DESCRIPTION OF THE EXPEDITION. 4] 
sandbank and a great resort for turtle, to Coin du Mire, the only land and surface reef 
on the south rim of the atoll for 8 miles. We were unable to land upon it, but we 
‘steamed as close to it as we dared and examined it from the rigging. Moresby found it 
grown over with bushes, but now it consists of a small flat about 10 feet above the 
sea-level covered with some clinging green halophilous plant. Around it is a ring of 
rocks evidently broken off a ragged cliff outside, 4 to 6 feet in height. Below this, about 
5 feet above the sea, it appears to rest upon a red-looking terrace, 20 yards in breadth, 
continuous all round except one little patch of sand to the north-west. This again ends in 
a cliff which is undermined in places. There is no trace of any surface-reef nor, indeed, 
of any upgrowth in the vicinity, the bottom beneath us in 5 to 10 fathoms appearing 
very bare and dead. The rock of the island appears to be sand with a certain admixture 
of coral, perhaps tuffe, a slight horizontal stratification being visible in the upper cliff 
and the broken-off masses being more or less squared. The island has without doubt 
washed away materially since Moresby’s survey, and is now evidently occasionally 
completely washed by the spray. In another 60 years it will probably disappear if the 
same process continues, and in yet another 60 no trace of its former existence will 
remain. It suggested itself to us at once as being perchance the remains of a former 
great series of islands and surface-reefs extending between Fouquet and Grande 
Coquillage. If this be so, it follows that Peros is gradually being submerged or 
destroyed, but this is a matter which demands more careful examination later on. 
We reached Yéyé the same evening, and, finding some huts there, decided to camp 
and examine it and its reefs, particularly in connection with the formation cf the coral- 
‘reefs of Peros. Lieut. Hancock was with us, devoting himself to a survey and section 
of the island, and we also had the ‘ Xanthus,’ as we intended, if the weather moderated, 
to visit some of the other islands. Our first object was the examination of Petite Tle 
de Yéyé, a small rocky islet which had been washed up on the reef to the west. It was 
just commencing to show its first vegetation in the shape of three coconuts, which after 
being washed up had germinated (Pl. 7). There were also a few seedlings of manioc 
(Scevola) ; and its shores were strewn with the nuts of takamaka (Calophyllum), and we 
observed those of five other plants as well. Yéyé itself was singularly barren, the greater 
part of its surface being a great tuffe-flat, studded with clumps of Scevola and 
- Tournefortia, looking like laurels with aged rhododendrons pushing out of the same. 
On one part of its shore were growing two bushes of Pemphis acidula, the only place 
where we found it in the Chagos, though in the Maldives it is certainly the most important 
and widely distributed plant of the shores—especially where they are washing away. 
Taking advantage of a fine day we started at dawn for Petite Coquillage, where we 
spent the whole day examining the island, while Hancock did his best to secure us a 
representative collection of its birds. It is an oval-shaped island about 11 feet above the 
high-tide level, or 16 feet above the reef-flat, with a lower belt of loose sandy land 
applied to its western side. The higher land is bare, save for one clump mostly formed 
of papayas and a few small mapou, but its surface is covered with a close matted tangle 
several inches thick of the “liane sans feuilles” (Cassytha). It was strewn with the 
eges of grey-headed terns (Anous stolidus), at least one to every square yard, some 
SECOND SERIES.—ZOOLOGY, VOL. XII. 7 
