X INTRODUCTION. 



published by Mr. Scrivenor, notably one in the Quarterly Journal of 

 the Geological Society, vol. Ixix, p. 343, June 1913, from which I 

 condense the following brief account. 



The oldest rocks in situ are the limestone rocks of the Raub 

 series associated in Pahang with volcanoes. These, together with 

 some calcareous shales, are apparently of Carboniferous age. The 

 limestone rocks of the Malay Peninsula form detached masses on 

 both sides of the main masses of granite from the north as far south 

 as the Batu caves in Selangor on the west side and to Gunong 

 Senyum in Pahang on the east side; north of the Batu caves we 

 find these masses at Goping, Kwala Dipang, Ipoh, Lenggong in 

 Perak and Gunong Geriang in Kedah, and in the northern part of 

 our area a great part of the Lankawi islands and Terutau and many 

 rock masses in Perils near Kanga are of the same formation ; on the 

 east side we have also Gunong Senyum and Kota Glanggi in Pahang, 

 and Biserat in Jalor. Beyond our area we find great masses of 

 limestone running through Trang and southern Siam to Tenasserim, 

 Mergui, and up to Burma, the Shan States, Tonkin, and Laos, and 

 limestones of the same age are known to occur in Sumatra, Borneo, 

 Timor, and Rotti islands. 



From north of Alor Sta in Kedah commences the main granite 

 range which occupies the centre of the peninsula with outlying 

 branches to Penang, the Bindings, Gunong Keledang, and as far 

 south as Jelebu. Another granite ridge, the Benom Range, runs 

 parallel to this on the east side from south of Kelantan into Negri 

 Sembilan, and between these runs a range of foothills of quartzite ; 

 smaller granite ranges lie south of the end of the main range. 

 Quartzite hills occur from the Kinta Valley to the Klang river mouth, 

 and from the middle of Tringganu, including Gunong Tahan, lies 

 an outcrop of quartzite running to the south of Rumpin. The 

 quartzite forms also the main rocks of Pulau Tiuman and Singapore. 

 The hills of Bukit Timah and Bukit Mandai, however, are of granite. 



These quartzite masses are called by Scrivenor the Gondwana 

 rocks, while the granite is Mesozoic, dating sometime after the Trias 

 and before the Eocene period. The weathering of the main 

 Gondwana outcrop of quartzite and shales in Pahang accounts for 

 the large area of sandy country on this coast. 



Some Tertiary coal-deposits occur in Selangor, the flora of 

 which, so far as I have seen it, much resembles that of the present- 

 day Malay flora. 



The great alluvial flat on the west coast of Selangor and Perak 

 appears to be of very modern geological date. It extends westwards 

 from the main chain for about thirty-six miles to the sea and con- 

 sists mainly of stiff clays, generally yellow and ferruginous, con- 

 taining masses of ironstone, formed by the iron-depositing bacterium, 

 Crenothrix. The soil of the west coast-line, being thus argillaceous 

 with but few sandy spots, accounts for the large area of mangrove 



