 

 is held fast by the interlacing of smaller roots, and when such 

 a tree is uprooted, and set adrift to sea, it carries its earth with 

 it. It may carry it for very great distances, and I have seen 

 a " buttressed " tree come ashore in the atoll, from whose base 

 a wheelbarrow-load of fine red earth might have been collected. 

 It must be remembered that such an incident is notable in a 

 place where there is no " earth," save coral reduced to sand, 

 and decomposed vegetation in very small quantities. From 

 the roots of such a tree I have taken small stones, and these 

 are rarities in a land where no stones exist. It is certain that 

 such a tree would have many tenants when it started on its 

 voyage, and it is not unlikely that some would have the good 

 fortune to survive the passage. Its advent offers an explana- 

 tion for the presence of Typhlops hraminus — a small snake with 

 an underground habit — in the atoll. 



Many other sea-cast objects are stranded on the barrier. 

 The hard seeds of many plants are washed up on the beaches, 

 and these are potential colonists of the vegetable world. Gum 

 resins float to the islands in large masses, and in the heat 

 of the sun they melt upon the barrier rocks. Timbers of 

 ships, often with copper nails still held fast, tell the tale of 

 wrecks, and the ships that do not come to port. Pumice, in 

 all sizes and shapes, is for ever touring these seas, and in parts 

 of the islands it forms a considerable portion of the beaches ; 

 most of the pumice that comes to the atoll to-day is still the 

 remains of that great upheaval of 1883, when the eruption 

 of Krakatua altered the whole of the topography of the 

 Sunda Straits. This pumice has been touring the ocean for 

 over twenty years, and still, in the Sunda Straits, some set of 

 current will send whole masses to sea, and a ship will steam for 

 half an hour through the bobbing white balls of pumice which 

 are launched upon an indefinite, and an irresponsible, journey. 



In the islands there is a pumice more ancient than this 



