146 



ME. J. B. SCEIVENOE ON 



[June 191 2, 



rendered the underlying limestone crystalline, and converted the 

 beds above into phyllites and quartzites, one might reasonably 

 expect to find some well-marked characteristic due to regional meta- 

 morphism in the beds lying between the altered rocks. ^N'o such 

 characteristic, however, is observable, and its absence is probably 

 due to the great plasticity of the material acted upon, which enabled 

 the beds to adjust themselves to the strains in the earth's crust 

 without great development of heat. In two sections I have seen 

 what might possibly be described as ^ the shadow of a schistose 

 structure 'in a much-weathered rock, but I have observed nothing 

 conclusive in this direction. Therefore., if any marked characteristic 



Fig. 3. — Diagrammatic section in Kinta Tin-Mines^ sliowing 

 disturbance of ' glacial clays ' and ' hoidder-clays.' 



A 



o\ 

 \ 



\ 



\ \. 



\ 



a 



O 

 o 



\ 



o 



\ 









o, 



^^n^ 



was ever imposed on the Gopeng Beds by regional metamorphism, it 

 must be assumed that the characteristic has been destroyed by the 

 weathering action of ground water. This is not very probable, 

 because immediately one passes up to the overlying phyllites and 

 quartzites, a schistose structure in the former is at once obvious, 

 while it is sometimes present in the latter. 



It is also remarkable that no quartz-veins have been observed 

 in the Gopeng Beds away from the granitic intrusions mentioned 

 above and the granite margin. 



The only result of the earth-movements which affected the lime- 

 stone and the other rocks that can be observed in the Gopeng Beds 

 is the faulting ; but, at the same time, it must be remembered 

 that some slight derangement of the beds would be caused by the 

 recent solution of the limestone below by underground water 

 and the consequent settling-down of the clays and boulder-clays. 



