560 /. B. SCRIVENOR 



The form of the folding that led to the formation of the granite 

 ribs cannot yet be said to be fully elucidated. The strata older 

 than the granite are every^^^here much disturbed. In the least 

 disturbed area, the center of Pahang, the rocks are thrown into fairly 

 sharp anticlines and synclines: in other areas they are squeezed 

 together, pressed into a vertical position, contorted, and faulted. 

 There is reason to suppose that the granite invaded a number of 

 shattered antichnoria, but in two locahties there is some evidence 

 of overfolding, with the pressure exerted from the WSW. One of 

 these localities is in the Kinta District of Perak.^ Here the Carbon- 

 iferous Hmestone shows signs of great disturbance. Near Ipoh are 

 pinnacles showing excellent examples of fault-breccias; in one 

 crinoid-stems have been drawn out into threads in a thrust-plane. 

 But not far distant from these pinnacles is a cliff-section which 

 shows evidence of an overfold. The other locality is the western 

 slope of the Tahan Range in Pahang, where the dips show a prob- 

 ability of similar overfolding, but the evidence is not so clear as in 

 Kinta. However, these two localities are the only places known 

 to me where overfolding is evident or suspected. The balance of 

 evidence is of compressed, plicated, and faulted anticlines and 

 synclines. 



Faulting of the strata I beheve to have taken place on a large 

 scale, accompanied by "magmatic stoping." The evidence for 

 the latter will be mentioned in the more detailed description of the 

 coulisses. 



Denudation in Tertiary and recent times has laid bare the skele- 

 ton of the Peninsula, but it has not reached the granite or associated 

 plutonic rocks everywhere, therefore the Peninsula, apart from the 

 difficulties created by the vegetation, forms an admirable field for 

 observing the form of the upper limits of the granite ribs, and the 

 way in which the granite surface plunges along its strikes under 

 stratified rocks, is capped by them, emerges as small outcrops, or 

 sends out veins into the stratified rocks. 



In the northern portion of the map (Fig. 2), is seen the southern 

 end of the Nakawn coulisse. I have examined this only on the 

 PerHs border, and in what may be its prolongation in the Langkawi 



' Ipoh, marked on the map, Fig. 2, is in the Kinta District. 



