XIX.] 
THE COAL-SEAMS OF LABUAN. 
407 
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, notwith¬ 
standing 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 formly 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 palseontology. 
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 ex¬ 
ceedingly 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 
