Before the veil of darkness was quite removed, we could faintly distinguish the mouth of the opening; and the sight at daylight was most cheering. A wide bay appearing between two white cliffy heads, and stretching away within to a great distance, presented itself to our view. Far to the southward, between the heads, rose a small table-topped hill. As we pulled in towards the eastern entrance point, the river-like appearance began to wear off, more land making its appearance towards the head of the opening. On reaching this point Mr. Forsyth and myself climbed up the cliff, whilst the breakfast was cooking. From the summit we had a good view of the bay, and were delighted to find large openings in the south-east and south-west corners of it. The table hill before mentioned, stood on the point between them. To see the eastern part of it, however, it was necessary to cross to the opposite point, where some talc slate, pieces of which measured four inches in length, was found imbedded in quartz. The point was called in consequence, Talc Head. PORT DARWIN. The other rocks near it were of a fine-grained sandstone: a new feature in the geology of this part of the continent, which afforded us an appropriate opportunity of convincing an old shipmate and friend, that he still lived in our memory; and we accordingly named this sheet of water Port Darwin. A few small bamboos grew on this head; the other trees were chiefly white gums. I climbed to the top of one of them, and obtained thence a view of another opening in the eastern part of the harbour. It now being low-water, an extensive shoal was discovered, reaching from abreast of Talc Head to the point separating the South-East and South-West openings, an extent of nearly five miles. This somewhat diminished the value of our discovery, as it limited the capabilities of the bay as a harbour. We now proceeded to explore the north-eastern and largest opening, distant six miles from our station. A large islet and a reef left the entrance only a mile wide. Expanding again, it formed two arms, one running south, the other East-South-East, between small groups of singular isolated haycock-shaped hills, about 250 feet high. Following the latter, being the largest, we found that it soon curved round, taking a southerly direction. A bank free from mangroves occurring in this bend, we availed ourselves of it, as the day was closing in, to secure some early stars for latitude and longitude. The intense pleasure afforded by traversing water that had never before been divided by any keel, in some measure compensated us for the annoyance from the mosquitoes and sandflies, that took the opportunity of assailing us while in the defenceless state of quiet necessary in making observations. Pushing out into the middle of the stream, and each wielding a beater, our tiny enemies were soon shaken off, and borne back to the shore by a refreshing North-West breeze.