COOK or HARVEY and AUSTRAL ISLAND.—_Palmerston_ Island is minutely described as an atoll by Captain Cook during his voyage in 1774; coloured blue. _Aitutaki_ was partially surveyed by the “Beagle” (see map accompanying “Voyages of ‘Adventure’ and ‘Beagle’”); the land is hilly, sloping gently to the beach; the highest point is 360 feet; on the southern side the reef projects five miles from the land: off this point the “Beagle” found no bottom with 270 fathoms: the reef is surmounted by many low coral-islets. Although within the reef the water is exceedingly shallow, not being more than a few feet deep, as I am informed by the Rev. J. Williams, nevertheless, from the great extension of this reef into a profoundly deep ocean, this island probably belongs, on the principle lately adverted to, to the barrier class, and I have coloured it pale blue; although with much hesitation.—_Manouai_ or _Harvey_ Island. The highest point is about fifty feet: the Rev. J. Williams informs me that the reef here, although it lies far from the shore, is less distant than at Aitutaki, but the water within the reef is rather deeper: I have also coloured this pale blue with many doubts.—Round _Mitiaro_ Island, as I am informed by Mr. Williams, the reef is attached to the shore; coloured red. —_Mauki_ or Maouti; the reef round this island (under the name of Parry Island, in the “Voyage of H.M.S. ‘Blonde’,” page 209) is described as a coral-flat, only fifty yards wide, and two feet under water. This statement has been corroborated by Mr. Williams, who calls the reef attached; coloured red.—_Aitu_, or Wateeo; a moderately elevated hilly island, like the others of this group. The reef is described in Cook’s “Voyage,” as attached to the shore, and about one hundred yards wide; coloured red.—_Fenoua-iti;_ Cook describes this island as very low, not more than six or seven feet high (volume i., book ii., chapter iii, 1777); in the chart published in the “‘Coquille’s’ Atlas,” a reef is engraved close to the shore: this island is not mentioned in the list given by Mr. Williams (page 16) in the “Narrative of Missionary Enterprise;” nature doubtful. As it is so near Atiu, it has been unavoidably coloured red.— _Rarotonga;_ Mr. Williams informs me that it is a lofty basaltic island with an attached reef; coloured red.—There are three islands, _Rourouti_, _Roxburgh_, and _Hull_, of which I have not been able to obtain any account, and have left them uncoloured. Hull Island, in the French chart, is written with small letters as being low.—_Mangaia;_ height about three hundred feet; “the surrounding reef joins the shore” (Williams, “Narrative,” page 18); coloured red.—_Rimetara;_ Mr. Williams informs me that the reef is rather close to the shore; but, from information given me by Mr. Ellis, the reef does not appear to be quite so closely attached to it as in the foregoing cases: the island is about three hundred feet high (“Naut. Mag.” 1839, page 738); coloured red.—_Rurutu;_ Mr.