FiNLAYSON. — Geology of Quartz Veins of Otago Goldfields. 



75 



east and dipping south-east at an angle between 10° and 25°. The walls 

 are fairly defined with seams of gouge, and the vein has been opened up 

 for nearly two miles along the strike, but the workings are now inaccessible. 

 Its thickness varies ; in places it is no more than 2 ft., but the average 

 distance between walls is about 10 ft. The rusty quartz from near the 

 surface was in patches extremely rich, while the deepest levels (200 ft.) 

 averaged from 7 dwt. to 12 dwt. per ton. The quartz is, in general, seamy, 

 and distinctly banded by parallel streaks of pyritic matter. The quartz 

 shoots may occupy the whole width of the vein or only a short width on 

 either wall. The dip of the shoots is regular and characteristic, although 

 they generally wedge out in lens fashion when followed down, to make 

 again on the same track at a greater depth. 



Microscopically the quartz is mostly fine-grained, with occasional coarse 

 granules enclosed in it, giving a pseudo-porphyritic structure. Frequent 

 strings and veins of calcite are present, and the mass of fine-granular quartz 

 is crowded with pyrite. Evidently the quartz is very largely a result of 

 replacement, and the very distinct banding occasionally seen is best ex- 

 plained as due to progressive replacement of sheeted rock by ore. 



In general the vein bears strong resemblances in structure to those of 

 Skipper's and Macetown. A fuller description is given by Mr. T. A. Rickard 

 in a very graphic article.* 



Canton Vein. — This is similar to the last. It lies close to that one, and 

 strikes in a direction to join it, the probable junction lying in a gravel-filled 

 basin. These two veins in their field-relations may be compared with the 

 tAVO branches of the Nugget and Cornish vein. 



Bella Vein. — This lies four miles from Waipori Township, in Long Gully, 



a branch of the AVaipori River. It strikes 

 east and west, and stands almost vertically. 

 It has fairly defined walls, and varies from 

 3 ft. to 5 ft. in thickness. Where exploited, 

 it consisted at the surface of a shoot of 

 payable quartz from wall to wall. This 

 block was stoped out for a depth of 50 ft. 



when it ran over to one wall and wedged 

 Ym. 2.— Section of Bella Vein, o^it, although the width between walls was 



maintained. The vein carries a little scheel- 

 ite, which is found in some quantity in several little-known veins in this 



district. 

 Cox^s 

 four miles from Waipori in a northerly direction. On the line of fissure, 



Vein. — This lies on the flanks of the Lammerlaw Ranae, about 



o^> 



Vci )i F/S3' 



Fig. 3. — Sketch-plan of Cox's Vein. 



which strikes about east and west, and stands vertically, two shoots of stone 

 were opened out on the surface, dignified by the names '• Maori " and 

 " Maud," with a contraction of the fissure between them. 



* Rickard, " Goldfields of Otago," Trans. Amer. Inst. Min. Eng., vol. xxi. ]>. 416. 



