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ECONOMIC GEOLOGY 



of the most important fields. This valley is about 40 miles in 

 length, and averages about 15 miles in width. The amount of 

 tin in some deposits is sometimes 20 per cent. The tin-bearing 



alluvium is called karang. This material is often cemented 

 together by limonite. 



The kong is the term applied to materials having two modes of 



