Du Lise Island is of a very irregular shape, both as to its surface and outline, and measures about a quarter of a mile across in various directions. It seems to be formed entirely of coral sandstone, conglomerate, and breccia, and presents to the sea on its north-west side low jagged cliffs of consolidated coral breccia, and on the opposite side a sloping beach composed of hard coral sandstone arranged in gently inclined slabs; while its surface is in one place raised into a large mound about thirty feet in height, covered with trees and rank grass, and probably composed of blown coral sand. Among the tufts of grass on the sloping sides of this mound were great numbers of Spirula-shells in a tolerably perfect condition. Many of them lay in sheltered places where they could hardly have been deposited by the agency of the wind alone, and yet if they had been dropped by birds after the latter had devoured the soft body of the mollusc, one would expect to have found the fragile shells in a more or less mutilated state, which was not the case. The circumstance is, therefore, a rather puzzling one to account for satisfactorily.
The flora was more abundant in species than at any of the coral islands to the northward. There were, moreover, no signs of the island having been inhabited; and consequently we saw no palms, for the cocoa-nut does not seem to be indigenous at any of the islands recently visited. The prevailing tree was a good-sized banyan, of which many examples appeared to be very old. There were also several Hibiscus trees. As to bushes, there were a few isolated examples of the "Veloutier blanc," while the low central part of the island, into which the sea-water penetrated so as to form a filthy salt-marsh, was covered with a dense impenetrable thicket of "Bois d'Aimanthe." Herbaceous plants were numerous, and comprised species of the families Solanaceæ, Malvaceæ, Euphorbiaceæ, and Graminaceæ.
The fauna, which was not extensive, included a brown rat, which was to be seen climbing along the upper branches of the trees, apparently in search of small birds or their eggs; a lizard; a large brown dove, pronounced by Mr. Bowdler Sharpe to be a new species of Turtur; a Zosterops, and a sun-bird, a large crab of the genus Birgus; terrestrial hermit-crabs, and many spiders.
We did not find any fresh water. The soil on the upper parts of the island was a dark loam; and although sea-birds in the shape of gannets and frigate-birds were abundant and bred on the island, I saw very little guano.
I spent the forenoon of the following day in examining the broad fringing reef, a great extent of which was laid bare by the low-water spring-tide. It was composed of coral sandstone and coral breccia, and presented a rather sterile appearance, being entirely devoid of living corals, and containing very few zoophytes in its rock pools. I was, however, interested at finding on the surface of this reef a few isolated rounded stones which were quite foreign to the surrounding formation, and whose source remains a mystery difficult of solution. One was an oblong block of hard black basalt, about a foot long, by four inches in width, while the other was a lump of clear quartz the size of an orange, and much worn by attrition. Darwin, in his "Journal of a Naturalist," mentions a similar occurrence at the Keeling Islands; and in endeavouring to account for it, inclines to the belief that such stones have been transported by floating trees, in whose roots they were originally entangled, and from whence they have become detached after the stranding of the dead tree.
From the rock-pools we picked up some large Cone-shells, as well as a few Murices, Littorinas, and Turbos. We also saw some Ophiurids, and one Holothurian.
We got under way again on the 5th of May, and, after spending several hours in taking soundings, came to an anchor in eleven fathoms, about two miles to the northward of Glorioso Island. This is the largest island of the three which constitute the Glorioso Group (Vert Island is very small indeed), and is somewhat squarish in shape, measuring a mile and a half each way. It consists of a central depressed plateau, in which the wells yield only brackish water, enclosed by two lines of circumvallation, which are composed of sand hills forming continuous ridges, and ranging from thirty to forty feet in height above the level of the sea. The outer of these two ridges is about forty yards from high-water mark on the beach, and is separated from the inner ridge by a broad and deep furrow, which sustains a luxuriant growth of "Veloutier" and "Bois d'Aimanthe" bushes. Near the centre of the island we saw the muddy bed of a marsh, now dry, which one of the negroes informed me was at certain times of the year full of salt water.
Glorioso Island is the property of a Frenchman named Carltot, who, at the time of our visit, was away somewhere in Madagascar. The population consisted of the manager—an old Frenchman—one other white man, and fifteen negro labourers; who, with their wives and families, amounted in all to twenty-seven. They were endeavouring to cultivate cocoa-nuts, but so far as we could judge, without much success; for the number of these trees bearing fruit scarcely amounted to twenty. The poor people were in great distress for want of clothes and provisions, not having seen any vessel for ten months before our arrival. They had latterly been subsisting wholly on turtle and fish, without vegetables, meal, or bread of any kind. The island was so infested with rats that it was found almost impossible to raise any vegetables. In fact, commercially, it has proved a failure, so that the wretched inhabitants were only awaiting the first opportunity for quitting it and returning to Mahé.
The flora resembled that of Du Lise. The banyan tree, called "Fouce" by the Creoles, was conspicuous, and in many instances seemed to be of great antiquity. I noticed the same land-birds as at Du Lise, but there was an addition in the occurrence of the Madagascar crow. Frigate-birds were numerous all over the island, and, strange to say, were frequently to be seen perching on the branches of tall forest trees. In using the word "forest" for the first time whilst speaking of these islands, I should add that a great portion of Glorioso was covered with a dense growth of virgin forest, upon which the clearing operations of the colonists had made comparatively feeble inroads. I need scarcely add that our proximity to the great island of Madagascar was rendered apparent by the above-mentioned novelties as to fauna and flora which we encountered on our voyage southward.
The greater portion of the circumference of the island is fringed by a broad reef of dead coral and coral sandstone, on which rests in many places a thin coating of mud or sand. This platform of reef, and also the sandy beach proper, together exhibited examples of a good many shells, most of which, however, were dead specimens. We saw representatives of the genera Conus, Turbinella, Fusus, Cypræa, Trivia, Nassa, Natica, Neritina, Haliotis, Dolium, and Oliva. Besides these shells there was little else to be seen, except fragments of organ-pipe coral (Tubipora musica), and the bleached tests of an Echinus, a species of Hemiaster (?).