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DB. W. E. JONES ON THE SECONDARY [vol. lxxii, 



EXPLANATION OF PLATES XIII-XV. 

 Plate XIII. 



View of Kramat Pulai Mine, Kinta (P.M.S.) : a band of lignite interbedded 

 with the ' clays and boulder-clays.' Corundum ' boulders ' and tin-ore 

 occur in the clays above and below the lignite. 



Plate XIV. 



View of Lahat Mine, Kinta (F.M.S.). On the left the mica-schists are seen 

 in contact with the granite of the Kledang Range. On the right the 

 deposits are of alluvial origin. The limestone bed-rock is seen cropping 

 out at the bottom of the mine. 



Plate XV. 



Geological sketch-map of the Kinta district on the scale of 3 miles to the 

 inch, or 1 : 190,080 ; and section across the Kinta district from Gunong 

 Irau to Gunong Hijau on the same horizontal scale. 



Discussion. 



The Peesident (Dr. A. Smith Woodwabd) compared the 

 phenomena described by the Author with those observable on the 

 coast of Brazil, especially in the neighbourhood of Rio de Janeiro, 

 where the deposits originally supposed to be of glacial origin were 

 really the decomposition-products of the granitic rocks in situ. 



Dr. J. W. Evans remarked on the sharp opposition between the 

 views put forward by Mr. Scrivenor and those advanced by the 

 Author. The former had done very valuable work in the Malay 

 Peninsula, but the speaker thought that the latter had made 

 out a strong case. His explanation of the structure of the 

 country had the advantage of simplicity in comparison with that 

 adopted by Mr. Scrivenor, and received strong support from the 

 evidence adduced of the relation of the distribution of the 

 minerals in the Gropeng Beds to the occurrence of the same 

 minerals in the adjoining intrusive and metamorphosed rocks. 

 The suggestion that the unstratified character of these deposits 

 was the result of landslips was in accordance with the speaker's 

 own experience in South America. When the rocks of steep 

 slopes were converted into soft clay-like products by tropical 

 weathering, there came a time when the weight of the altered 

 material became too great to be supported by the cohesion at the 

 surface of the unaltered rock, and it slid forward into the valley 

 below. 



Prof. W. W. Watts congratulated the Author on the results of 

 his three years' work in the Federated Malay States. The exhibited 

 specimens, maps, and statements seemed to make out a very good 

 case for his explanation of the origin of the tin in that region — an 

 explanation which appeared to be in accordance with what was 

 known of stanniferous deposits elsewhere. He hoped that the 

 Author would follow up his researches on tropical weathering. It 

 was possible that weathering under subtropical conditions in the 



