Narrative of the Voyage of H.M.S. Rattlesnake, Commanded By the Late Captain Owen Stanley - Volume 2 by John MacGillivray (the dot read aloud TXT) 📖

a new reef was discovered during the passage from Cape Deliverance to Sydney of H.M.S. Meander, Captain the Honourable H. Keppel. While this sheet was passing through the press, I saw an announcement of the total wreck upon Kenn Reef-one of those the position of which is uncertain-of a large merchant ship, the passengers and crew of which, 33 in number, fortunately however, succeeded in reaching Moreton Bay in their boat-a distance of 400 miles.)

PRACTICAL RESULTS OF THE SURVEY.

The most important practical result of Captain Stanley's survey of the Louisiade Archipelago and the south coast of New Guinea, was the ascertaining the existence of a clear channel of at least 30 miles in width along the southern shores of these islands, stretching east and west between Cape Deliverance and the north-east entrance to Torres Strait-a distance of about 600 miles. This space was so traversed by the two vessels of the expedition without any detached reefs being discovered, that it does not seem probable that any such exist there, with the exception of the Eastern Fields of Flinders, the position and extent of which may be regarded as determined with sufficient accuracy for the purposes of navigation, and the reefs alluded to in Volume 1, which, if they exist at all, and are not merely the Eastern Fields laid down far to the eastward of their true position, must be sought for further to the southward. The shores in question may now be approached with safety, and vessels may run along them either by day or night under the guidance of the chart-without incurring the risk of coming upon unknown reefs, such as doubtless exist in other parts of the Coral Sea further to the southward-judging from the occasional discovery of a new one by some vessel which had got out of the beaten track. Whalers will no doubt find it worth their while-with the characteristic enterprise of their class-to push into those parts of the Coral Sea now first thrown open to them, and, although we have not as yet sufficient grounds to warrant the probability of success in the fishery, yet I may mention that whales were seen on several occasions from both of our vessels.

USEFUL PRODUCTIONS OF NEW GUINEA.

This naturally originates the question-to what extent do the Louisiade Archipelago and the south-east coast of New Guinea afford a field for commercial enterprise? What description of trade can be established there by bartering European goods for the productions of these countries? Unfortunately at present most of the evidence on this point is of a negative kind. Besides articles of food, such as pigs, yams, and coconuts, and weapons and ornaments of no marketable value-tortoise-shell, flax, arrowroot, massoy bark, and feathers of the birds of paradise were seen by us, it is true, but in such small quantities as to hold out at present no inducement for traders to resort to these coasts for the purpose of procuring them. That gold exists in the western and northern portions of New Guinea has long been known, that it exists also on the south-eastern shores of that great island is equally true, as a specimen of pottery procured at Redscar Bay contained a few small laminar grains of this precious metal. The clay in which the gold is embedded was probably part of the great alluvial deposit on the banks of the rivers, the mouths of which we saw in that neighbourhood, doubtless originating in the high mountains behind, part of the Owen Stanley Range.

It is evident, however, that our acquaintance with the productions of a great extent of coastline upon which we never once landed must be very slight, but with that little we must be content until some more complete exploration of the shores, which were only cursorily examined, and especially of the rivers of the Great Bight-which seem to offer a ready means of penetrating far into the interior of New Guinea-shall have been effected. That an expedition with this end in view will soon be undertaken is, however, highly improbable, the survey of the Rattlesnake having completed all that was requisite for the immediate purposes of navigation in those parts.

GEOLOGICAL REMARKS.

The fact of the existence of several active volcanoes on islands immediately adjacent to the north coast of New Guinea (first made known by Dampier) and the circumstance of volcanic bands traversing the length of many of the great islands of the Malayan Archipelago, and others as far to the southward as New Caledonia and New Zealand, rendered it extremely probable that we should have found indisputable signs of comparatively recent volcanic action in the south-east part of New Guinea. We saw no volcanoes, however, and the great central mountain chain appeared to me to be probably granitic. The large Brumer Island is composed of igneous rocks as formerly mentioned; and at Dufaure Island I obtained from some canoes which came off to us a few smooth water-worn pieces of hornblendic porphyry. Some specimens of obsidian, or volcanic glass, were also procured from the natives at the latter place, where sharp-edged fragments are used for shaving with; one variety is black, another of a light reddish-brown, with dark streaks. Mount Astrolabe is apparently of trap formation, as I have already stated. Some conical hills scattered along the coast may possibly be of volcanic origin, especially one of that form rising to the height of 645 feet from the lowland behind Redscar Head. It is in this neighbourhood also that we find the upraised calcareous rocks of modern date exhibited by the Pariwara Islands and the neighbouring headland, with which they were probably once continuous; near this, too, the barrier reef of the coast ceases at Low Island, which it encloses, although its line is continued under water, as a ridge of coral, as far as the South-west Cape, where the coral ends, unless the shoals apparently blocking up the channel south of Yule Island are of the same formation.

LOUISIADE ARCHIPELAGO.

Reference to the outline chart will enable the reader to follow me in some general remarks which did not properly enter into the narrative. The Louisiade Archipelago, reduced to what I conceive to be its natural limits, includes that extensive group of islands comprised between the parallels of 10 degrees 40 minutes and 11 degrees 40 minutes South latitude, and the meridians of 151 degrees and 154 degrees 30 minutes East longitude. About eighty are already known, and probably many others remain yet to be discovered in the north-west, a large space there being as yet a blank upon the chart. All the islands of the group, with the exception of the low ones of coral formation to the westward, appear to be inhabited, but probably nowhere very densely, judging from the comparatively small number of natives which we saw, and the circumstance of the patches of cultivation being small and scattered, while the greater part of the large islands is either covered with dense forest, or exhibits extensive grassy tracts with lines and clumps of trees. Such of the islands as were examined consisted of mica slate, the line of direction of the beds of which is nearly the same as that of the Archipelago itself, and the physical appearance of the other islands leads me to believe that the same rock prevails there also.

CORAL REEFS OF THE LOUISIADE ARCHIPELAGO DESCRIBED.

One of the most remarkable features connected with the Louisiade Archipelago is the manner in which its shores are protected by the coral reefs which have frequently been alluded to above. The principal of these are good examples of that kind distinguished by the name of barrier reefs. Rossel Reef has already been described, and the only other large one of this description which we saw more than a portion of, is that partially encircling South-east Island at a variable distance from the land, then passing to the westward as far as longitude 152 degrees 40 minutes, where it ceases to show itself above water; thence, however, the edge of a bank of soundings (represented on the chart by a dotted line) which is suddenly met with in coming from the deep blue unfathomed water to the southward, can be traced in a continued line to the westward as far as the Jomard Isles, whence it turns round to the northward for ten miles further, where our examination ended. This last may be considered as a submarine extension of the barrier, which probably reappears again above water, and passing to the northward of the Calvados Group, reaches as far as the northern entrance to Coral Haven, enclosing nearly all the high islands of the Archipelago. The expanse of water inside when not occupied by land usually exhibits a depth of from 15 to 30 fathoms, with numerous sunken patches of coral, and several reefs which partially dry at low-water. The shores of the islands also are generally protected by fringing coral reefs, the largest of which is that extending off the west and south side of Piron Island to a distance of seven or eight miles, with a well defined border towards Coral Haven.

At the western portion of the Louisiade Archipelago the reefs seen by us exhibit great irregularity of outline, continuity, and width. Some are linear reefs, others atolls* more or less distinct in character, and the remainder are usually round or oval. Viewed as a whole they form an interrupted chain, with numerous deepwater channels, which terminates in the West Barrier Reef of the chart but is connected with the coast of New Guinea by a bank of soundings, with, probably, a well-defined margin. Many low, wooded islands are scattered along this line. I know of no distinguishing feature presented by the coral reefs of the Louisiade compared with those which I have seen elsewhere. One remarkable occurrence, however, connected with them, may be mentioned. While passing in the ship the most northern point of Rossel Island, I observed upon the reef, about a hundred yards inside its outer border, a series of enormous insulated masses of dead coral rising like rocks from the shallow water. The largest of these, examined through a good telescope from the distance of half a mile, was about twenty feet in length and twelve in height, with a well-defined high-water mark. It formed quite a miniature island, with tufts of herbage growing in the clefts of its rugged sides, and a little colony of black-naped terns perched upon the top as if incubating.

(*Footnote. "An atoll differs from an encircling barrier reef only in the absence of land within its central expanse; and a barrier reef differs from a fringing reef in being placed at a much greater distance from the land with reference to the probable inclination of its submarine foundation, and in the presence of a deep water lagoon-like space or moat within the reef." The Structure and Distribution of Coral Reefs by Charles Darwin page 146.)

THEORY OF THEIR FORMATION.

I had only once before seen a similar exhibition of such great and permanently elevated masses of dead coral upon a living reef-a phenomenon of much interest in connection with Mr. Darwin's theory of the mode of formation of coral reefs. This was on a portion of the Great Barrier Reef of Australia, visited in company with Mr. Jukes, who has published a detailed account of it.* In both cases the only obvious explanation is that these huge blocks-too massive to have been hove up from deep water into their present position by any storm-reached their present level by the elevation of the sea bottom on which they were formed.

(*Footnote. Voyage of H.M.S. Fly by J.B. Jukes volume 1 page 340.)

Before quitting the subject of the coral reefs of the Louisiade I may be permitted to express my conviction of the perfect manner in which