Vol. 69.J GEOLOGICAL HISTORY OF THE MALAY PENINSULA. 3-19 



Later than the Mesozoic Granite, and unconformable on the 

 Gondwana rocks, are some Coal Measures of Tertiary age which 

 crop out in Selangor. Dykes of dolerite which cut the Mesozoic 

 Granite are believed to be of Tertiary age also. 



The only recent deposits that will be dealt with here are deposits 

 of lignite and sand overlying glacial clay and limestone in Kinta, 

 as also some interesting torrential boulder-deposits. 



IV. The Rattb Series. 



The llaub Series is calcareous throughout, but for a few shales 

 that do not effervesce with acids, and is best seen in the valley of 

 the Pahang River and its tributaries. It comprises limestone and 

 shales with a greater or less percentage of lime, and there is reason 

 to suppose that some of the shales contain a certain amount of 

 very fine volcanic ash, which betrays itself by a buff coloration, 

 while the ordinary shales are deep greyish-blue. Some of the 

 shales contain carbon. 



The limestones range in colour from white, through grey, to 

 black ; occasionally they are reddish. The black limestones contain 

 carbon in quantity. Even in cases where organisms can be easily 

 distinguished, the limestones are to a large extent crystalline. 



On the west of the Main Range the limestones are markedly 

 crystalline, and only crinoid-stems and other obscure fossils have 

 been noted. 



In the Kinta Valley the limestone is exposed as well as could 

 be desired in the limestone-hills, and in the mines in the floor of 

 the valley. In some places it also rises as smooth-surfaced pinnacles 

 above a thin layer of soil, and in the pinnacles evidence has been 

 found of disturbances on a large scale. 



The only point that need be noted here, concerning the alteration 

 of the limestone by the Mesozoic Granite, is the rarity of tourmaline 

 as a product of metamorphism. 



V. The Chert Series. 



I need not repeat here the description of this series given 

 in the 'Geology & Mining Industries of Ulu Pahang' (pp. 35- 

 37) and in the ' Geological Magazine.' 1 The most important point 

 to notice is that the available evidence shows an unconformity 

 between the Chert Series and the Gondwana rocks. 2 



VI. The Gondwana Roots. 



Apart from the glacial clays, these rocks are best seen in 

 Pahang, where fossils have been found near Kuala Lipis and on 

 the Benta-Kuantan road, but fossils have also been found in Perak 

 and Singapore. At first, these rocks were called provisionally the 



1 ' Radiolaria-bearing Rocks in the East Indies' Geol. Mag. dec. 5, vol. ix 

 (1912) pp. 241^8, 



2 Ibid. p. 244. 



