

88 Mineralogical Description of the Island of Banka. 



process of mining has greatly contributed to illustrate their com- 

 position ; and it is one chief object in the following details to give 

 a clear account of the component parts of the strata, in as far as 

 these were illustrated by the various fragments of stone found at 

 the aqueducts of the mines. 



8. Forming part of these strata and distributed through the 



more solid parts, are extensive masses of clay of various colors, 

 from pure white to yellow and red ; a black earthy substance 

 which, for the sake of distinction, I have called black clay, occurs 

 in irregular masses (with few exceptions) in every mine ; and the 

 termination of a stratum is indicated by a peculiar white clayey 

 substance which becomes friable by drying and is called Kong- 

 tay by the Chinese. 



I have proposed in the mineralogical remarks, to follow the or- 

 der in which they were made during a tour through part of the 

 Island of Banka, without any respect to regularity or relative 

 importance ; dating the commencement of my investigations 

 from my arrival at Kampak, in March, after a passage of two days 

 from the settlement of Rangam. In my course around the west- 

 ern extremity of Banka, during which the vessel remained near 

 the shore, I had a good opportunity of observing the direction 

 and extent of the mountain Manumbing and its western and east- 

 ern appendages, with part of that range which extends from it, 

 to the eastward. 



That tract of country which lines the Bay of Jebus between 

 the hills of Pari-pari on the north, and of Manumbing and its 

 appendages on the south, must be considered as one of the allu- 

 vial districts of Banka; besides several others of less note, the 

 rivers o£ Sungeibulo, Kampak, Palungasand Rambat pass through 

 it. In proceeding up the river of Kampak, I remarked numerous 

 rocks projecting beyond the surface. 



I examined them at a cluster which forms a small island called 

 by the natives Batu-lu/cut, about one hundred yards in circum- 

 ference. The external form of the entire rocks is rather rounded 

 than sharp; the highest project, at the present season, about ten 

 feet beyond the level of the river. The external color of the 

 rock is of a dirty hue ; the surface is very unequal and rough, 

 excavated by fissures, crossing each other in various directions, 

 into irregular angles and rhombs, &c, or marked in a similar 

 manner by white streaks or veins. The fracture is intensely 

 white, some portions appearing glistening as pure quartz, others 

 dull and chalky. 



When struck with a hammer, it separates at the fissures, which 

 appear on the surface, into irregular fragments. It also frequently 

 follows the direction of the streaks or lines: these are formed of 

 quartz, and are semi-transparent, frequently approaching the nature 

 of rock-crystal. They often separate from the common mass of the 



