_SEYCHELLE AND AMIRANTE ISLANDS._
Our voyage from Port Darwin to Singapore took place during the interval
of calms which separates the north-west and the south-east monsoons,
so that we were enabled to steam the entire distance of 2,000 miles
in smooth water. Our course lay among the islands of the Eastern
Archipelago. On the 5th of November we sighted Timor Island, and on the
following morning passed to the northward of its eastern extremity, and
then steered westward, having Timor on our port hand, and the small
island of Wetter to starboard. From that date, the chain of islands
which extends in a north-west direction from Timor right up to the
Malay Peninsula was continually in sight. After dusk on the 7th, we saw
away on our port beam, and towering up into the blue and starlit sky,
the conical mountain which forms the island of Komba. On the 10th, as
we passed to the northward of Sumbawa, we had a fine view of Tambora,
a great volcanic pile 9,040 feet in height. On the same day a handsome
bird of the Gallinula tribe flew on board, and came into my possession.
On the following day a large swift of the genus _Chætura_ shared the
same fate. On the morning of the 12th we passed through the strait
which separates the islands of Sapodie and Madura, and as we emerged
from its northern outlet found ourselves in the midst of a large fleet
of Malay fishing boats, of which no less than seventy were in sight
at one time. These boats were long narrow crafts, fitted with double
outriggers, and having lofty curved bows and sterns. They carried a
huge triangular sail, which, when going before the wind, is set right
athwart-ships with the apex downwards, and when beating seemed to be
used like a reversible Fiji sail. On November 17th we passed through
the long strait which lays between the islands of Banka and Sumatra,
and on the afternoon of the following day dropped our anchor in the
roadstead of Singapore.
We made a stay of two and a half months at the great commercial city
of Singapore, and for the greater part of the time our ship lay at
the Tanjon Paggar dockyard, where she underwent a thorough overhaul,
while officers and men had abundant opportunities for relaxation and
amusements.
On February 5th, 1882, we again got under way, and quitting the
eastern Archipelago by the Straits of Malacca, steered for Ceylon. On
the 10th of February, in latitude 6° 15′ N., longitude 93° 30′
E., we passed through several remarkable patches of broken water,
resembling "tiderips." There was a light northerly breeze, and the
general surface of the sea was smooth, so that these curious patches
could be distinctly seen when a couple of miles ahead of us, and as we
entered each one the noise of tumbling foaming waters was so loud as to
attract one's attention forcibly, even when sitting down below in the
ward-room. The patches were for the most part disposed in curves and
more or less complete circles of half-a-mile in diameter, so that at a
distance they bore a strong resemblance to lines of breakers. Soundings
were taken, but no inequality in the sea-bed was observed sufficient
to account for them. They were most probably due to circular currents
revolving in opposite directions, and producing the broken water at
their points of contact.
We stopped for two days, February the 17th and 18th, at Colombo, the
capital of Ceylon, and then steered for the "Eighth Degree Channel,"
north of the Maldive Islands, after passing through which we shaped a
straight course for the Seychelle Islands.
On the morning of the 4th of March land was reported right ahead;
but as we soon found out with our glasses, all that was really visible
above the horizon was a big tree, which by an optical delusion appeared
to be of a prodigious size, and on account of the absence of the usual
appearance of land was thought by some of us to be only a sail. We
were at this time about ten miles to the north-east of Bird Island,
the most northerly of the Seychelle Group. About midday we anchored in
seven fathoms off the western end of the island, some dozen or so large
gannets coming off to meet us, and hovering inquisitively about the
ship.
[Illustration: "TRAVELLERS' TREES" IN GARDENS AT SINGAPORE. _To face p.
210._]
Soon after, a party of officers, including myself, proceeded to
land. On touching the beach we were met by a pair of negroes, who,
we learned, formed the entire human population of the island. They
occupied some wretched huts which had been hitherto screened from our
view by a dense thicket of bushes, which forms a fringe around the
margin of the island, and gives it, from the anchorage, the delusive
appearance of being well wooded.
Their occupation consisted in catching and drying fish, and in
salting, for consumption at Mahé, the bodies of sea-birds, which breed
on the island in vast numbers, and which are easily taken on their
nests during the breeding season--now just coming to an end. The
negroes spoke a French dialect, and, whether owing to their habitual
taciturnity, or to linguistic difficulties on our part, we could not
succeed in extracting much information from them. We gathered, however,
that turtle visited the island for breeding purposes, but not at this
time of the year.
Bird Island is half-a-mile long, and a quarter of a mile in width,
being thus more or less oval in outline. It is formed entirely of
coral, and is margined all round with white glistening beaches of
calcareous sand. Outside this extends a fringing reef, which forms a
submerged platform, on which there is some three or four fathoms of
water, and which has a mean width radially of about a quarter of a
mile. There is no encircling barrier reef, while the soundings are
so regular as to exclude the existence of coral knolls. The general
surface of the island is quite flat, and has a mean elevation above
the sea-level of about eight feet. Immediately within the sandy beach
above mentioned is a raised inner beach composed of blown sand and
lumps of coral, on which flourishes a belt of low green _Tournefortia_
bushes. After traversing this, one walks over a rugged plain of
honeycombed coral rock, the interstices of which are in some places
filled with sand and vegetable mould, which supports a more or less
general mantle of scrubby grass, interspersed with several introduced
plants gone wild. Among these were cotton, sugarcane, papaws, yams,
gourds, cocoa-nuts, and perhaps a few others. It appeared that none
of these had been found to thrive, which no doubt accounts for their
present neglected state. We now ascertained that the large tree which
had attracted our attention from the offing was a _Casuarina_, of which
there were altogether two or perhaps three on the island.
There were no land-birds. Sea-birds, however, were very abundant,
and seemed in many ways to have partially adapted themselves to the
habits of their terrestrial congeners. The sand and light soil,
which in some places occupied the cavities in the coral rock, were
everywhere excavated by the burrows of petrels, so that within an
area of four square yards one might count as many as a dozen. There
were also smaller burrows--not admitting the hand--in one of which I
captured a land-crab. Walking over the island--small as it was--proved
to be very fatiguing and aggravating, for after one had extracted a
bruised ankle from some treacherous hole in the coral, which the long
grass concealed, the next step, taken with misplaced confidence on
an inviting-looking patch of sand, would probably put the other foot
through the frail roof of a petrel burrow, into which it would descend,
to the alarm and indignation of its proper tenant, no less than to the
mortification of the explorer.
Many gannets were breeding on the island. I approached a large brown
bird as it sat on its nest, and, being anxious to obtain a specimen of
the egg, endeavoured to frighten it off by going within a couple of
yards and shouting riotously. The bird, however, did not seem to heed
me. I then tried stones, but with no better result. Eventually I had
to resort to sterner measures, which I forbear to mention, but which
proved satisfactory. The nest consisted of a few twigs and pieces of
withered grass, placed on the surface of the hard coral.
The terns, of which there were great numbers, either standing quietly
on the ground in flocks or perched singly on the low bushes, had just
concluded their breeding labours, and I found a few abandoned eggs.
Their nests were similar to those of the gannet above mentioned.
Consorting with the terns and gannets were multitudes of white egrets,
stalking about unconcernedly in the long dry grass, or perching in
a dreamy sort of way on the topmost twigs of the bushes. All these
birds, terns, gannets, and egrets, seemed to be quite as much at home
when perching on the bushes or standing in the grass as in their usual
attitude on the wing. They seemed indeed very loth to fly, and after
being rudely disturbed soon settled down again. The beaches of the
weather or east side of the island were studded with great flocks of
turnstones and curlews, with which were a few oyster-catchers, and
soaring high overhead was a great flock of frigate birds.
At an early hour on the following morning (March 5th) we were again
under way, and steering towards Port Mahé, which lies sixty miles to
the southward of Bird Island. The dredge had been laid out from the
stern of the ship soon after anchoring, and on hauling it up just
before weighing, one of the tangles was found to have attached to it
a large slab of dead coral, which contained a great variety of forms
of life. There were on its surface several detached masses of growing
Corals, comprising five or six different species, and an equal number
of Polyzoa, besides some Nullipores and Millepores. In the interstices
were several species of shells, worms, and Ophiurids, and two or three
species of sponge.
At three o'clock in the afternoon we anchored at Mahé, the chief island
of the Seychelle Group.
Seychelles, a term which is used to comprise the group of eighty
islands, has been a British colony since the year 1794, when it was
taken from the French by force of arms. Most of the land is in the
possession of descendants of the old French settlers, men who have
the reputation of being devoid of enterprise, and of squandering the
produce of their land in habits of dissipation. We were told that
among the upper classes there were only about six Englishmen in the
group, including the governor, secretary, and doctor, etc. By a census
taken in 1880, the total population was 14,035, of which 2,029 was
represented by African negroes. The population of the chief island,
Mahé, alone amounted to 11,393, so that there remains less than 3,000
to be divided among the remaining islands of the Group. The total has
since been increasing, owing to a stream of immigration having set in
from Mauritius, where there exists a commercial depression; so that at
the time of our visit it was said to amount to 18,000.
I think that to most people Seychelles is principally known as the
home of that eccentric palm, the double cocoa-nut, or "Coco de Mer."
Its range is indeed very restricted, being, in fact, limited to
Praslin,--one of the smaller islands of the Group,--and even there it
only grows in one particular valley. A few have been introduced into
Mahé, and great care is now being taken in order to promote their
extension. There was a handsome specimen of the female tree growing in
the grounds of Government House, which was shown to me by Mr. Brodie,
the courteous Secretary to the Council. The tree being unisexual,
isolated specimens can only be made fruitful by artificial means. In
the present instance, the tree being over thirty years old, and in the
proper condition for impregnation, Mr. Brodie had taken the trouble
to obtain from Praslin the reproductive portion of a male plant,
which he had placed over the immature fruits on the female tree. The
male tree bears a long thick spike, studded with minute flowers, the
pollen from which must be shaken over the female flowers, in order to
insure impregnation. The tree at Mahé was about twenty feet high, but
I was informed by Mr. Brodie that fully grown trees in the island of
Praslin attain a height of a hundred feet. The mature nuts if left on
the ground readily germinate. The outer hard covering splits at the
sulcus of the nut, and from thence shoots out a rhizome, which after
extending underground for a few feet gives origin to the future stem
and rootlets, which proceed respectively upwards and downwards from the
termination of the rhizome. The Coco de Mer is an article of trade, a
good many being brought over annually to Mahé, where some are sold to
visitors as curiosities, while the remainder are shipped to the Red
Sea ports to be sold to the Arabs, who have a profound belief in their
medicinal properties.
In the gardens of Government House were also two fine examples of
the celebrated Land Tortoise of Aldabra, an animal which, although
indigenous in Aldabra Island alone, has of late years been introduced
into many of the neighbouring islands. The pair at Mahé were male and
female, and weighed respectively about four hundred and five hundred
pounds. The male seemed to have no difficulty in bearing a man upon his
back. At the time of our visit the female had just commenced to lay,
depositing her eggs in holes which she excavated in the damp soil, and
carefully filled in.
From a commercial point of view, the Seychelle Islands are now in
a transition state. The cocoa-nut industry has of late years been
unprosperous, mainly owing to the ravages of a worm which invades the
roots and stem of the cocoa-nut trees, and causes them to dwindle and
perish. The produce of oil has consequently been so reduced, and the
freight charges continue to be so high, on account of the absence of
steamship competition, that only a small margin of profit is left to
the planter. This failure of the cocoa-nuts has led to a revival
of the old spice industry, which, under the early French settlers,
was at one time deemed likely to vie with that of the Moluccas. On
looking over the Blue Book Report, I find that in the year 1880 there
were 12,000 acres of land planted with cocoa-nuts, which in spite of
the recent blight continue to be the staple product of the Group. In
the same year there were one hundred and fifty acres devoted to the
growth of vanilla; a hundred acres were planted with cacao bushes,
and a hundred and fifty were producing cloves; besides a large extent
of land bearing coffee plantations. Both the Liberian and the common
coffee plants have been introduced, and found to grow remarkably
well. Vanilla, in particular, seems to find a congenial home in the
Seychelle Islands, and, during our short visit to the colony, we
gathered that the future hopes of the settlers were mainly centred
upon the successful cultivation of this plant. It grows rapidly, and
although the flowers require to be fertilized by hand, yet this process
is so readily performed that beans of large size and excellent quality
are produced. It is as yet only grown in a small way, most of the
vanilleries, as these plantations are called, covering only an extent
of about five acres. It is estimated that each plantation of this size
represents an annual produce of two hundred and fifty pounds' weight of
vanilla beans. We inspected some plants in the garden of Dr. Brookes,
an old resident, and noticed that the beans averaged eight inches in
length, and were otherwise well formed. He told us that he had been
most successful in the curing of these beans, and expected that when
they became well known they would command a large price in the European
markets, and that eventually vanilla would become the staple produce of
the Seychelle Islands.
The method employed at Seychelles for the expression of the oil from
the internal white lining of the cocoa-nut struck me as being novel
and primitive; and as it is said to be very efficient, I shall try to
give an intelligible description of a crushing mill and its mode of
construction. In principle it is a sort of gigantic pestle and mortar,
in which the pestle is made to perform a movement of circumduction,
and whilst doing so to rotate against the sides of the mortar, where
the crushing process is effected. A large-stemmed tree of very hard
wood having been cut down, so as to leave about three feet of the trunk
projecting above the ground, a bucket-shaped cavity is excavated in
the stump. A heavy round spar about ten feet in length is stepped into
this cavity, and is made to incline forcibly to one side by means of
a wooden outrigger, which is supported by a rope attached to the head
of the spar, and is weighted with heavy stones placed at its outer
extremity. The inner end of the outrigger is fitted with wide U-shaped
jaws, which engage in a collar scored in the tree stump just above its
point of emergence from the ground, while the rope-lift which supports
its outer extremity is so attached to the head of the upright spar that
the outrigger may be free to move radially about the stump at the same
time that the upright spar rolls round on its long axis, as it presses
heavily against the sides of the trough. Finally a small hole is bored
laterally, so as to reach the bottom of the cavity in the tree stump,
and into this is thrust a short bamboo tube to act as an oil-tap.
The broken-up copra is thrown in around the lower extremity of the
upright spar, and a bullock is set to work to drag round the outrigger
arrangement. The only attendance required is that of a small boy to
feed the wooden trough with copra, and occasionally to throw stones so
as to accelerate the otherwise lazy motion of the bullock. In the mill
which I examined the oil was flowing steadily from the bamboo tap in a
clear limpid stream.
We dredged several times with the steam-cutter in the channel between
Mahé and St. Anne's Island, and also in St. Anne's Channel. The
depth of water in these channels ranged from four to twelve fathoms,
and the bottom consisted of sand and coral. The fauna was abundant,
and comprised Shells of the genera _Murex_, _Arca_; large grey
Holothurians; Echinoderms of four or five species; Crustacea of the
genera _Thalamita_, _Galathea_, _Porcellana_, _Atergatis_, _Scylla_,
_Alpheus_, etc., and a large variety of Corals and Polyzoa.
One of the most conspicuous objects about the foreshore at Port Mahé
is a curious fish of the genus _Periophthalmus_, which may be seen not
only jumping about the dry mud flats at low water, but also climbing
up the rugged vertical faces of the blocks of granite of which the
sea-wall and pier are formed. It is very difficult indeed to catch
one, as I have good reason to know. Associated with them were several
species of crabs, among which I recognized representatives of the
genera _Macrophthalmus_, _Gelasimus_, _Grapsus_, and _Ocypoda_.
The Seychelles are peculiar in being the only small tropical oceanic
islands of granitic structure. All the others, excepting St. Paul's
Rocks, are either of volcanic or coral formation. The rock about Port
Mahé is a syenitic granite, in which the mica of ordinary granite is
replaced by hornblende. In some cases the felspar is coloured blue,
in others reddish, and in every instance it occurred in large coarse
crystals. The soilcap was a reddish pasty clay, of great thickness. In
one of the road cuttings near the settlement a section of this clay
fully ten feet in depth was exposed.
We left Mahé on the 14th of March, and on the following day anchored
off a small coral islet, the northernmost of the Amirante Group.
This, with another similar islet adjoining, constitute the African
Islands. A party of surveyors immediately landed in order to fix on a
suitable place for taking midnight observations of the stars, and I
had soon afterwards an opportunity of landing to explore. The islet
is two hundred yards long, by about sixty yards in width, is more or
less elliptical in outline, low, and flat, and for about three-fourths
of its circumference is girt by a smooth beach of coral sand, on the
surface of which I noticed a prodigious number of _Orbitolites_ discs.
The northern end of the islet is composed of upraised coral sandstone,
which has been grooved and honeycombed into various fantastic shapes,
so that for walking over it presents quite as unsatisfactory a
surface as volcanic clinker. All the central part of the islet within
the inner drift beach is covered with scrubby grass and low bushes
of the same character as those at Bird Island. There were one or two
young shoots of a _Barringtonia_; but nothing else in the shape of an
arborescent plant. Among the dead shells, light driftwood, and bleached
sponges and coral blown up on the inner beach, I noticed some of the
familiar rhomboidal fruits of a _Barringtonia_.
[Illustration: "COPRA" CRUSHING-MILL IN USE AT SEYCHELLES (_p. 217_).
_To face p. 218._]
There were no land-birds. The sea-birds were identical with those of
Bird Island. Young unfledged gannets were waddling about among the
bushes, and as regards the other birds, their nesting season also
seemed to be over. I did not notice any petrel burrows, but everywhere
near the beach were the burrows of a littoral crab, a species of the
genus _Ocypoda_. On the rocks at the northern extremity were multitudes
of the widely distributed _Grapsus variegatus_. When chasing them over
the rocks of the foreshore, I observed that they were reluctant to take
to the water, but preferred to keep clear of me by scampering away
over the coral further inshore. The cause of this strange behaviour on
their part soon became apparent; for the rock-pools about the foreshore
were tenanted by savage grey eels, ranging in length from two to three
feet, and I saw that the moment an unlucky crab was forced to enter
one of these pools, he was immediately snapped up and devoured. I was
surprised to see the coolness with which an eel would every now and
then raise its head above the water in which it lay, and look about
over the adjacent rocks to see if any crabs were near. On starting an
eel from its hiding place, it would scuttle with astonishing rapidity
over the low rocks which separated it from the water's edge, so that
it was no easy matter to secure one without the aid of a gun. Shooting
them, as they wriggled off in this way, was rather good sport.
The island is evidently visited by turtle during the breeding season,
for we saw several of the excavations in which they were in the habit
of depositing their eggs.
We got under way at seven o'clock in the morning, and after running
several lines of soundings over the outer edge of the Amirante bank,
steamed over to Eagle Island, which lies about thirteen miles to the
southward of African Islands, and again dropped anchor.
Eagle Island is somewhat oval in shape, and is a quarter of a mile long
by one-eighth in breadth. It is entirely of coral formation, is low and
flat, is covered with a thick growth of stunted bushes, and in other
physical features is much the same as the African Islands. There was,
however, an increase in the fauna in the shape of a small red-legged
partridge, which was very abundant, and afforded us some good shooting.
Owing to the thickness of the scrub, and weedy undergrowth of grasses,
ill-conditioned gourds and calabashes, it was found very difficult to
recover the dead birds, so that I fear there were a good many shot
which were never bagged. The only other land-birds on the island were
domestic fowls gone wild. Of these we saw an old cock and hen, and some
three or four chickens, which, on being disturbed, rose and took to
flight like pheasants.
In the interior of the island, among a tangled scrub of bushes, we
found the remains of an old stone-built hut, which from the solidity
of its four walls would seem to have been originally intended as a
permanent dwelling for Europeans.
I took several specimens of a small species of lizard, and also some
of the tiny spherical eggs of the same. I stowed away the eggs in a
matchbox with some sand, and left it open on the table of the deckhouse
on board. After a day or two the young lizards began to break out of
their eggs, and to wander about among the materials on my work-table.
I broke open one egg, and found that the youngster was at once able
to run about. After it had wandered about the table, and up and down
the sides of some bottles standing near, it returned to the matchbox
and remained for a long time hovering about it, as if terrified at the
immensity of the world, and loth to venture away from its former narrow
dwelling.
In some small holes about the centre of the islet we found a land-crab,
apparently similar to that of Bird Island; and from some large burrows
issued the peculiar groaning sounds made by the night petrel.
One of the most singular features in the zoology of the islet was the
abundance of a hermit crab,--occupying a _Neritina_ shell,--which was
to be seen and heard creeping over the stems and branches of the bushes
in all directions. They seemed for the time to have entirely adopted
terrestrial habits.
We got under way again on the morning of the 20th of March, and, after
spending the day in sounding from the ship, steamed up to Darros
Island, and again anchored.
This island is somewhat circular in shape, and has a maximum diameter
of three-quarters of a mile. It is inhabited by a Frenchman and his
wife, who are assisted by nine negro labourers from Mahé. Adjoining
are nine small islets, bearing a rich crop of cocoa-nuts. Darros
Island itself as yet produces next to nothing, but it contains a
large plantation of young cocoa-nuts, which in five or six years will
doubtless be productive. Immediately behind the Frenchman's house, and
affording an agreeable shade, was a handsome grove of _Casuarinas_
about eighty feet in height. They were nineteen years old, as we
subsequently ascertained. Many introduced plants--such as papaws,
cotton, pumpkin, etc.--were growing in a neglected state over the
island.
We dredged from the ship as she lay at anchor in twenty-one to
twenty-two fathoms, over a bottom which was mainly composed of
coral _débris_, and among the living organisms brought up were
three species of stony corals. This circumstance is of interest as
regards the bathymetrical distribution of corals, inasmuch as Dana,
judging from the results of observations made by various authorities,
considers that twenty fathoms may be regarded as the limit in depth
at which reef-forming corals live. Polyzoa were numerous. I noticed
representatives of the genera _Retepora_, _Crisia_, _Eschara_,
_Cellepora_, _Lepralia_, and _Myriozoum_. There were also some examples
of _Sertularia_ and other flexible hydroids.
Our gropings over the platform of fringing reef, which formed the
foreshore at low water, resulted in the acquisition of several species
of holothurians. Among these was a large _Synapta_, which was abundant,
and a very tough-skinned holothurian--of the genus _Moliria_--provided
with organs resembling teeth at its posterior extremity.
On March 23rd we moved over to Poivre Island--a few miles
distant--where we anchored, and remained for part of two days.
Poivre Island was colonized for the first time in the year 1820. It
is now the property of a Frenchman residing at Paris, and is managed
by his agent, a Monsieur Bertaut, who, with his wife and family,
and some twenty negroes and their wives, form the population of the
island, altogether amounting to twenty-seven. Of course the staple
produce is cocoa-nut oil, and the island having been planted with
cocoa-nuts at an early period in its history, the trees are in good
condition for bearing, and cover every available spot of ground. Among
the other trees on the island I noticed a _Casuarina_ and a _Ficus_.
Two shrubs were common; one, called the "Bois d'Aimanthe" (_Suriana
maritima_), formed a sort of hedge around the island, and the other was
a _Tournefortia_, which seems to be the first plant to establish itself
on these islands. The fauna included a black-and-white rabbit--of
course introduced--which was very abundant, and some pigeons of a
dark-brown plumage. Pigs and domestic poultry seemed to be largely
favoured by the colonists, and were indeed in a thriving state.
Like all the Amirantes, Poivre Island is low and flat, and is only
exceptional in being the most prosperous island of the group, for which
it is indebted to the zeal of the earlier colonists who planted its
splendid grove of cocoa-nuts. The island is oval in shape, about two
miles in circumference, and it has a broad fringing reef composed of
drift coral and sand, but exhibiting no live corals and very few shells.
We cast anchor off the north-west side of Isle des Roches on the
evening of the 25th of March, and stayed there for four days. This is
the largest island of the Amirante Group, being three and a half miles
long, and having an average width of half-a-mile. It is visible for a
long distance off, on account of its possessing several large groves of
tall _Casuarina_ trees, many of which are one hundred and eleven feet
in height. On the shore, immediately opposite to our anchorage, was the
settlement, which then exhibited a rather desolate appearance, as many
of the houses were in an abandoned condition, most of the inhabitants
having recently gone back to Seychelles. Only two individuals remained,
French creoles, who seemed to have acquired, from their solitary
situation, habits of taciturnity, which they found it difficult to
break through. At all events, we could not succeed in extracting much
information from them. They were well off for supplies, having a large
stock of pigs and poultry, besides fruit and vegetables. Cocoa-nuts had
been planted extensively, but as yet few of these trees were old enough
to bear fruit. At the time of our visit, the natives were engaged in
planting vanilla cuttings about the bases of the casuarina trees, which
furnished excellent supports for the creeper to attach itself to.
The flora was more extensive than that of the other islands. There
was a large-leafed shrub with thick branches like cabbage-stalks,
the _Scævola kœnigii_, which over ran the island. There were
also herbaceous plants of the families _Malvaceæ_, _Solanaceæ_,
_Cinchonaceæ_, and _Convolvulaceæ_. Among the trees I noticed a Ficus,
which, however, may have been introduced; and here I obtained the only
fern met with among the Amirantes, the _Nephrolepis exaltata_; it was
growing near the sea beach at the eastern end of the island.
There were six land-birds: viz., a red-legged partridge, a pigeon,
a large brown finch, and a small yellow-breasted finch, a red-capped
weaver-bird, and a waxbill (?). Of these I could only obtain specimens
of the small finch and the weaver-bird. The yellow-breasted finch
is gregarious, and mostly frequents the tops of the cocoa-nut trees
and the upper branches of the tall casuarinas, where it keeps up an
incessant melody of song, pleasant to the ear in the variety and
succession of the notes, and somewhat resembling the song of the
canary. In the large casuarina grove, near the western end of the
island, I succeeded, but with much difficulty, in procuring some male
specimens of the weaver-bird (_Foudia madagascariensis_). The females
were nesting. I observed one of the latter flying away from the tree
in which its nest was constructed, and from which I had disturbed it.
It differed from the male in having the red-coloured feathers confined
to the head, the rest of the plumage being of a dull brown. The nest
was an oblong affair, having a lateral opening, and was constructed
of a parasitic plant of creeping habit, which the creoles use for
making a substitute for tea. The nest hung from the extremity of a
casuarina branch which projected horizontally. The male bird was to be
seen perched singly on the summits of the large casuarinas, where it
made its presence known by a peculiar and characteristic twittering
note which it emits about four times in a minute. It was very wary,
and difficult to approach within a sixty yards' range, so that it was
only by most careful stalking that I could succeed in bringing down a
specimen. The brown finch was not abundant, and seemed to confine its
range to the plantations of young cocoa-nuts, where it was continually
shifting its perch. The waxbill was a very small bird, which was to be
seen every now and then flitting in large flocks among the maize plants
and low bushes. I was much surprised to find that the four small birds
above mentioned were so very wary, as there were no predatory birds on
the island, and it was unlikely that they had ever been shot at before.
Nevertheless, the motion of raising one's gun at a distance of sixty
yards or more was enough to scare away any of them.
The partridge was identical with that already seen at Eagle and Darros
Islands. The pigeon, which I have included among the list of the birds,
I saw only once. But one of the creoles living on the island told me
that it was an indigenous species, and was quite distinct from the
domestic pigeons which roost about and restrict their range to the
houses and trees about the settlement.
Although this island has been classed as one of the Amirante Group, it
would be more correct to look upon it as distinct and apart from the
main group, inasmuch as the bank on which it rests is separated from
the Amirante bank by a deep water channel eleven miles wide. We sounded
across this channel, and obtained no bottom with one hundred fathoms
of line. Isle des Roches is, moreover, peculiar in forming part of an
atoll, most of which is submerged, and is covered with from two to five
fathoms of water. The circumscribed patch of deep water in the interior
has a depth of about fifteen fathoms.
During the week subsequent to our departure from Isle des Roches, we
anchored successively off the four remaining islets of the group; viz.,
Etoile, Marie-Louise, Des Neufs, and Boudeuse. They are mere cays,
formed of coral and drift sand, and are uninhabited. Owing to the heavy
surf which broke all round their shores, we found it unsafe to land.
With our brief visit to the islets just mentioned our survey of the
Amirante Group came to an end. I will, therefore, before quitting
the subject, make a few general remarks on the group as a whole. The
Amirante Group consists altogether of twenty-one low coral islets,
resting (with the exception of Isle des Roches, which is on a
separate bank) on an extensive coral bank, whose long axis lies in a
north-north-east and south-south-west direction, and is eighty-nine
miles in length, with an average breadth of nineteen miles. It is
included between the limits of 4° 50-1/2′ and 6° 12-1/2′ south
latitude, and 53° 45′ and 52° 50-1/2′ east longitude, and is about
seven hundred miles distant from the nearest part of the East African
coast. Some of the islets and cays of which it is composed, and which
are included in the above enumeration, are so grouped into clusters,
that for all practical purposes the group may be considered as
consisting of nine islets, which have been named African Island, Eagle
Island, Darros Island, Poivre Island, Des Roches Island, Etoile Island,
Marie-Louise Island, Des Neufs Island, and Boudeuse Island. Of these
only three are inhabited; viz., Darros (including the adjoining islet
"St. Joseph," which is occupied by part of the same establishment of
creoles), Poivre Island, and Isle des Roches; the population consisting
of French creoles and negroes imported from Seychelles, who make a
livelihood by cultivating cocoa-nuts, and altogether do not exceed
forty in number. The islets are all low and flat, are formed entirely
of coral and coral-sandstone, and their general surface has an altitude
above high-water mark not exceeding fifteen feet, while in the case of
African Island, the lowest, it is not more than seven feet. Most of
them, however, are conspicuous from a long distance at sea, on account
of their possessing clumps and groves of casuarina trees, which tower
to heights ranging from eighty to one hundred and eleven feet above the
soil, as ascertained by trigonometrical measurement. The casuarinas
at Darros Island, which were eighty feet in height, had been planted
nineteen years prior to the time of our visit by a Frenchman named
Hoyaeux, whom we subsequently met at Providence Island.
All the islets above mentioned possess "fringing reefs," but are
distinguished from the coral islets of the South Pacific, and of the
other parts of the Indian Ocean, by the entire absence of "barrier
reefs." The soundings which we made over the Amirante bank showed a
general uniformity in the contour of its surface; whilst at the same
time there was abundant evidence that the central portions were more
depressed than the margins. Soundings in the latter situation gave
a depth ranging from ten to fourteen fathoms, and as each line of
soundings reached the central depressed area of the bank, a depth of
about thirty fathoms. The islands were for the most part situated near
the margin of the bank, and were in every case surrounded by a zone
of shallow water. Hence it is obvious that if the entire structure
were suddenly to undergo an elevation of about fourteen fathoms, or
eighty-four feet, it would present the appearance of an atoll studded
with comparatively lofty islets, and enclosing a lagoon of still water
sixteen fathoms in depth.
The outer edge of the bank was exceedingly abrupt, for within a
ship's length the soundings changed from ten or fourteen fathoms on
the margin, to no bottom with one hundred fathoms of line immediately
outside the edge. This precipitous character of the reef-edge was found
to be the same throughout its entire extent. At various points over
this area growing corals were obtained at depths ranging from twelve to
twenty-two fathoms, the latter being somewhat greater than the limit
in depth at which it is generally agreed that reef-forming corals can
live. It therefore follows, that if the entire bank were now to subside
bodily at a faster rate than the corals can by their growth raise the
surface upwards, these organisms would soon be immersed below their
natural limit, and would consequently die. But we have no evidence of a
subsidence having occurred, beyond the fact that the bank, as a whole,
bears a resemblance to a submerged atoll, while on the other hand there
are some positive evidences of elevation to be seen in the overlying
islands. At Eagle Island, the general surface--that is to say, all the
land within the inner, or coral-drift beach--is level, and consists of
dead coral _in situ_; so that if denuded of its present covering of
low vegetable growth, it would present much the same appearance that
a broad platform of fringing reef might, if elevated above high-water
mark and allowed to remain exposed to the weather for a few years. The
same is the case as regards the greater part of one of the African
Islands which we visited; while its northern extremity was composed of
upraised coral sandstone, standing _in situ_, and exhibiting excavated
grottoes and jagged pinnacles, resulting from old marine degradation.
It may therefore be inferred that these two islands have been subjected
to a movement of elevation to the extent of at least a few feet at
some period subsequent to the formation of their present reef-coral
surfaces. Again, at Isle des Roches, which, however, it should be
remembered lies on a separate, although adjacent bank, there were
along its south-eastern margin stratified beds of hard coral sandstone
occupying a position above high-water mark, and presenting to seaward
an abrupt eroded face of hard rock which was undergoing degradation,
and was being undermined by the action of the waves on a soft subjacent
stratum. As regards the other islands of the group, I have seen no
evidence of elevation beyond the fact that they are higher than either
African or Eagle Island; one of the most southerly being as much as
fifteen feet above high-water mark. I may add that the absence of
"barrier reefs" throughout the group militates against the probability
of subsidence having taken place. There is, therefore, reason to
believe that the entire group have undergone elevation rather than
subsidence; and if the forces which produced this condition be still
in operation, and continue so until a further elevation of fourteen
fathoms has been effected, there will result an atoll over eighty miles
long by twenty in width, and studded with lofty coral islands, somewhat
resembling the high islands of the south-eastern Paumotus, such as
Elizabeth Island, which Dana describes as being eighty feet in height.
The Amirante Group furnishes an illustration of the generally accepted
position that corals grow more luxuriantly on the weather than on
the lee side of banks and reefs. In this region, a wind, varying in
direction between east and south-east, prevails throughout ten months
of the year, and consequently gives rise to a proportionately constant
surface current; and, on looking at the grouping of the islets, we find
that of the eight which rest upon the same bank, six are situated on
or about its eastern margin, while the remaining two, which are placed
on its south-western side, are comparatively insignificant sand-cays.
Again, Isle des Roches, which rests on a bank to the eastward of the
Amirantes, from which it is separated by a deep-water channel eleven
miles wide, is situated on the eastern, or weather margin of its own
bank--also a partially-submerged atoll.