BY LOFTUS HILLS, M.B E., M.SC. 141 



& M. Mine, Moina. The description of this rock and the 

 structure, composition, and paragenesis of the lodes are pre- 

 sented in Geological Survey Bulletin No. 12. The origin is 

 assigned to the adjacent Epi-Silurian granite, which gave 

 rise to the garnet-magnetite rock as a contact metamorphic 

 rock as a metallogenic phase preceding the tin-wolfram-bis- 

 muth phase. 



The galena ore-bodies at Round Hill are also assigned 

 to the same source as their origin, and are shown to have 

 a saddle structure similar to the Bendigo saddles. They are 

 assigned to an outer zone of the tin phase of the Epi-Silurian 

 metallogenic epoch. 



A. Mcintosh Reid has described in Bulletin No. 30 the 

 wolfram and copper deposits of the Pelion District. In the 

 relatively undeveloped state of these deposits complete de- 

 scriptions are not possible. The genesis of the wolfram 

 is definitely assigned to the Epi-Silurian granite, but the 

 evidence for the age determination of the copper deposits 

 is not as conclusive. 



(11). The Ore Deposits of Scamander. 

 These are described by the late W. H. Twelvetrees in 

 Bulletin No. 9 of the Geological Survey. The structural 

 features and composition are described, and they are grouped 

 as follows: — 



(1) Wolframite and Cassiterite Veins; 



(2) Arsenopyrite-quartz-chalcopyrite lodes; 



(3) Arsenopyrite-quartz-argentiferous lodes. 



The distribution of these groups is interpreted as in- 

 dicating a zonal precipitation outwards from the Epi-Silu- 

 rian magmatic hearth in the order indicated above. 



(12). The Osmiridium Deposits. 



The occurrence of osmiridium in alluvial deposits has 

 been known for many years, and its origin from serpentine 

 was regarded as almost proved, but it was not until the year 

 1913 that this mineral was definitely established as being 

 an original component of the serpentine rock. In that year 

 the discovery of what were termed "osmiridium lodes" was 

 responsible for the examination of the Bald Hill area by 

 the late W. H. Twelvetrees, and as a result of this investi- 

 gation the occurrence of osmiridium as a constituent of ser- 

 pentine was definitely established. This is described in Geo- 

 logical Survey Bulletin No. 17. 



