CORAL ISLANDS. 381 



sometimes there is an opening, admitting a boat or canoe, 

 in the reef, but I never saw or heard of an opening that 

 would admit a ship. 



The reef, or the first origin of these isles, is formed 

 by the animalcules inhabiting the lithophytes. They 

 raise their habitation within a little of the surface of the 

 sea, which gradually throws shells, weeds, sand, small 

 bits of corals, and other things, on the tops of these co- 

 ral rocks, and at last fairly raises them above water ; 

 where the above things continue to be accumulated by 

 the sea, till by a bird, or by the sea, a few seeds of 

 plants that commonly grow on the sea-shore, are thrown 

 up, and begin to vegetate ; and by their annual decay 

 and reproduction from seeds, create a little mould, year- 

 ly accumulated by the mixture with sand, increasing the 

 dry spot on every side ; till another sea happens to carry 

 a cocoa-nut hither, which preserves its vegetative power 

 a long time in the sea, and therefore will soon begin to 

 grow on this soil ; especially as it thrives equally in all 

 kinds of soil ; and thus may all these low isles have be- 

 come covered with the finest cocoa-nut trees. 



The animalcules forming these reefs want to shelter 

 their habitation from the impetuosity of the winds, and 

 the power and rage of the ocean ; but as, within the tro- 

 pics, the winds blow commonly from one quarter, they, 

 by instinct, endeavour to stretch only a ledge, within 

 which is a lagoon, which is certainly entirely screened 

 against the power of both. This, therefore, might account 

 for the method employed by the animalcules in building 

 only narrow ledges of coral rocks, to secure in their mid- 

 dle a calm and sheltered place ; and this seems to me to 

 be the most probable cause of the origin of all the Tro- 

 pical Low Isles, over the whole South Sea. 



