Boulder-clays, Federated Malay States. 161 



must have been intruded when the bedded rocks were fresh and 

 unweathered deep below the surface, and the only solution seems to 

 be that the clay now exposed on the surface never resembled theUlu 

 Gopeng schists. 



In the earlier publication a section was described on the Kramat 

 Pulai mine. This was one of those rare cases where I had another 

 observer (Mr, W. 11. Jones) to check the accuracy of my sketch, 

 before the section was destroyed. Reference to it will show that if 

 the boulders are portions of a continuous hard bed broken up the 

 kaolin vein must have been broken up too, which is not the case.^ 



"Laterite" was mentioned above. This has an interesting bearing 

 on the question under discussion. When shales and schists are 

 weathered at the surface, generally, but not always, these masses 

 of ironstone are formed, and as the iron is gradually deposited 

 along bedding-planes and joints the masses exposed at the surface 

 frequently preserve the structure of the rock they replace and are 

 themselves a guide to. the nature of the country rock. In mining 

 operations these ironstone growths often give much trouble, as for 

 instance at Bruseh, and if the Kinta clays and boulder-clays were 

 weathered shales or schists one might reasonably expect to see 

 numbers of them in the soil or in mines where the soil has been 

 worked away. But such masses do not occur, as far as I know. 

 The clays are sometimes hardened by the deposition of iron, but 

 there is no shaley or schistose structure preserved. On the other 

 hand, where clearly bedded rocks occur, as at Redhills and near 

 Batu Grajah, ironstone replacements do occur, and in ditches near the 

 latter locality one can see how the ironstone is gradually deposited 

 as th.e shale weathers away. 



Another point to be considered is this. If we conclude that the 

 clays are formed by shale, etc., sinking over limestone as it dissolves 

 away, we should first be sure that there has been sufficient alteration 

 in the level of the limestone to produce the result. It is impossible 

 to obtain precise information, but although there are doubtless places 

 where deep cavities have been hollowed out, there is some evidence 

 pointing to the general lowering of the limestone surface having 

 been slight. 



Usually the limestone surface is a mass of pinnacles, but for some 

 time there was exposed, in the bottom of a mine at Tekka, Sungei 

 Raia, a large and almost flat platform of limestone that seemed to be 

 the original surface. Where the platform ended there were pinnacles 

 as in other localities. Again, at Gopeng, under the Gopeng Beds, 

 which show stratification, there is a limestone floor. This shows as 

 much irregularity as the limestone floor elsewhere, but the beds 

 above have retained their stratification, except immediately above 

 the soluble rock, where, however, a disorganized pebble-bed, if that 



' Mr. Jones now seeks to explain this vein as an effect of different colora- 

 tion in the clays, but if the Kramat Pulai vein can be thus explained the same 

 holds good for all the kaolin veins. I am quoted as describing a case at Fusing 

 Bahui which Mr. Jones says is similar, although he did not see it. It was, as 

 a matter of fact, different from the Kramat Pulai vein in that it had no sharp 

 boundaries and did not consist of kaolin. 



DECADE VI. — VOL. V. — NO. IV, 11 



