OF THE MALAY PENINSULA. 5 



were largely instrumental in determining the present config- 

 uration of the country. This was the case, and in order 

 to see how it came about, let us try to imagine what took 

 place in the earth's crust when the granite took up its present 

 position in relation to the older rocks. 



After the Gondwana rocks that are preserved in the hill 

 ranges had been deposited, sedimentation continued until the 

 calcareous Carboniferous rocks and the Gondwana rocks had 

 above them a huge pile of younger rocks. At the same time 

 lateral pressure was brought to bear on them, now deep down 

 in the earth's crust and at a high temperature, with the 

 result that they were to a large extent crushed into small 

 folds and bent as a whole into a series of low arches or 

 anticlines, the axes of which trended approximately north- 

 north-west, south-south-east, and were much longer than their 

 span. 



Below the calcareous rocks, and probably separated by a 

 considerable thickness of still older rocks was a vast molten 

 or viscous mass, laden with steam and other vapours, strugg- 

 ling to rise from the depths. This was the granite magma, and 

 the bending of the Gondwana and other rocks, the close fold- 

 ing with the consequent loss of stability as a lid to the granite 

 magma, enabled the latter to be forced upwards, partly by 

 pressure from other portions of the earth's crust, and partly 

 by the entangled steam. The granite magma rose underneath 

 a series of arches of which the points least able to resist the 

 attack of the rising mass were the apices. The tremendous 

 force pressed the molten mass against the under side of these 

 arches, the rocks that formerly were between the calcareous 

 rocks and the granite magma, had been broken up, sunk, and 

 perhaps completely dissolved in the latter ; the resistance to 

 the rising mass became less and less as pieces of the arch, 

 partially dissolved along planes of folds and faults, dropped 

 into the magma ; and finally the tops of the arches gave way 

 completely, they were broken up into blocks that slipped one 

 against another while huge masses dropped bodily into the 

 magma, allowing the granite to rush upwards and fill the 



R. A. Soc, No. 59.I9H. 



