STRUCTURAL GEOLOGY OF BRITISH MALAYA 561 



Islands. A view of the Nakawn hills, however, from the railway in 

 Siamese territory, suggests that they are granite. On the Perils 

 border granite is found in the north (Gunong China, 2,370 ft.), but 

 it plunges under a thick cover of limestone, which forms rugged 

 hills along the border to the sea. This range of limestone hills 

 contains, near the granite, deposits of tin-ore that are worked in 

 caves. It curves sHghtly toward the west before it reaches the sea, 

 which suggests that the similar rugged hmestone hills of the Lang- 

 kawi Islands are part of the same coulisse. In these islands, how- 

 ever, granite reappears in Gunong Raya (2,888 ft.) and other 

 outcrops. 



The Kedah-Singgora Coulisse (No. 2) is a broader range of shale 

 and quartzite hills of no great altitude, in which a few outcrops of 

 granite have been found, but Bukit Tinggi, the principal peak 

 (2,525 ft.), is formed of the sedimentary rocks. Tin and wolfram 

 deposits in its neighborhood prove, however, that granite cannot 

 be far below the surface. These hills extend northward to the 

 China Sea, and are crossed in Siamese territory by the railway to 

 Kelantan. Cuttings on this railway show a large granite outcrop 

 between outcrops of quartzite. 



South of the range are isolated outcrops which may have once 

 been continuous with it, but have been separated by marine denuda- 

 tion, converting them into islands in a sea covering the plain of 

 Kedah and Province Wellesley. The first of these (No. 3) is Gunong 

 Perak (2,823 ft.), an isolated granite mass. Number 4 is a more 

 imposing mountain, Kedah Peak or Gunong Jerai (3,978 ft.), 

 formed of quartzite with granitic intrusions. Penang (No. 5) is 

 still an island. The only rock other than granite that I have seen 

 there is dolerite, and I have not seen that in situ. The main mass 

 of the island is certainly granite, rising to 2,722 ft.; but to the 

 southeast are two small islands of sedimentary rocks. In Province 

 Wellesley are granite hills with a few of sedimentary rocks also. 



The Bintang Coulisse (No. 7) is the first large granite range in 

 this part of the Peninsula. It has been broken by marine denuda- 

 tion between Taiping and the Bindings, and farther north, between 

 Gunong Bintang (6,103 ft.) and Gunong Lang (3,750 ft.) is a com- 

 paratively low tract of stratified rocks, the granite being seen only 



