Meanwhile a minute survey was made by Lieutenants Dayman and Simpson of the inner entrance to Port Jackson, where a reef, called the Sow and Pigs (distinguished by a beacon and a light vessel) in the middle of the passage, leaves only a narrow available channel on either side. The exact boundaries of them, with the depth of water, were to be determined, especially to ascertain whether a line-of-battle ship, with her full armament, could pass into the harbour. The shoalest part of the west channel was found to have 21 feet, and of the east 24 feet at low-water (the rise and fall of tide being from 5 to 8 feet); consequently, at high-water there would be room for a three-decker to enter.* This work was in connection with a proposed dry dock** on Cockatoo Island, above Sydney, towards the expenses of which the Imperial Government were willing to contribute, provided it were made of such a size as to be available for large steamers and line-of-battle ships.
(*Footnote. It was found by comparison with Lieutenant Roe's survey, made 25 years before, that the inner edge of the shoal had extended considerably to the southward.)
(**Footnote. This has for several years been under construction; its importance will appear more evident, when it is considered that a large vessel in the Australian colonies requiring repairs, which cannot be effected by the process of heaving down, will find no suitable place nearer than Bombay.)
In compliance with a requisition from Sir Charles Fitzroy, the Governor of New South Wales, Captain Stanley, in the Bramble, paid a visit to Twofold Bay, 200 miles to the southward of Sydney, a place of rising importance as a harbour, also in connection with whaling establishments, and the extensive adjoining pastoral district of Maneroo. The bay was resurveyed, with a view to test the comparative merits of the two townships there--one founded by government, the other by private enterprise. After all, I believe, the advantages afforded by each of the rival establishments are so equally divided, that the question still remains an open one.
SAIL UPON FIRST NORTHERN CRUISE.
October 11th.
After a protracted stay in Sydney of very nearly three months, we were at length enabled to start upon our first cruise to the northward, the object of which was to make a survey of Port Curtis and part of the Inshore Passage leading up to Torres Strait. The Rattlesnake and tender got under weigh soon after daybreak and ran out of Port Jackson to the northward with a fine South-east wind. In the evening the Bramble parted company, her present destination being Port Stephens, for the purpose of running a meridian distance, and ours Moreton Bay.
One day, while off Cape Byron, an interesting addition to zoology was made in a small floating shellfish, which has since proved to constitute a new genus,* throwing light, I am informed, upon many fossil univalves in the older formations; and a rare bird of the noddy kind (Anous leucocapillus) perched on the rigging towards evening, and was added to the collection; for even the beauty and innocence of a tired wanderer like it was insufficient to save it from the scalpel.
(*Footnote. This mollusc, allied to Litiopa, Professor E. Forbes has done me the honour to publish in the Appendix as Macgillivrayia pelagica.)
ARRIVE AT MORETON BAY.