formed, _like most_ of the shoals hereabouts, of a belt of coral-rocks, “with a basin of deep water within.”—_Half-Moon Shoal_ has a similar structure; Captain D. Ross describes it, as a narrow belt of coral-rock, with a basin of deep water in the centre,” and deep sea close outside.—_Bombay Shoal_ appears (Horsburgh, vol. ii, p. 432) “to be a basin of smooth water surrounded by breakers.” These three shoals I have coloured blue.—The _Paraquas Shoals_ are of a circular form, with deep gaps running through them; not coloured.—A bank gradually shoaling to the depth of thirty fathoms, extends to a distance of about twenty miles from the northern part of _Borneo_, and to thirty miles from the northern part of _Palawan._ Near the land this bank appears tolerably free from danger, but a little further out it is thickly studded with coral-shoals, which do not generally rise quite to the surface; some of them are very steep-to, and others have a fringe of shoal-water round them. I should have thought that these shoals had level surfaces, had it not been for the statement made by Horsburgh “that most of the shoals hereabouts are formed of a belt of coral.” But, perhaps that expression was more particularly applied to the shoals further in the offing. If these reefs of coral have a lagoon-like structure, they should have been coloured blue, and they would have formed an imperfect barrier in front of Palawan and the northern part of Borneo. But, as the water is not very deep, these reefs may have grown up from inequalities on the bank: I have not coloured them.—The coast of _China, Tonquin_, and _Cochin-China_, forming the western boundary of the China Sea, appear to be without reefs: with regard to the two last-mentioned coasts, I speak after examining the charts on a large scale in the “Atlas of the Voyage of the _ Favourite_.”