162 Lieut. J. B. Scrivenor — Origin of Clays and 



be the correct interpretation of its peculiarities, can be traced into 

 clearly marked strata. If these deposits at Gopeng retain their 

 bedding, why do not the others do so also if they are only weathered 

 shale and schist ? 



Some mines have afforded exceptional facilities for studying deep 

 tin-bearing deposits, namely the Tronoh and Tambun mines. 

 The Tronoh mines contain shales and rich tin-bearing clay, and the 

 question is whether the latter are the shales weathered and broken 

 up over dissolving limestone or a distinct formation. It might be 

 argued with reason that taking this mine alone the former is the 

 better explanation and that the tin-ore was introduced by granitic 

 intrusions along the fault. I find it hard, however, to adopt this 

 view in its entirety. On the west are good sections of bedded shale 

 and quartzite, and I am informed that they carry only a little tin, 

 although granitic intrusions occur and also quartz veins, in one of 

 which wolfram has been found. Going eastward one comes suddenly 

 on clays without bedding, but with pebbles in some quantity and 

 very rich tin-contents. If the pebbles are derived from the harder 

 bedded rocks on the west and the quartz veins one would expect 

 them to be of greater size and more angular; and, moreover, seeing 

 that granitic intrusions occur in the bedded rocks it is difficult to 

 explain the comparatively large amount of tin-ore in the clay if it 

 all comes from granitic intrusions also. It might, however, be 

 suggested that the rich ore is derived from a long lode in shales, 

 now broken down to clay. I once saw a section in a small mine to 

 the south of the Tronoh Ltd. mine that might have been thus 

 interpreted, but nothing could be proved, and at the present time 

 there is nothing visible supporting the view. Nevertheless it may 

 be that some such interpretation as this is the correct one, and weak 

 points in the theory that the clay is a distinct formation overlying 

 the limestone are that nothing is known of it to the east underneath 

 the sand and masses of vegetation where the limestone rises nearer the 

 surface, nor has anything been proved concerning the presence of 

 tin-bearing clay under the bedded rocks on the west. 



In Towkay Chung Thye Phin's mine the distribution of the ore 

 is suggestive of a lode. On one side is the crystalline limestone, 

 coming near the surface of the ground. On the other side is a steep 

 bank cut in the shale and quartzite showing innumerable little 

 stringers of kaolin and veins with tourmalinized shale on either side. 

 The ore-bearing clay occurs along the junction of the limestone and 

 shale and quartzite. In the portion of the mine nearer the Tronoh 

 Ltd. mine it is a narrow Tjand of a few feet in width only. In the 

 gut in the centre of the photograph it is said to die out altogether. 

 Beyond it opens out again. 



In the Tronoh South mine again the run of the ore suggests 

 a lode rather than a detrital deposit ; but in all these Tronoh mines 

 there are objections hard to dispose of if we are to regard the 

 "Tronoh lead" as a weathered lode. In the first place, on the 

 west wall of the mines the effect of emanations from the granite is 

 seen in the tourmalinization of the shales bordering the small veins. 

 The shale is hardened and charged with minute crystals and grains 



