RUBIDGE — ON METALLIFEROUS SADDLES. 



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in fig. 3. The points a and c, were not three feet apart ; the line 

 f. g., about an inch thick, was micaceous rock with large crystals 

 of felspar. The richest deposits of ore seemed to me to occur at 



Line of Strike. 



Fig. 3.— Koperberg. 

 h i, direction of the metallic axis ; k I, strike of the rocks ; dip towards h i. 



spots on the saddles or axes where one or more of these twists met 

 them. There was generally no metal in the twists. The axes too 

 were traceable for miles through the country, but were only metalli- 

 ferous, to any considerable extent, at intervals. Thus, I believe the 

 mines of Springbok Vontein and Koperberg were on the same run — 

 a good section of which was visible on the side of a ravine crossing 

 it nearly at right angles near Koperberg. This showed that these 

 disturbances were not produced by, nor essentially connected with, 

 granite. The meeting of a twist with the saddle of Koperberg I 

 have mentioned. I believe more than one crossed that of Springbok 

 Vontein, though the surface was so decomposed and so scarred and 

 fissured in various directions that it was impossible to make it out 

 clearly. This mine had not been worked to any great depth when 

 I visited it. The observations on the succession of ores, though I 

 believe it applies equally to this, was made at Concordia and other 

 places. 



At Nababeel, a spot which has not produced so much ore as its 

 appearance promised, was observed the structure shown in fig. 4. 



