C 39 6 ] 
coral j which fand, being eafied raifed, will be lodged 
at top. When the fand bank is raifed by violent 
dorms, beyond the reach of common waves, it be- 
comes a refling place to vagrant birds, whom the 
fearch of prey draws thither. The dung, feathers, 
6cc. increafe the foil, and prepare it for the recep- 
tion of accidental roots, branches, and feed, caft up 
by the waves, or brought thither by birds. Thus 
ijQands are formed : the leaves and rotten branches, 
intermixing with the fand, form in time a light black 
mould, of which in general thefe iflands confiff, 
more fandy, as lefs woody ; and when full of large 
trees, with a greater proportion of mould. 
Cocoa nuts, continuing long in the fea without 
lofmg their vegetative powers, are commonly to be 
found in fuch iflands ; particularly as they are adapt- 
ed to all foils, whether fandy, rich, or rocky. 
The violence of the waves, within the Trcpicks, 
mud generally be directed to two points, according 
to the monfoons. 
Hence the iflands formed from coral banks muft 
be long and narrow, and lie nearly in a meridional 
direction. For even fuppofmg the banks to be 
round, as they feldom are when large, the fea, 
meeting mod refidance in the middle, mud heave 
up the matter in greater quantites there than towards 
the extremities : and, by the fame rule, the ends 
will generally be open, or at lead lowed. They 
will alfo, commonly, have foundings there, as the 
remains of the bank, not accumulated, will be un- 
der water. 
Where the coral banks are not expofed to the 
common monfoon, they will alter their dire&ion ; 
and 
