﻿Vol. 66.'] TOURMALINE-CORUNDUM ROCKS OF KINTA. 435 



18. The Tourmaline-Corundum Kocks of Kinta (Federated 

 Malay States). By John Brooke Scrivenor, M.A., F.G.S., 

 Geologist to the Federated Malay States Government, and 

 formerly of H.M. Geological Survey of the United Kingdom. 

 (Read December 1st, 1909.) 



[Plates XXX & XXXI — Microscope-Sections.] 



Contents. 



Page 



I. Introduction : Previous Literature 435 



II. Main Features of the Geology of the Kinta Valley 436 



III. Description of the Tourmaline-Corundum Rocks and the 



Associated Schists 438 



IV. Origin of the Tourmaline-Corundum Bocks 444 



V. Conclusions 447 



I. Introduction : Previous Literature. 



I propose in the following paper to describe and discuss the origin 

 of certain rocks, remarkable alike in mineral composition and in 

 structure, found in the Kinta Valley of Perak, the premier 

 tin-field of the Federated Malay States. The two chief ingredients 

 of these rocks are tourmaline and corundum ; and it is evident,, 

 from the geological structure of the district, that they are the 

 result of extreme metamorphism in beds associated with schistose 

 rocks found chiefly on the west side of the valley, and perhaps- 

 also in thin beds intercalated with the crystalline limestone that 

 generally forms the bed-rock of the tin-mines. 



The previous literature dealing with the Kinta Valley, or, indeed, 

 with Perak as a whole, is very scanty, and does not take long 

 to review. 



In 1882 M. J. Errington de la Croix "' described the geology 

 of the Malay Peninsula (pp. 9-20), noticing the Kinta limestones 

 as being widely developed. 



In 1884 the Bev. J. E. Tenison-Woods 2 said that the granite 

 ranges of Perak are flanked by ' Lower Limestone ridges ' forming 

 detached hills about 1500 feet high. 



' The limestone is crystalline, without a trace of organising], though lines of 

 stratification can still be traced. . . . There is a Palaeozoic sandstone, clayslate, 

 or gneissose formation lying between the limestone and [the] granite. It is 

 much decomposed, and gives rise to a red clay which generally goes by the 

 name of laterite.' 



In the same year the same author 3 mentioned an instance of a 

 recent volcanic rock in Kinta, which appeared to be a basaltic dyke. 



1 ' Les Mines d'Etain de Perak (Presqu'ile de Malacca) ' Paris, 1882. 



2 ' Geology of the Malayan Peninsula ' Nature, vol. xxx, p. 76. 



3 ' Physical Geography of the Malayan Peninsula ' Ibid. vol. xxxi, p. 155. 



