The two latter are of the finest
quality and in immense abundance. The rocks of Ceylon are
primitive, consisting of granite, gneiss and quartz. Of these
the two latter predominate. Dolomite also exists in large
quantities up to an elevation of five thousand feet, but not
beyond this height.
Plumbago is disseminated throughout the whole of both soil and
rocks in Ceylon, and may be seen covering the surface in the
drains by the road side, after a recent shower.
It is principally found at Ratnapoora and at Belligam, in large,
detached kidney-shaped masses, from four to twenty feet below the
surface. The cost of digging and the transport are the only
expenses attending it, as the supply is inexhaustible. Its
component parts are nineteen of carbon and one of iron.
It exists in such quantities, in the gneiss rocks that upon their
decomposition it is seen in bright specks like silver throughout.
This gneiss rock, when in a peculiar stage of decomposition, has
the appearance and consistency of yellow brick, speckled with
plumbago. It exists in this state in immense masses, and forms a
valuable buildingstone, as it can be cut with ease to any shape
required, and, though soft when dug, it hardens by exposure to
the air. It has also the valuable property of withstanding the
greatest heat; and for furnace building it is superior to the
best Stourbridge fire-bricks.
