760 THE TIN-DEPOSITS OF NEW ENGLAND, N.S.W., I., 



tion is made into fissures, impregnations, stock works, bedded 

 deposits, etc. As, however, the form of an ore-deposit may have 

 little to do with its genesis, the latter method is considered 

 preferable for this paper. 



The deposits may be grouped for purposes of description into 

 eleven classes. Several of the classes merge into one another, 

 and, indeed, the same reef may at different places fall into two or 

 even more classes. Nevertheless, each class has its own special 

 characteristics, and it is considered better at present to make the 

 provisional classification rather more detailed than a final one 

 may need to be. 



The following is the proposed provisional classification : — 



Class i. — Quartz-quartzose veins. 



Class ii. — Quartzose. 



Class iii. — Greisen. 



Class iv. — Quartz-greisen. 



Class V. — Quartz. 



Class vi. — Quartz-felspar. 



Class vii. — Chlorite-deposits. 



Class viii. — Arsenical lodes. 



Class ix. — Pipe-deposits. 



Class X. — Cassiterite-veins in slate. 



Class xi. — Stannite deposits. 



Class i. — Quartz-quartzose Veins. 



This class is most abundantly developed at Elsmore, where, 

 indeed, it is the type-vein. The distribution of these veins has 

 already been referred to, and may be seen at a glance from text- 

 fig.2. 



The individual veins are seldom of any great length or width, 

 few being traceable continuously for as much as 10 chains. As 

 a rule, they either terminate by thinning out rather abruptly, or 

 by abutting on to a similar vein. 



The average width, as calculated from 105 determinations, is 

 10*5 inches. The greatest width is 3 feet, and the smallest veins 



