These islets, which are raised only from 10 to 12 feet above the level of the sea, are a mere mass of coral and shells with a very small variety of plants struggling to establish themselves upon some of them. I was rather surprised to find a few plants of the common groundsel on one of the barest. It is not improbable that these islets are upon the outer rim of the crater of a volcano, and that not only the entire outer rim, but also a large space, both interior and exterior, will eventually be elevated. Nothing can exceed the beauty of the different sorts of coral as seen under the clear smooth water. We broke of many specimens of the branch- or tree-coral, which seemed to be in full vigour of life and activity. These islets appear to be a favourite resort of seals, many of which we saw, but of the sort called hair-seals. The sailors knocked many of them upon the head with clubs as they lay sleeping on the shores. One of these afforded much sport, though rather of a barbarous sort if one had taken time to think at all on the subject. Sleeping on the brink of a small lagoon in the interior of one of these islands, he was roused by the approaching footsteps of his enemy. Seeing the man close to him, with upraised club over his head, he dropped into the water. This was so shallow as not to protect him from the stones that were hurled at him from all sides, and so small that he was completely surrounded. Finding his retreat cut off he boldly stood up and seemed deliberately to scan the most practicable mode of breaking his way through us all, but he was so incessantly plied with stones as entirely to distract him. When a well-aimed blow struck him he wreaked his vengeance on the stone, and, diving after it to the bottom, gnashed upon it with his teeth. At last a gun was brought by one of the party and a well-directed shot under the ear laid him dead. Rock oysters of a large size and delicious flavour were found in great abundance. Range of thermometer 67 to 82 degrees. On Sunday the 12th continued to explore the several islands; unable to land upon the first we approached on account of a reef which ran all round it. This was one which lay at the north-east extremity of the Horseshoe. It was high and sandy, but with some vegetation on the surface, and we saw many large seals sleeping on the sandy beach. After this, visited five or six in succession, all of the same formation, some being mere masses of loose coral and dead shells. SINGULAR CORAL FORMATIONS.