242 GEOLOGICAL CHANGES W# THE EAR 
throws great light on tiicse Kiirprisir.g 
nature. 
prodoC^‘ 
This little island, or rather the surronn^ 
which is three or four miles long 
soutli-cast winds. It 
ippcars to be increasing botli_>‘’^ ji 
distant period of 
cnmference, but 
and extent. At no 
affords sheltf''.j^ |)t 
is scarcely more than 
very 
one of those banks produced by the washing f 
reefs alib''^ " , 
like 
and broken coral, of which most 
and those of Torres’ Strait a great many, 
are in different stages of progress ; some, 
become islands, but not yet habitable; soff-O 
high-water mark, but destitnts of veptation; ''' 
are overflowed with every remrning tide. 
- • * * 
y 
■ It seems to me, that, v. fien the animalcules fjf 
tlic corals at the bottom of the ocean, cease to 
structures adhere to each other, by virtue 
glutinous remains within, or of some property m y 
and the interstices being gradually filled up J 
and broken pieces of coral washed by the sea, 
adhere, a mass of rock is at length formed. ^ ^ 
of these animalcules erect their habitations 
rising bank, luid die in their turn, to 
icuky^ il’ 
principally to elevate. 
tliis monument of ibeitT.wii'. 
to work pci'pendicu 
instinct 
il’.V 
labours. The care taken 
early stages, w'ould mark a surprising n 
diminutive creatures. Their wall ot coral, j,] 
jn situations where the winds are constant, be'>’n [jicli 
the surface, aftbrds a shelter, to leeward ^ 
hifant colonies may be safely sent Ibrtli, and^^^[,c'^ 
instinctive foresight it seems to be owing, 'n^_ J 
ward side of a reef d.xposcd to the open sea,^ 
if not always, the highest part, and rises f’A 
dicular, sometlme.s from' the depth ol' 200> ? 
many more fathoms. To be constantly covered 
seems necessary to tlie existence of tlie nnni ^ ijcy 
they do not work, except in holes upon tlie v / 
low-water mark ; but the coral sand and n 
remnants thrown up by the sea adhere to 
form a solid mass with it, as high as the con 
reach. That elevation surpassed, the futut ly 
being rarely covered, lose their adhesive 
