possessing the characters of the muds which were found by the “Challenger” Expedition to be at present forming around oceanic volcanic islands in depths probably of from 150 to 500 fathoms. Coral limestones encrust the lower slopes of these islands and do not attain a greater thickness than 150 feet. The next type is to be found in Treasury Island which has a similar structure to that of Ugi, but possesses in its centre an ancient volcanic peak that was once submerged and is now covered over by these recent deposits. Then, there are islands, such as the principal island of the Shortlands, in which the volcanic mass has become an eccentric nucleus, from which line after line of barrier-reef has been advanced based on the soft deposits. These soft deposits contain amongst other organic remains, the shells of pteropods and the tests of foraminifera in great abundance. In such islands I did not find that the coral limestone had a thickness of as much as 100 feet. In this island the upraised reefs are based upon hard foraminiferal limestones. Lastly, we have the upraised atoll of Santa Anna which within the small compass of a height of 470 feet displays the several stages of its growth; first, the originally submerged volcanic peak; then, the investing soft deposit resembling in character a deep-sea clay and considered to have been formed in considerable depths, probably from 1500 to 2000 fathoms; and over all, the ring of coral limestone that cannot far exceed 150 feet in thickness. The islands formed mainly of the soft foraminiferous deposits have long level summits free from peaks. Judging from their profiles, the islands of Ulaua and Ronongo will be found to possess the structure of Ugi and Treasury. The western end of Choiseul has a very significant profile, and I have little doubt from my examination of the lower slopes that this extremity of the island is mainly composed of the recent soft deposits.

I now proceed to refer very shortly to the coral reefs[3] of these islands. The three principal classes are to be found in this region; but of these, the fringing and barrier-reefs are more commonly distributed, whilst the atolls are comparatively few in number and of small size. A line of barrier-reefs, probably not much under 60 miles in length and bearing innumerable islets on its surface, fronts the east coasts of the islands of New Georgia at a distance of from one to three miles from the shore. Extensive reefs of the same class, having a broad deep-water channel inside them, lie off the large island of Isabel and off the south-coast of Choiseul. Barrier-reefs, of smaller extent, also skirt the west end of Guadalcanar and the southern end of Bougainville. I have referred particularly to these reefs because at the time that Mr. Darwin wrote his work on “Coral Reefs,” fringing-reefs were alone believed to exist in these islands.

The larger islands of the Solomon Group are often separated from each other by depths of several hundred fathoms. St. Christoval, for instance, is separated from the neighbouring islands of Guadalcanar and Malaita by straits in which casts of 200 fathoms fail to reach the bottom. On the other hand, the same 100 fathom line includes both Bougainville and Choiseul. Judging, however, from the soundings obtained by Lieut.-Commander Oldham between the islands lying off the north coast of St. Christoval, it would appear probable that depths of 400 fathoms commonly occur between the islands of the Solomon Group. Although the soundings hitherto made in this portion of the Western Pacific go to show that this archipelago, together with New Ireland and New Britain, are included within the same 1,000 fathom line, which extends as a loop from the adjacent borders of New Guinea, we can scarcely urge this fact as evidence of a former land connection, seeing that one of the most interesting features in the geological history of this region is that of the enormous elevation which these islands have experienced in recent and probably sub-recent times. Independently of the character of the deposits discovered by me in the Solomon Islands, I arrived at the conclusion that there had been a recent upheaval of at least 1,500 feet. The characters of some of the deposits, as examined by Dr. Murray in the light of the “Challenger” soundings, however, afford indications of an upheaval of a far more extensive nature. I am informed, in fact, by Mr. H. B. Brady, that the foraminifera of some of the Treasury Island rocks indicate depths of probably from 1500 to 2000 fathoms. Geologists may look forward with the greatest interest to the results of the examination by Mr. Brady of the foraminiferous deposits of the Western Pacific. One of the most important results will be to establish the great elevation which has occurred in this region during Post-Tertiary times. We are therefore justified in regarding the island groups of the Western Pacific as having always retained their insular condition, situated, as they are, in a region of upheaval, and separated, as they are, from each other and from the Australian continent by depths of from 1,000 to 2,400 fathoms. I have already pointed out that the volcanic rocks of the large islands of the Solomon Group are geologically ancient. Their elevation and the great subaerial denudation which they have experienced afford indications of the insular condition having been preserved from remote ages. It is this prolonged isolation that explains the occurrence of the peculiar forms of the amphibia which I discovered in Bougainville Straits, and that accounts for many of the peculiarities of the fauna of this archipelago.

Having thus briefly considered the leading geological and hydrological features of this group, I pass on to consider these islands in the point of view of an intending settler. They are for the most part clothed with dense forest and rank undergrowth, and it is only here and there, as in the western portion of Guadalcanar and in limited localities in St. Christoval, that the forest gives place to long grass and ferns, a change often corresponding with the passage from a clayey and calcareous to a dry porous and volcanic soil. As a rule, the calcareous districts of a large island possess a rich red argillaceous soil, often 5 or 6 feet in thickness, and in such localities the streams are large and numerous. In the districts of volcanic formation the soil is dry, friable, and porous, whilst the streams are few in number and of no great size. In the principal island of the Shortlands the difference in the character of the soil between the volcanic north-west part and the remaining calcareous portion is well exhibited. In the smaller islands the soil varies in character according to the formation, those of volcanic origin being singularly destitute of streams.

In chapter XVII. I have dwelt with some detail on the climate. The healthiest portion of the group would, as I think, be found in the eastern islands, and the healthiest part of each island would be