Vol. SS.I THE GOPENG BEDS OF KINTA. 151 



leaves, while on the trunk were marks that the manager of the mine 

 and myself agreed were cuts made by an axe or some such instru- 

 ment (see fig. 5, p. 150). Again, at Tekka a tree-trunk and mass 

 of leaves, in very fair preservation, were found actually embedded 

 in soft granitic rock in situ, but with a casing as at jS"ew Gopeng. 

 These could not possibly have reached their present position until 

 the granite had solidified and cooled, and it is difficult to see how 

 they could have done so afterwards by purely natural agencies ; 

 therefore I have no doubt now that these trunks reached their 

 present position by falling down old, long-forgotten excavations, 

 and that the latter were filled in by detritus from the surface. 



(7) The Cassiterite in the Gropeng Beds. 



Owing to the great irregularity of the limestone surface, it 

 is impossible to give a definite figure for the thickness of the 

 Gropeng Beds : 200 feet from top to bottom would probably be 

 near the mark ; but the feature to be emphasized here is that, from 

 top to bottom and over the whole area comprised in the map, no 

 sample has been properly examined that has not been found to 

 contain tin-ore. This is the experience of every English-speaking 

 miner in the district, and I believe of every other miner who has 

 sampled his ground carefully. 



The bores that I put down in 1910 bring out this point ex- 

 cellently. In clay from one bore the amount of tin-ore was so small 

 as not to be worth estimating. In the others it ranged from "1 of 

 a kati (1 kati = l'33 lb.) to over 8 katis per cubic yard. Most of the 

 bores reached the limestone or the ironstone capping it, and not 

 one sample (taken every 2 feet) failed to afi'ord tin-ore. 



The condition of the cassiterite is like that of the rest of the 

 sand. The grains are angular with the edges smoothed off, but 

 very rarely masses of cassiterite are found which must be regarded 

 as boulders in the boulder-clays. 



A few were found on the Kinta Tin-Mines land last year, and 

 proved to be a remarkable form of cassiterite containing so much 

 iron as to be lifted by an electro-magnet. Another was presented 

 to me long ago by M. Legros, of the Societe des Etains de Kinta. 

 Unfortunately I did not know at the time from which beds it came, 

 •and the boulder was broken up ; but I remember it very well as it 

 was originally, on account of its great weight, which was well 

 over 100 lbs. 



My experience of the Gopeng Beds convinces me that the bulk 

 ■of the tin-ore — to be precise, all, except part of that found at the 

 -granite junction and near the kaolin veins, — is an original constituent 

 of the beds and therefore older than the Mesozoic granite ; but, as 

 others may find some difficulty in accepting this conclusion from 

 Avhat has been said above, I give briefly the reasons that have led 

 me to it. 



If this cassiterite is not an original constituent, then it, with the 

 tourmaline and topaz, must have been formed by impregnation from 



