ON THE BLACK LIMESTONE AT 

 KAMUNING. 



On tlie road hetweeu Enggor (on tlie Pei'alc River) and 

 Ipoli, and at about nine miles from the form(>r place, is a 

 pictTires(]ue limestone hill called Changkat Kamnning. It is 

 perhaps some 600 to 800 feet in height, and is composed of a 

 l)lack limestone differing in niauy respects from that of a similar 

 colour found in other parts of the State. 



The limestone is nearly black in colour, with occasional 

 veins of pure white. It is soft and is easily cut with a knife, 

 yields a grey powder, aud has an uneven fracture, dl^ll in the 

 direction of the grain and minutely sparkling across the grain. 

 It blackens the hands when handled, and when rubbed with a 

 hard substance pi'esents a polished black surface. In thin 

 sections under the microscope it is seen to be made up of white 

 crystalline carbonate of lime, enclosing opaque black shining 

 scales and irregular masses. When a fragment is put into dilute 

 acid the lime dissolves, leaving a black powder, which under the 

 microscope presents the appeai'ance, in miniature, of pieces of 

 coke. The grains are of different sizes and very diverse shapes. 

 The powder is slightly gritty between the fingers, from admix- 

 ture of a small amoimt of quartz sand. The particles of this 

 substance, by their appearance, suggest the idea that they have 

 been in a plastic state and that the crystallization of the en- 

 closing calcite gave them their present form. This is best 

 shown in a decalcified section of the rock. 



The l")lack powder when rubbed on paper, or lietween the 

 fingers, presents the characteristic appearance of ])lumbago, wliile 

 before the blowpipe it l>eliaves in the same way as that substance, 

 and if heated with nitre it deflagrates. It is therefore carbon 

 in the form of graphite. 



