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.