PetroLxjii and Geoloyi/ of Qiiee/ttstuivn. 145 



hocii ju-ospeeteil 1)l'1(iw 2(M> i'oi't , altlum^'h the records mention the 

 driving of :i tunnel fnuii I-'ein Tree (iully to prospect the Swedish 

 reef in depth, hut it is (h>ui)lfiil whether they ever worked this reef. 

 Messrs. Hirt nnd (terhuli liavt' recently driven a timnel from the 

 head of I'ohhler's (iully to cut the Swedish reef, hut at the time of 

 my visit, they a)>peared to have not Ijeen successful in locating it. 

 It is at least certain that there is no geological evidence in s\ipport 

 of the view that the gold docs not go down, and in the case of the 

 Swedish reef the possible occurrence of other rich patches of gold in 

 depth, has not been disproved. From the birth of this field the 

 reefs have been worked almost entii-ely by individual miners or 

 small parties, and companies were practically unknown. This is 

 prol^ably one important reason why the mines were abandoned at 

 such shallow depths. The presence of water and the need of pump- 

 ing macliinery. harder ground, increased liaulage, and the ditli- 

 culty of following such nari'ow reefs, all contended against the 

 enterprising individual, but such mines could, in many cases, Ijc 

 worked at a profit by small companies, with judicious expenditure 

 and economical methods of woi-king. 



4.— Summary and Conclusions. 



Until further palaeontological work has been attempted in this 

 area, no definite opinion can be expressed relative to the age of 

 these beds, near (^ueenstown. A stratigraphical comparison with 

 the strata at Diamond Creek and Yarra Glen, suggests that they 

 are intermediate in age between those at the above places, and 

 aie. theiefore, either Melbournian or Yeringian. It is, however, 

 possible that both series are i-epresented in the area dealt with in 

 this paper. 



Although diorite is a popular field name for many rocks in Vic- 

 toria, chemical and petrological examination show that true dioiites 

 are exceptional. The association of hornblende diorites. with gold- 

 bearing quartz in Eastern Australia, is not uncommon. The ex- 

 tensive nietasoniatic changes undergone by these rocks frequently 

 accompanies the introduction of the auriferous quartz. The Queens- 

 town diorite has been shown to Ijc closely allied to the Moining 

 Star diorite. Wood's Point, and has suffered similar alteratioi,. 

 Two independent types of metasomatic alteration can be recognised 

 in the Queenstown diorite — (1) A pi-opylitic alteration at relatively 

 high temperature and pressure, resulting in the formation of 

 chlorite and epidote after hoi-nblende ; the development of pyrrhotite 



11 



