Vol. 65.] XAHAT ' PIPE' IN PERAK. 389 



Conclusion. 



To me, at any rate, it seems that a solution has been found to the 

 puzzle presented by this most interesting tin-ore deposit. If we 

 assume that the current of water going down the pipe was slow, 

 we can imagine that the released cassiterite was allowed to settle 

 down in the pipe slowly without being churned up and rounded, 

 as was the case in Jesophat's Valley. At the same time the con- 

 tinuity of lines of cassiterite, such as those shown in fig. 4 (p. 387), 

 would be broken. 



The evidence obtained from the specimen now in the British 

 Museum (Natural History) shows that some foreign material was 

 introduced. 1 



It is safe to assume, too, that when the original calcite-matrix 

 was dissolved, the level of the Kinta Valley was considerably higher 

 than it is at present; and it is probable that a considerable in- 

 crease in the percentage yield of cassiterite has resulted from 

 the settling-down of material in the pipe. The miner has probably 

 been assisted in this, while he certainly has been assisted by the 

 natural oxidation of the sulphides. 



The Lahat 'pipe' may be described in brief as a case of a 

 ' lode ' deposit being converted into a detrital deposit in situ. 



1 Taking into consideration the small size of the veins in this specimen, it is 

 probable that they are not part of the original deposit, but fissures formed in 

 the limestone by the surface-water and filled with ore from the main body of 

 stone in the pipe. Should this suggestion be correct, the specimen could be 

 regarded as a noteworthy example of simulation of ' lode ' conditions by detrital 

 material. 



Q. J. G. S. No. 259. 



