67 



it is the alluvial that is worked first, the lode deposits being- 

 followed up later. Although a very small percentage of naetal is 

 sufficient to make tin lodes worth working under favourable 

 circumstances, they have not as yet proved very profitable in IS'ew 

 South Wales. It is owing to the abundance of alluvial tin, easily 

 worked by cheap Chinese labour, that the production of tin in the 

 East (Straits tin) has become so important. 



The collection of ores from Xew South Wales is very complete : {^oge QA 

 it is contained in three cases ; lode tin in 64, stream tin in 66, 

 clock specimens in 126. 



By far the most common parent rock for tin is granite. It is Lode Tin. 

 not certain to what extent the tinstone has been formed at about 

 the same time as the quartz, felspar, and other minerals of which 

 the granite consists, or has been introduced later by mineral-bearing 

 solutions or vapours. Other minerals similarly formed, and often 

 accompanying tinstone, are beryl, topaz, and tourmaline. Another 

 effect of these mineral-bearing solutions has often been the partial 

 destruction of the granite, more particularly of its f elspathic con- 

 constituent. While tinstone is thus frequently found irregularly 

 distributed in strings and patches through granite, it sometimes 

 occurs with quartz, occupying fissures or otherwise. These and 

 other features of the occurrence of lode tin are illustrated by the 

 specimens in this case. 



Deposits of lode tin are always found associated Avith granite or closely 

 allied rocks. The mineral contents of these lodes — compounds of 

 tin, fluorine, boron, &c. — are believed to have been derived from 

 the magma remaining after the crystallisation of the rock 

 containing them. 



Tin ores are widely distributed in New South Wales, but it is New England, 

 only in jSTew England that they occur in any abundance. Con- 

 sequently the greater part of this case is devoted to New England. 



The first few columns are reserved for crystallised specimens. 

 Although occasionally good, these crystals are not so abundant 

 or so perfect as those from Cornwall. 



