12 A SKETCH OF THE GEOLOGICAL STRUCTURE 



nature of the deposits themselves leaves little doubt in my 

 mind that they are approximately on the same geological 

 horizon as the Talchir Boulder Bed of India, and like it, were 

 connected with glaciers. 



In conclusion I will summarize what we can say we know 

 of the geological history of the Malay Peninsula. It has been 

 impossible to give in the space of this paper all the evidence 

 as it should be given, and I fear that in consequence some 

 statements may appear to require further investigation, but 

 I trust that it will be recognised that even in a jungle-covered, 

 tropical country information can be gathered that is of value 

 to those who care to enquire into the origin of such familiar 

 objects as the hills and valleys of the country we live in. 



1. In Carboniferous times the site of the Malay Penin- 

 sula was deep sea, lying off the coast of the now vanished 

 Gondwana-land. On the bed of this ,sea corals and shells 

 abounded, but periodical and violent eruptions of lava and ash 

 must have been very destructive to life. 



2. The sea-floor rose and about the opening of the 

 Permian period the coast of Gondwana-land had so far 

 advanced as to pour a huge accumulation of shallow water 

 sediments on to the deep-sea Carboniferous deposits, and 

 glaciers descended from the hills of this Gondwana-land coast, 

 which were of tin-bearing grariite depositing beds of clay and 

 boulder-clay that are now being worked for their tin-ore. 



3. The sea floor sank again and a pile of sediments was 

 deposited above the Gondwana shallow water beds, with the 

 result that they and the Carboniferous beds came to occupy a 

 position deep in the earth's crust where they were subjected 

 to great lateral pressure, resulting in close folding and the 

 formation of a series of arches, and they also were affected by 

 a large rise in temperature caused by their position in the 

 earth's crust and by the heat developed during the folding. 



4. The folding and consequent lessening of stability 

 allowed a vast rock-magma to rise from , the depths which 

 ultimately shattered and burst through the arches and solidi- 

 fied as our. well-known Mesozoic tin-bearing granite. 



Jour. Straits Branch 



