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APPENDIX. 
of coral, and although no regular reefs exist, yet the shore 
is in many places lined by coral rock, so that a boat 
grounds on this formation. Hence these islands ought 
perhaps to come within the class of fringed islands and be 
coloured red ; but as I am determined to err on the cautious 
side, I have left them uncoloured. Dana infers (Corals 
and Coral Islands, p. 325), from their steepness and deeply 
indented outline, that they have subsided. 
Cook ok Hakvey and Austral Islands. — Palmerston 
Island is minutely described as an atoll by Captain Cook 
during his voyage in 1774 ; it is coloured blue. Aitutaki 
was partially surveyed by the Beagle (see map accompany- 
ing Voyages of Adventure and Beagle) ; the land is hilly, 
sloping gently to the beach ; the highest point is 360 feet ; 
on the southern side, the reef projects five miles from the 
land : off this point the Beagle found no bottom with 270 
fathoms : the reef is surmounted by many low coral-islets. 
I am informed by the Eev. J. Williams, that within the 
reef the water is exceedingly shallow, not being more than 
a few feet deep ; nevertheless, from the great extension of 
the reef into a profoundly deep ocean, this island probably 
belongs, on the principle lately adverted to, to the barrier 
class, and I have coloured it pale blue, although with much 
hesitation. — Manouai or Harvey Island : the highest point 
is about 50 feet : the Rev. J. Williams informs me that 
although the reef lies far from the shore, it is less distant 
than at Aitutaki, but the water within the reef is rather 
deeper : I have likewise coloured this island pale blue, but 
with many doubts. — Round Mitiaro Island, as I am in- 
formed by Mr. Williams, the reef is attached to the shore ; 
coloured red. — Mauki, or Maouti : the reef round this 
island (under the name of Parry Island in the Voyage of 
H.M.S. Blonde, p. 209) is described as a coral flat, only 
50 yards wide, and two feet under water. This statement 
has been corroborated by Mr. Williams, who calls the reef 
