(*Footnote. As we shall refer all longitudes during this cruise to Scott's Jetty, Swan River, I may here state that the approximate longitude of that place is considered to be 115 degrees 47 minutes East of Greenwich.) A few remarkable clumps of mangroves pointed out the position of some lagoons about a mile and a half from the south end of the island, which is fronted by a line of low overhanging cliffs of recent, cream-coloured limestone. Upon these rests a layer of a kind of soil, in some places eighteen inches deep, in others four feet, in which the seabirds burrow, and which, from what I have since seen of the much sought after guano, I believe to contain some of the valuable substance. In some of the islands forming Houtman's Abrolhos which we subsequently examined, I found similar signs of the presence of this manure, which I think worthy of being made the subject of enquiry. On the south part of the island I found a block of scoria measuring three feet by two; which, though not appearing to possess the power of floating, must have been brought by the current from the volcanic island of St. Paul's. We saw a few hair-seals on the beach when we landed, and a rich kind of rock oyster was found at low-water. PELSART GROUP. On the south west point of the island the beams of a large vessel were discovered, and as the crew of the Zeewyk, lost in 1728, reported having seen the wreck of a ship on this part, there is little doubt that the remains were those of the Batavia, Commodore Pelsart, lost in 1627. We in consequence named our temporary anchorage Batavia Road, and the whole group Pelsart Group. It was the wreck of this Dutch ship that led to the discovery of this part of the continent of Australia, Commodore Pelsart himself having crossed over to it in a boat in search of water. VISIT TO THE MAIN. April 8. In the afternoon we got underweigh, with a fresh south wind. The low neck over which the boat was hauled, and which appeared like a gap from the offing, bearing west, led clear to the northward of the two fathom patch. We steered across East by South 1/2 South for the main, losing sight of the island from the Beagle's poop (height 15 feet) at the distance of five miles and a half. Three miles further brought us in sight of the land, forming a high level range, with a knob or lump on its south extreme. Some five or six miles to the south-east were seen isolated peaks, which we rightly supposed to be the Wizard Hills of Captain King, whilst the lump above spoken of proved to be Mount Fairfax, the level range being Moresby's Flat-topped Range. As we neared them the Menai Hills began to show themselves.