﻿172 



DR. W. B. JONES ON THE SECONDARY 



[vol. lxxii, 



into the granite, relatively less than the isolated hills, would be equal 

 to the present height of these hills above the general level of the 

 valley-floor, which is formed of the same limestone. Two of these 

 hills are well over 1500 feet above the limestone floor, so that it 

 must be presumed that the valley sank into the granite magma at 

 least that much more than did the limestone constituting these 

 hills. No reason is given why the limestone floor of the valley 

 should sink into the granite magma, and leave these limestone- 

 hills as isolated heights. 



That a granite magma is able to incorporate huge blocks of 

 limestone, several hundreds of feet thick, over an extensive area 

 is a highly controversial postulate ; but, where no evidence is given 

 of the presence of large quantities of calcic minerals in the granite, 

 even in the neighbourhood of the limestone, the explanation cannot 

 be considered satisfactory. Moreover, the presence here of numerous 

 big veins of pegmatite, aplite, and quartz, which represent the 

 later phase of the granite intrusion, seems to show that the residual 

 magma had not incorporated great masses of limestone. 1 This 

 interesting question of magmatic stoping need not, however, be 

 further discussed here. 



Most of these hills are on the east side of the Kinta Yalley, and 

 there is not a single limestone hill on the west side. It is a very 

 significant fact that, practically without exception, these hills lie 

 between two or more rivers or streams, and that there is an intimate 

 relationship between the position and form of these hills and the 

 drainage- system of the valley. Taking the masses from north to 

 south, we note the following sequence : — 



(a) Gunong Kantang (1087 feet) is between a tributary of the Sungei Pari 



and Sungei Kantang. [' Sungei ' is Malay for ' river ' or ' stream.'] 



(b) Gunong Kuang is between Sungei Kuang and Sungei Kantang. 



(c) The cliffs north of Ipoh (Gunong Lang, Gunong Tungun, Gunong 



Santan, and Gunong Tasek) are between Sungei Pari and Sungei 

 Kinta. 



(d.) Gunong Temiang is near the confluence of Sungei Kinta and its tributary 

 Sungei Choh. 



(e) The cliffs east of Ipoh are between Sungei Choh, Sungei Ulu Piah, 

 and Sungei Kinta. 



(/) The Gunong Lanno mass, near Pidai, is between Sungei Raia and Sungei 

 Tekka. 



(g) The largest mass of all, including Gunong Gajah, Gunong Nasi, and 

 Gunong Tempurong north-east of Kuala Depang, is between Sungei 

 Karnpar, Sungei Depang, and Sungei Siput. 



On the west side, where the watershed of the Kledang Range is 

 only from 3 to 4 miles from- the valley-floor, there is but one 

 stream, the Sungei Jahan, and this is a very small one. The 

 absence of limestone cliffs and of streams on this side of the valley, 



1 J. J. Sederholm, C. E. Congres Geol. Intern., 12eme Sess. (Toronto, 

 1913) 1914, p. 319 ; and J. P. Iddings, ' The Problem of Vulcanism ' Yale 

 University Press, 1914, pp. 200, 201. 



