The fatigue and exposure which attended our watering at this place were so great that I was obliged to give up the idea of completing it now. We had obtained, by the two trips, enough to last until the end of October, which, with the chance of finding more upon other parts of the coast, was sufficient for our intended mode of proceeding. The boats were therefore hoisted in, and preparations made to leave the anchorage. The river appears to abound with fish, particularly with mullet; and porpoises were observed as high as the first falls, a distance of fifty miles from the sea. A curious species of mud-fish (chironectes sp. Cuvier) was noticed, of amphibious nature, and something similar to what we have frequently before seen; these were, however, much larger, being about nine inches long. At low water the mud-banks near the cascade that were exposed by the falling tide were covered with these fish, sporting about, and running at each other with open mouths; but as we approached, they so instantaneously buried themselves in the soft mud that their disappearance seemed the effect of magic: upon our retiring and attentively watching the spot, these curious animals would re-appear as suddenly as they had before vanished. We fired at several, but so sudden were their motions that they generally escaped; two or three only were procured, which appeared from their lying on the mud in an inactive state to have been asleep; they are furnished with very strong pectoral and ventral fins with which and with the anal fin, when required, they make a hole, into which they drop. When sporting on the mud, the pectoral fins are used like legs, upon which they move very quickly; but nothing can exceed the instantaneous movement by which they disappear. Those that were shot were taken on board, but on account of the extreme heat of the weather they had become so putrefied as to be totally unfit for preservation. July 30. The next day, the 30th, was spent in examining some bights in the narrow part of the channel near Gap Island, so named from a remarkable division in its centre, through which the high-tide flows, and gives it the appearance of being two islands. It was on this occasion that we explored Halfway Bay, where we were fortunate in finding good anchorage, and in which we also discovered a strait, that on a subsequent examination was found to communicate with Munster Water, and to insulate the land that forms the north-west shore of the bay: this island was called after the late Right Honourable Charles Greville, whose name has also been given to a family of plants (grevillea) that bears a prominent rank in the botany of this country. The strait, in which the tide was running at the rate of six or seven knots, was not more than one hundred and fifty yards wide; but in one part it was contracted to a much narrower compass, by a bed of rocks that nearly extended across the strait, and which must originally have communicated with the opposite shore.