228 STREAM TIN DEPOSITS OF PERAK. 



pore, where the paleozoic clays and granite are found side by .side, 

 the answer is that there are no drifts. The reason of that is that 

 there are no high mountains near to give rise to them. Small 

 quantities of tin have been found at the junction of the clays and 

 granite at Singapore, sufficient perhaps to justify the conclusion 

 that had they been subjected to the action of ruuning water and 

 mountain streams for ages, large deposits of stream tin would 

 have resulted. 



At the same time, 1 do not suppose that all the granite at 

 its junction with some overlying formation is equally rich. Gene- 

 rally it is rich. There are doubtless barren granites here as else- 

 where, but they seem to be fewer here than elsewhere. 



It is a remarkable fact in mining for tin that stream tin ore 

 and mineral veins or lodes of tin are seldom found together. I say 

 seldom, because I am not so sure about the experience of Europe, 

 but I might say never, as far as experience teaches us in Australia 

 and in this county. The richest tin lodes in Australia (Herber- 

 ton) have no stream deposits anywhere near them. I should say 

 that the causes which made the tin segregate into lodes were more 

 energetic than those which condensed it loosely on the edges of an 

 overlying formation. This, however, is theory. What my expe- 

 rience teaches me as certain is, — first, that stream tin is not derived 

 from lodes or veins ; and secondly, that lodes or veins do not decom- 

 pose into anything like stream tin. 



Now let us, in conclusion, examine the sections presented by 

 the tin mines at Thaipeng, and see how far these will bear out 

 those inferences. First of all, we meet with loamy clay or black 

 vegetable mould, full of roots, branches, stumps of large trees in 

 the positions in which they grew, besides prostrate stems of trees. 

 Half of this black deposit is w^ater, and half the remainder is vege- 

 table matter that wall burn. Underneath are layers of white, red 

 and yellow sands, mixed with coarse layers of quartz and felspar. 

 There are also occasional deposits of red clay. 



By the aid of the microscope we find that the sand is derived 

 from granite and deposited in fresh water. If you examine it 

 closely, you will see that the grains are all angular and transparent. 

 When the polariscope is applied to them, we find a magnificent 

 play of colours. By the same instrument we are enabled to dis- 

 tinguish a few fragments of felspar and fewer still of mica. A 

 little experience enables one to pronounce at once that this sand 

 has come from granite. If it had been derived from a volcanic 

 rock, the quartz would be glassy and not give the play of colours 

 that we observe here. 



