The coal mine is sunk on coal-seams, which come to the surface on the north side of the island. The seams, according to the information I received on the spot, are four in number, with a thickness of 3.3, 0.9, 0.4 and 1.0 metre. They dip at an angle of 30° towards the horizon, and are separated from each other by strata of clay and hard sandstone, which together have a thickness of about fifty metres. Above the uppermost coal-seam there are besides very thick strata of black clay-slate, white hard sandstone with bands of clay, loose sandstone, sandstone mixed with coal, and finally considerable layers of clay-slate and sandstone, which contain fossil marine crustacea, resembling those of the present time. The strata which lie between or in the immediate neighbourhood of the coal seams do not contain any other fossils than those vegetable remains, which are to be described farther on. Thirty kilometres south of the mine a nearly vertical coal-seam comes to the surface near the harbour, probably belonging to a much older period than that referred to above; and out in the sea, eighteen kilometres from the shore north of the harbour, petroleum rises from the sea-bottom. The manager of the mine supposed from this that the coal-seams came to the surface again at this place. The coal-seams of Labuan are besides, notwithstanding their position in the middle of an enormous, circular, volcanic chain, remarkably free from faults, which shows that the region, during the immense time which has elapsed since these strata have been deposited, has been protected from earthquakes. Even now, according to Wallace, earthquakes are scarcely known in this part of Borneo.
From what has been stated above we may conclude that the coal, sand, and clay strata were deposited in a valley-depression occupied by luxuriant marshy grounds, cut off from the sea, in the extensive land which formerly occupied considerable spaces of the sea between the Australian Islands and the continent of Asia. A similar state of things must besides have prevailed over a considerable portion of Borneo. On that island there are coal-seams under approximately similar circumstances to those on Labuan. So far as I know, however, they have not hitherto been closely examined with respect to vegetable palæontology.
At Labuan fossil plants are found, though very sparingly, imbedded in balls of clay ironstone from strata above the two lowermost coal-seams. The upper coal-seams are besides exceedingly rich in resin, which crosses the coal in large veins. From the thickness and conversion into a hard sandstone of the layers of sand lying between and above the coal-seams we may conclude that a very long time, probably hundreds of thousands or millions of years have passed since these coal-seams were formed. They also belong to a quite recent period, during which the vegetation in these regions varied perhaps only to a slight extent from that of the present time. It is, however, too early to express one's self on this subject, before the fossils which we brought home have been examined by Dr. Nathorst.
Coal mining was stopped for the time, but orders were expected by every post to resume work. The road between the mine and the harbour town was at all events pretty well kept, and Mr. COOKE, one of the directors of the company, still lived at the place. He showed me all possible hospitality during the time I remained on the north side of the island for the purpose of collecting fossils. The rest of the time I was the guest of the acting Governor, Mr. TREACHER, a young and amiable man, who showed me several collections in natural history from Labuan and the neighbouring parts of Borneo, and after our return to Europe sent me a collection of leaves and fruit of the kinds of trees which now grow on the island. I expect that this collection will be very instructive in the study of the fossil plants we brought home with us.
At the steep shore banks on the north coast very fine sections of the sandstone strata, which lie under and above the coal, are visible. While I went along the shore in order to examine these, I visited some Malay huts built on poles. They were surrounded at flood tide by water, at ebb by the dry beach, bare of all vegetation. In order to get inside these huts one must climb a ladder two to two and a half metres high, standing towards the sea. The houses have the same appearance as a warehouse by the seaside at home, and are built very slightly. The floor consisted of a few rattling bamboo splints lying loose, and so thin that I feared they would give way when I stepped upon them. The household articles consisted only of some mats and a pair of cooking vessels. I saw no fireplace; probably fire was lighted on the beach. I could see no reason why this place should be chosen as a dwelling in preference to the neighbouring shore with its luxuriant vegetation, which at the same time was not at all swampy, unless it was for the coolness which arises from the any situation on the beach, and the protection which the poles give from the thousands of crawling animals which swarm in the grassy meadows of tropical regions. It is probable also that the mosquitos are less troublesome along the sea-shore than farther into the interior of the country.
Some of my companions saw similar huts during an excursion, which they undertook in the steam launch, to the mouth of a large river debouching on the neighbouring coast of Borneo. Regarding this exclusion Dr. Stuxberg gives the following report:
"On the 19th November Palander, Bove, and I, together with two men, undertook an excursion in the steam launch of the Vega to the river Kalias debouching right opposite to Labuan. We started at dawn, a little after six o'clock. The course was shaped first north of Pappan Island, then between the many shoals that lie between it and the considerably larger Daat Island, and finally south of the latter island.
"Pappan Island is a small beautiful island, clothed down to high-water mark with a dark green primeval forest. On Daat Island, on the contrary, the primeval forest on the east side has been cut down, and has given place to a new plantation of cocoa-nut trees, the work of a former physician on Labuan, which yields its present owner a considerable revenue.
"We had no little difficulty in finding a way over the sandy bar, which is deposited in front of the river mouth at a distance of a nautical mile and a half to three miles from the coast of Borneo. After several attempts in the course of an hour we at last succeeded in finding the deep channel which leads to the river. It runs close to the mainland on the north side, from Kalias Point to the river mouth proper. At the bar the depth was only a metre, in the deep channel, it varied between 3.5 and 7 metres, in the river mouth it was fourteen to eighteen metres and sometimes more.
"On the south side of the tongue of land, which projects north of the mouth of the Kalias, were found two Malay villages, whose inhabitants appeared to view our passage up the river with curious glances. A crowd of half or wholly naked children began a race along the shore, as soon as they set eyes upon the fast steam launch, probably in order to keep us in sight as long as possible. We now had deep water and steamed up the river without delay. The longed-for visit to some of the Malay villages we thus reserved till our return.