﻿170 DR. W. E. JONES ON THE SECONDARY [vol. lxxii v 



According to the present 

 writer. 



4. Alluvial deposits derived from (2)' 

 and (3), and containing lignite, 

 peat, and tin-ore. 

 3. Granite. Age not definitely de- 

 termined. 1 

 2. Schists, phyllites, quartzites, and 

 indurated shales metamorphosed 

 by the granite of the Main 

 Range and of the Kledang 

 Range, and containing in places, 

 notably near the granite junc- 

 tions, granitic intrusions with 

 tin-ore in situ. 



These rocks have subsequently 

 suffered in places decomposition 

 to considerable depths. 



1. Limestone. Carboniferous to 

 Permo-Carboniferous, metamor- 

 phosed by the above granite. 



The main question on which I disagree with Mr. Scrivenor is 

 that of the original source of the ' clays and boulder-clays,' and of 

 the tin-ore which they contain. He includes these in his Gond- 

 wana Rocks, whereas I class them as alluvial deposits. 



Mr. Scrivenor is of opinion that some of the tin-ore is derived 

 from the granite and granitic intrusions now in situ in the district, 

 and that certain rich patches in the ' clays and boulder-clays ' have 

 received ' secondary enrichments ' from these intrusions ; but he 

 believes that the bulk of the tin-ore in his ' Gondwana Rocks ' is 

 derived 1 from an ancient tin-field quite unconnected with the 

 granite now in situ in the district.' In other words, the Kinta 

 district is stated to have furnished the remarkable phenomenon of 

 two tin-fields, one superimposed on the other, the latter being 

 of Permo-Carboniferous age, and the former of a much later 

 geological age. 



Limestone cliffs. — It is very important, in dealing with the 

 geological history of the Kinta district, to understand how the 

 limestone cliffs which stand well above the general level of the 

 valley have been formed. If it can be shown, as I endeavour 



1 I consider that there is strong evidence in favour of the view that the 

 granite of the Main Range of the Federated Malay States is a prolongation 

 southwards of that of Burma and Siam, and that it extends, with some breaks, 

 through Johore to Banka and Billiton. That of Burma is known to extend 

 across the borders of China, and in these areas it is, like that of Malaya, of 

 a very acid type and cassiterite-bearing. Further investigation may show 

 that this part of the world is occupied by some of the largest masses of 

 granite, intruded at the same period, on the earth's surface, and that the 

 igneous activity resulting in the intrusion of this granite determined the sub- 

 sequent main structure-lines of that part of the Far East. 



According to Mr. Scrivenor. 

 4. Lignites and recent deposits. 



3. Mesozoic granite, probably Cre- 

 taceous. 

 2. Gondwana Rocks : 



(Older than the granite). 

 ■y I Schists, phyllites, 



ounger j q uar ^ z ites,and shales. 

 (Metamorphosed by the granite) 



I" Clays and boulder-clays 

 Older < correlated with the 

 |_ Talchirs of India. 

 These latter contain tin- ore, 

 ' the bulk of which is derived 

 from some mass of tin-bearing 

 granite and rocks altered by it, 

 but distinct from and older than 

 the Mesozoic granite.' 

 1. Carboniferous Limestone meta- 

 morphosed by Mesozoic granite. 



