the direction of the island being from north-west to south-east, it follows, not only the direction of Sumatra and the Malayan peninsula, but also the great chain of Asiatic mountains, one of the many branches of which terminates in Ceylon, while another, traversing Arakan, Pegu, the Malayan peninsula, and probably Sumatra, sends off an inferior range through Banca and Billiton, where it may be considered to disappear.
The elevated parts of Banca are observed to have the same constitution as the great continental chain, being composed principally of granite; after which occurs a species of rock which Dr. Horsefield terms red iron-stone, extensively distributed in situations of secondary elevation, in single rocks, or in veins covering large tracts of country. Tracts composed of this rock are bounded by alluvial districts, which are again subdivided into undulating hills, gradually rising on others of apparently prior formation, and such as are low and level, of recent origin, and bordering on the mouths of the rivers. Those districts which, occurring in juxta-position with the primitive portions, fill that space between these latter and the veins of red iron-stone, or, again, between those and the alluvial parts, are stratified; and the strata uniformly horizontally arranged.
It is through these horizontal strata that the tin-ore is represented to be disseminated; and, as far as has hitherto been remarked, it appears to be either immediately under the surface, or at no great distance from it.
Another section of the report contains a view of the tin-mines, exhibiting a general enumeration of those worked at present, or in former periods; with an account of the process of mining, and the economy of the mines.
The process of mining in Banca is remarkable for its simplicity. It consists in an excavation, of a square or oblong form, made by digging perpendicularly to the beds or strata containing the ore, and in a proper application of the water to facilitate the labors of the miners, and the washing of the ore. There is no necessity in Banca, as in countries where the metal lies concealed in deep veins, to have recourse to difficult operations, or expensive machinery; and the process, indeed, requires so little previous instruction, that it is mostly performed by persons whose only qualification is a robust constitution. A favorable spot being selected, the pit is sketched out, a canal conducted from the nearest rivulet, and then, the miners excavate the soil until they arrive at the stratum containing the ore, which is next deposited in heaps near the water, so as to be placed conveniently for washing: the aqueduct is lined with the bark of large trees, and, a stronger current being produced by the admission of more water, the heaps are thrown in, and agitated by the workmen; the particles of the ore subsiding through their
