GEOLOGICAL HISTORY OF THE PLATKAU. 477 



copper-mines they contain. 8iV>umbun is a peak of 

 greenstone rising out of syenite. Westward, one 

 passes from tlie granite into marble, and then on to 

 a sandstone of a late foimation, which contains layers 

 of coal that is probably of the same age as that I saw 

 at Siboga. 



The whole geological history of this part of Su- 

 matra may be summed up as follows : On the syenite 

 and granite, layers of mud and coral were deposited ; 

 then the whole was raised and plicated; and after 

 this period was deposited the sandstone, the strata of 

 which we have already noted as being unconfonnable 

 to the rocks on which they rest, and more nearly hori- 

 zontal. If, as Mr. Van Dijk thinks, and is very prob- 

 alole, the nmrble in the cleft of Padang Pangjang is 

 fonned from corals, at least not older than the eocene 

 age, it follows that the mountain-ranges of Sumatra 

 have been fonned within a comparatively recent pe- 

 riod, Tlie process of covering these strata by lava, 

 pumice-stone, and volcanic sand and ashes, has been 

 going on since historic time. 



The most remarkaljle thing in this kampoug of 

 Sinkara, is the h(d% or town-hall. Either end, on 

 the inside, is built up into a series of successive plat- 

 forms, one rising over the other. On the outside these 

 elevated ends resemble the stern of the old three and 

 four decked frigates which the Dutch generally used 

 when they first became masters of these seas, and such 

 as can yet be seen used as hulks in the ports of the Brit- 

 ish colonies. The exterior of the hali^ as well as the 

 better private houses, are painted red, and ornamented 

 with flowers and scroll-work in white and black. 



