THE PACIFIC OCEAN* 
221 
that they have been thrown up by earthquakes, and are the 1777. 
effect of internal convulfions of the globe. A third opi- » A ^ nL . 
nion, and which appears to me as the moft probable one, 
maintains, that they are formed from fhoals, or coral banks, 
and, of confequence, increafing. Without mentioning the 
feveral arguments made ufe of in fupport of each of thefe 
fyftems, I fhall only defcribe fuch parts of Palmerfton’s 
Illand, as fell under my own obfervation when I landed 
upon it. 
The foundation is, every where, a coral rock; the foil is 
coral fand, with which the decayed vegetables have, but in 
a few places, intermixed, fo as to form any thing like mould. 
From this, a very fbrong prefumption may be drawn, that 
thefe little fpots of land, are not of very ancient date, nor 
the remains of larger illands now buried in the ocean. For, 
upon either of thefe fuppolitions, more mould mull have 
been formed, or lome part of the original foil would have 
remained. Another circumftance confirmed this doctrine 
of the increafe of thefe illots. We found upon them, far 
beyond the prefent reach of the fea, even in the moft vio¬ 
lent ftorms, elevated coral rocks, which, on examination, 
appeared to have been perforated, in the fame manner that 
the rocks are, that now compofe the outer edge of the reef. 
This evidently fhews, that the fea had formerly reached fo 
far; and fome of thefe perforated rocks were almoft in the 
centre of the land. 
But the ftrongeft proof of the increafe, and from the 
caufe we have afligned, was the gentle gradation obferv- 
able in the plants round the fkirts of the illands; from 
within a few inches of high-water mark, to the edge of the 
wood. In many places, the divifions of the plants, of dif¬ 
ferent growths, were very diftinguilhable, efpecially on the 
3 lee, 
