THE CORAL ISLAVDS. SS5 



atioii. In the large island-cliains there are always 

 some single islets, which have the appearance of 

 high land : these lie upon an angle projecting into 

 the sea, are exposed to the surf from two sides, 

 consist, therefore, almost entirely of large blocks 

 of coral, and are destitute of smaller fragments 

 of shells and coral sand to fill up the intervals. 

 They are, therefore, not adapted to support 

 plants requiring a depth of soil, and only afford 

 a basis to high trees, provided with fibrous 

 roots, (as the Piso?iia, Cordia Sebastianay L. 

 Morinda citrifoUay L. and Pandanus odoratissimus, 

 L.) which, at a distance, give to these, always very 

 small, islands the form of a hill. The inner shores 

 of the island, exposed to the surf, consist of fine 

 sand, which is washed up by the tide. Between 

 the small islands, under their protection, and even 

 in the middle of the inner sea, are found smaller 

 species of coral, which seek a quiet abode, form 

 in time, though very slowly, banks, till they at 

 last reach the surface of the water, gradually 

 increase in extent, unite with the islands that 

 surround them, and at length fill up the inner 

 seas ; so that what was at first a ring of islands, 

 becomes one connected land. The islands which 

 are so far formed, retain in the middle a flat place, 

 which is always lower than the wall that surrounds 

 them on the banks ; for which reason pools of wa- 

 ter are formed in them after a continued rain — 

 the only springs and wells they possess. Among the 



