BLACK LIMESTONE AT KAMUNING. 29 



The rock has a specific gravity of 2-66 at 84° V., and 

 consists of — 



Carbonate of Lime ... ... ... 9 14 



Carbon (grapliite) ... ... ... 8'1 



Silica ... ... ... ... ... '5 



100-0 



Including the carbon in combination with the lime, there is 

 nearly 20 per cent of that substance in the rock. 



When dry, the stone is a fairly good conductor of electricity, 

 and if a piece of it and a slip of zinc are applied to the tongue, 

 the well-known sensation produced by the passage of a weak 

 current of electricity will be felt. 



From the occurrence in the immediate neighbourhood of 

 the upper beds of the schistose rocks which underlie the lime- 

 stone formation of Perak, it would appear that the Kamuning 

 beds belong to the lower part of the calcareous series. It sh(.)uld 

 be stated, however, that the limestone which rests on the under- 

 lying beds, as far as has l)een observed in other parts of the 

 State, is not carbonaceous. Whether this is a sign of un- 

 conformity, or is simply due to local causes in operation at the 

 time of the deposition of these beds, is, in the pi'esent state of 

 our knowledge, impossible to determine. 



Limestones containing graphite have been found in Canada 

 and the northern parts of the United States. These rocks are 

 of the archoean period, and it is in them that the much disputed 

 Eozoun Cana dense occurs. 



In the schistose beds beneath the limestone, graphite has 

 been found at Batu Gajah, in the Plus Valley, near Tapali and 

 in Bernam. It is mostly disseminated in scales and grains 

 through the body of the rock, but at Batu Gajah there is a well- 

 defined vein of it. This vein was cut in making the new road 

 to Lahat, and more recently again in sinking a well in the 

 hospital grounds. 



A consideration of the characteristics of these schistose and 

 crystalline calcareous formations seems to point conclusively to 

 their belonging to the archoean period ; and it may be stated 

 that the whole of Perak, where the granitic rocks have not burst 

 through and come up to the siu'face, is ct)vered by beds of the 

 Laurentian formation, as no rocks of less age are known to exist, 

 except the very recent quaternary drifts and alluvial deposits. 



Ferak Government Printing Office. 



