MINERALOGICAL DESCRIPTION’ OE THE ISLAND OF BANKA. 407 
latter in a state of decomposition. In some specimens the crystals 
of quartz are very minute, and these resemble a white sand-stone, 
7. An aggregate stone consisting of very minute, or of larger 
fragments of quartz, united to an amygdaloid by a gluten of ochres 
of various colours, from light yellow to dark red: it occurs in lami¬ 
nae of various forms and a great variety in the admixture of compo¬ 
nent parts, in some instances minute particles of tin-ore are closely 
adhering to the fragments. 
8. Argillaceous Iron-ore, of dark brown colour, particles of quartz 
closely adhering to the surface, which in many parts are covered with 
yellow ochre. 
9. Almost pure clay of a grey colour in masses. 
10. Large masses of a white substance which is considered by 
the Chinese miners as an unequivocal indication of the termination 
of a stratum of ore, the name is Kongtay. It is of the purest white 
colour, very light and adheres strongly to the tongue, it possesses all 
the proporties of pure clay; and the manner in which it is found, de¬ 
monstrates plainly that it is a deposition from water. On this the 
ore of tin is composed in strata differing in richness and extent and 
mixed with the various kinds of stone which are from time to time 
enumerated in the account of the mines. 
The mines of Sungei Tango, as well as those of Sungei Bul&k 
above mentioned, have been worked for many successive years, and 
their neighbourhood forms the most extensive, naked tracts of the 
country in this part of the Island, 
Proceeding from here to Kldbbet the road leads almost in a west¬ 
ern direction through a most luxuriant forest, the soil of which 
consists of a thick black vegetable mould. 
The most important mine in this district is that of Sinhin , it em¬ 
ploys 32 workmen and is the second in productiveness of those at 
present worked in Banka. I found the miners within 6 feet of the 
stratum of ore : they were engaged in carrying out the earth from an 
extensive pit of an oblong form. 
On one of the sides I remarked the following succession of strata : 
1. Vegetable mould. 
