latter lie to the N.E. of the Hebrides. But in none of these cases, have I met with any detailed account of their shores, or seen plans on a large scale; and it will be evident, that a fringing-reef of only thirty or even a few hundred yards in width, is of so little importance to navigation, that it will seldom be noticed, excepting by chance; and hence I do not doubt that several of these islands, now left uncoloured, ought to be red. SANTA-CRUZ GROUP.—_Vanikoro_ (Figure 1, Plate I.) offers a striking example of a barrier-reef: it was first described by the Chevalier Dillon, in his voyage, and was surveyed in the “Astrolabe”; coloured pale blue.—_Tikopia_ and _Fataka_ Islands appear, from the descriptions of Dillon and D’Urville, to have no reefs; _Anouda_ is a low, flat island, surrounded by cliffs (“‘Astrolabe’ Hydrog.” and Krusenstern, “Mem.” volume ii., page 432); these are uncoloured. _Toupoua_ (_Otooboa_ of Dillon) is stated by Captain Tromelin (“Annales Marit.” 1829, page 289) to be almost entirely included in a reef, lying at the distance of two miles from the shore. There is a space of three miles without any reef, which, although indented with bays, offers no anchorage from the extreme depth of the water close to the shore: Captain Dillon also speaks of the reefs fronting this island; coloured blue.— _Santa-Cruz_. I have carefully examined the works of Carteret, D’Entrecasteaux, Wilson, and Tromelin, and I cannot discover any mention of reefs on its shores; left uncoloured.—_Tinakoro_ is a constantly active volcano without reefs.—_Mendana Isles_ (mentioned by Dillon under the name of _Mammee_, etc.); said by Krusenstern to be low, and intertwined with reefs. I do not believe they include a lagoon; I have left them uncoloured.—_Duff’s_ Islands compose a small group directed in a N.W. and S.E. band; they are described by Wilson (page 296, “Miss. Voy.” 4to edition), as formed by bold-peaked land, with the islands surrounded by coral-reefs, extending about half a mile from the shore; at a distance of a mile from the reefs he found only seven fathoms. As I have no reason for supposing there is deep water within these reefs, I have coloured them red. _Kennedy_ Island, N.E. of Duff’s. I have been unable to find any account of it. NEW CALEDONIA.—The great barrier-reefs on the shores of this island have already been described (Figure 5, Plate II.). They have been visited by Labillardière, Cook, and the northern point by D’Urville; this latter part so closely resembles an atoll that I have coloured it dark blue. The _Loyalty_ group is situated eastward of this island; from the chart and description given in the “Voyage of the ‘Astrolabe’,” they do not appear to have any reefs; north of this group, there are some extensive low reefs (called _Astrolabe_ and _Beaupré_,) which do not seem to be atoll-formed; these are left uncoloured.