110 C. GOULD ON A RECENT DISCOVERY OE TIN-ORE IN TASMANIA. 



The basalt on the east in places extends right up to, and rests 

 directly on, the porphyry. 



Large quantities of what, in the absence of a better term, may be 

 called stream -tin have been already obtained; and the amount will 

 be much increased when an effective water-supply has been provided 

 and the primitive mode of washing, at present employed, aban- 

 doned. 



This alluvial tin has not been subjected to the action of the run- 

 ning of the water of brooks, but is procured from the shallow sur- 

 face-drifts resting on the flanks of the mountain, and is derived 

 directly from the disintegration of veins and strings of ore dissemi- 

 nated through the porphyritic rock. 



This latter contains oxide of tin, in small veins in irregular 

 bunches, upon joint faces, and, as I also anticipate, will prove to 

 be the case in large deposits in true lodes. 



Gossany outcrops of lodes or irregular deposits occur of great 

 extent in places ; and in these are met with ferruginous agglomera- 

 tions of minute particles of tin-stone, forming projecting boulder 

 surface-masses of great size. Nuggets (as they are locally termed) 

 or shoad-stones of rich tin -ore are freely discovered, varying up to 

 four or five hundredweight in size. 



Surface-indications of large lodes are also seen, in which a clayey 

 material is traversed by strings of galena, of iron pyrites, and by 

 large quantities of carbonate of iron ; no attempt has yet been made 

 to ascertain their nature or develop them. 



Unquestionable lodes in the adjacent slaty rocks contain antimony 

 and zinc blende. The average direction of those yet discovered is 

 from 10° to 20° to west of north, and east of south. 



I regret that the brevity of my stay at Mount Bischoff, and the 

 undetermined character of the main deposits of ore, prevent me from 

 at present giving fuller details of what will, I think, prove to a very 

 important discovery. 



