14-2 MINERALS IN CEYLON.
I have indicated their position on the map. The first is one which outcrops a few miles this side of Balangoda, and runs N.N.W., occurring again at Hanuwala.
The second runs through Dolosbage and Maskeliya; probably the bed occurring at Bilhul-oya is continuous with this.
The third outcrops under the Great Western on the Great Western estate, and is continuous to the N.N.W. with the Wattegoda and Medakumbura dolomites, and probably also with the beds at Gampola and Kurunegala. A subsidiary bed—or it may be an outlier of this—occurs near the Pussellawa rest-house.
The fourth bed outcrops largely at Wilson's Bungalow, Glen Devon, Punt-bara and Matale.
The fifth occurs in the Badulla district. As in the gneiss we have a great many varieties so also in the dolomites. They all contain carbonate of magnesia, which varies from I to over 40 p.r cent.
These limestones are very valuable for estate purposes as well as for building stone and building lime.
In colour they vary much, dependent on the numerous accidental minerals that occur along with them. Thus the specimens from Wilson's Bungalow are very' dark : they contain pyrites, phlogopite, chlorite, epidote, &c.
A dolomite occurring at Wariapola on the Matale railway contains a large amount of blue spinel. Some of the crystals of these dolomites have large facets, others small and of a granular texture. Many contain white translucent siliceous grains not easily distinguished.
A beautiful example of limestone of a somewhat peculiar tinge, due to the metal chromium, occurs beyond Balangoda, and often contains fine specimens of crystalline biotite—a magnesian mica. This limestone shews a very-peculiar and characteristic weathered surface.
Plumbago is found in several localities as at Kurunegala, Kegalla and Nambapana. In the Balangoda district we have the metal molybdenum, so useful in chemical researches; and black oxide of manganese from Ratnapura and neighbourhood.
Various forms of iron occur in the gneiss, thus iron pyrites. Magnetite, a very highly magnetic iron ore, is found in the Pussellawa district with a peculiar cleavage and fracture. Botryoidal limonite, an oxide of iron found under the cinnamon sand near Negombo. Haematite occurs in other parts of the island.
Traces of gold and platinum I have met with in the Ramboda and Kurunegala districts. Extensive beds of quartz occur in the Pussellawa district, which is not much unlike the reef-bearing quartz of the Wynaad.
In some localities the felspar of the gneiss is much decomposed and forms large masses of kaolin (Kirimeti of the Sinhalese), occurring largely in the Nuwara Eliya and Maturata districts. This is capable of being made into a very fair porcelain.
Large masses of alluvium occur on the Nuwara Eliya plain, and shew us the remains of. the surrounding hills, deposited no doubt in a former lake.
In the alluvium of many of our river basins, notably at Ratnapura, we have numerous minerals—the gems for which this town is so noted. I will briefly notice some which I have gathered there.
First, I will deal with the corundum or sapphire family, which crystallizes in the hexagonal system. If a stone of this family lacks transparency and is dull, we call it corundum : it is useful as a powder (emery) for cutting other stones. If of a rich blue colour it is called sapphire; of white, white sapphire; red, ruby: purple, the oriental aniethyst: of yellow, the oriental topaz; of green, the oriental emerald.
Some of the sapphires are partly blue and partly white. The Sinhalese can, by heating these in a certain manner, distribute the colour evenly, or by greater heat can discharge the colour and so pass them off as white sapphires. The specific gravity of such, however, is diminished, Many other
