Appendix

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APPENDIX.

CONTAINING A DETAILED DESCRIPTION OF
THE REEFS AND ISLANDS IN PLATE III.

In the beginning of the last chapter
I stated the principles on which the
map is coloured.  There only remains
to be said, that it is an exact copy
of one by M. C. Gressier, published
by the Depot General de la Marine, in
1835.  The names have been altered
into English, and the longitude has
been reduced to that of Greenwich. 
The colours were first laid down on
accurate charts, on a large scale.  The data, on which the volcanoes
historically known to have been in action, have been marked with
vermillion, were given in a note to the last chapter.  I will commence
my description on the eastern side of the map, and will describe each
group of islands consecutively, proceeding westward across the Pacific
and Indian Oceans, but ending with the West Indies.

The WESTERN SHORES OF AMERICA appear to be entirely without
coral-reefs; south of the equator the survey of the "Beagle", and north of
it, the published charts show that this is the case.  Even in the
Bay of PANAMA, where corals flourish, there are no true coral-reefs, as I
been informed by Mr. Lloyd.  There are no coral-reefs in the
GALAPAGOS Archipelago, as I know from personal inspection; and I believe
there are none on the COCOS, REVILLA-GIGEDO, and other neighbouring islands.
CLIPPERTON rock, 10 deg N., 109 deg W., has lately been surveyed by Captain
Belcher; in form it is like the crater of a volcano.  From a drawing
appended to the MS. plan in the Admiralty, it evidently is not an atoll.
The eastern parts of the Pacific present an enormous area, without any
islands, except EASTER, and SALA, and GOMEZ Islands, which do not appear to
be surrounded by reefs.

THE LOW ARCHIPELAGO.

This group consists of about eighty atolls: it will be quite superfluous
to refer to descriptions of each.  In D'Urville and Lottin's chart, one
island (WOLCHONSKY) is written with a capital letter, signifying, as
explained in a former chapter, that it is a high island; but this must be a
mistake, as the original chart by Bellinghausen shows that it is a true
atoll.  Captain Beechey says of the thirty-two groups which he examined (of
the greater number of which I have seen beautiful MS. charts in the
Admiralty), that twenty-nine now contain lagoons, and he believes the other
three originally did.  Bellinghausen (see an account of his Russian voyage,
in the "Biblioth. des Voyages," 1834, page 443) says, that the seventeen
islands which he discovered resembled each other in structure, and he has
given charts on a large scale of all of them.  Kotzebue has given plans of
several; Cook and Bligh mention others; a few were seen during the voyage
of the "Beagle"; and notices of other atolls are scattered through several
publications.  The ACTAEON group in this archipelago has lately been
discovered ("Geographical Journal", volume vii., page 454); it consists of
three small and low islets, one of which has a lagoon.  Another lagoon-island
has been discovered ("Naut. Mag." 1839, page 770), in 22 deg 4' S.,
and 136 deg 20' W.  Towards the S.E. part of the group, there are some
islands of different formation: ELIZABETH Island is described by Beechey
(page 46, 4to edition) as fringed by reefs, at the distance of between two
and three hundred yards; coloured red.  PITCAIRN Island, in the immediate
neighbourhood, according to the same authority, has no reefs of any kind,
although numerous pieces of coral are thrown up on the beach; the sea close
to its shore is very deep (see "Zool. of Beechey's Voyage," page 164); it
is left uncoloured.  GAMBIER Islands (see Plate I., Figure 8), are
encircled by a barrier-reef; the greatest depth within is thirty-eight
fathoms; coloured pale blue.  AURORA Island, which lies N.E. of Tahiti
close to the large space coloured dark blue in the map, has been already
described in a note (page 71), on the authority of Mr. Couthouy; it is an
upraised atoll, but as it does not appear to be fringed by living reefs, it
is left uncoloured.

The SOCIETY Archipelago is separated by a narrow space from the Low
Archipelago; and in their parallel direction they manifest some relation to
each other.  I have already described the general character of the reefs of
these fine encircled islands.  In the "Atlas of the 'Coquille's' Voyage"
there is a good general chart of the group, and separate plans of some of
the islands.  TAHITI, the largest island in the group, is almost
surrounded, as seen in Cook's chart, by a reef from half a mile to a mile
and a half from the shore, with from ten to thirty fathoms within it.  Some
considerable submerged reefs lying parallel to the shore, with a broad and
deep space within, have lately been discovered ("Naut. Mag." 1836, page
264) on the N.E. coast of the island, where none are laid down by Cook.  At
EIMEO the reef "which like a ring surrounds it, is in some places one or
two miles distant from the shore, in others united to the beach" (Ellis,
"Polynesian Researches," volume i., page 18, 12mo edition).  Cook found
deep water (twenty fathoms) in some of the harbours within the reef.  Mr.
Couthouy, however, states ("Remarks," page 45) that both at Tahiti and
Eimeo, the space between the barrier-reef and the shore, has been almost
filled up,--"a nearly continuous fringing-reef surrounding the island, and
varying from a few yards to rather more than a mile in width, the lagoons
merely forming canals between this and the sea-reef," that is the
barrier-reef.  TAPAMANOA is surrounded by a reef at a considerable distance
from the shore; from the island being small it is breached, as I am informed
by the Rev. W. Ellis, only by a narrow and crooked boat channel.  This is the
lowest island in the group, its height probably not exceeding 500 feet.  A
little way north of Tahiti, the low coral-islets of TETUROA are situated;
from the description of them given me by the Rev. J. Williams (the author
of the "Narrative of Missionary Enterprise"), I should have thought they
had formed a small atoll, and likewise from the description given by the
Rev. D. Tyerman and G. Bennett ("Journal of Voyage and Travels," volume i.,
page 183), who say that ten low coral-islets "are comprehended within one
general reef, and separated from each other by interjacent lagoons;" but as
Mr. Stutchbury ("West of England Journal," volume i., page 54) describes it
as consisting of a mere narrow ridge, I have left it uncoloured.  MAITEA,
eastward of the group, is classed by Forster as a high encircled island;
but from the account given by the Rev. D. Tyerman and G. Bennett (volume
i., page 57) it appears to be an exceedingly abrupt cone, rising from the
sea without any reef; I have left it uncoloured.  It would be superfluous
to describe the northern islands in this group, as they may be well seen in
the chart accompanying the 4to edition of Cook's "Voyages," and in the
"Atlas of the 'Coquille's' Voyage."  MAURUA is the only one of the northern
islands, in which the water within the reef is not deep, being only four
and a half fathoms; but the great width of the reef, stretching three miles
and a half southward of the land (which is represented in the drawing in
the "Atlas of the 'Coquille's' Voyage" as descending abruptly to the water)
shows, on the principle explained in the beginning of the last chapter,
that it belongs to the barrier class.  I may here mention, from information
communicated to me by the Rev. W. Ellis, that on the N.E. side of HUAHEINE
there is a bank of sand, about a quarter of a mile wide, extending parallel
to the shore, and separated from it by an extensive and deep lagoon; this
bank of sand rests on coral-rock, and undoubtedly was originally a living
reef.  North of Bolabola lies the atoll of TOUBAI (Motou-iti of the
"'Coquille's' Atlas") which is coloured dark blue; the other islands,
surrounded by barrier-reefs, are pale blue; three of them are represented
in Figures 3, 4, and 5, in Plate I.  There are three low coral-groups lying
a little E. of the Society Archipelago, and almost forming part of it,
namely BELLINGHAUSEN, which is said by Kotzebue ("Second Voyage," volume
ii., page 255), to be a lagoon-island; MOPEHA, which, from Cook's
description ("Second Voyage," book iii., chapter i.), no doubt is an atoll;
and the SCILLY Islands, which are said by Wallis ("Voyage," chapter ix.) to
form a GROUP of LOW islets and shoals, and, therefore, probably, they
compose an atoll: the two former have been coloured blue, but not the
latter.