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varying from the tabular, though often irregular or 

 lenticular, vein which may be traced several hundred feet, 

 to mere veinlets, often only a fraction of an inch in width 

 and a few feet in length, which ramify through a rock that 

 has been subjected to small irregular fissuring. This latter 

 variety is well illustrated in the fissuring of ankerite bands, 

 so characterictic of some of the gold deposits of Porcupine. 

 Irregular and lenticular bodies of quartz often occur which 

 may have a width of ten or twenty feet, but which die away 

 in a distance of fifty feet. Again, there are dome-like masses 

 of quartz which are elliptical or oval in surface outline. In 

 some parts at least these masses can be seen in contact with 

 underlying rocks at a low angle, which would suggest that 

 they are broad lenticular masses which have filled lateral 

 fissures in the country rock. The most conspicuous dome 

 masses are those of the Dome property, where the two 

 largest are about 125 feet by 100 ft. A fissure may be 

 vertical and regular at some points. At others it may 

 incline at a lower angle to the horizontal or take on a more 

 or less lenticular form. 



The term " vein " as here used is not confined to the 

 filling of a single fissure with well-defined walls, for this 

 type of vein is rather the exception in the Porcupine area. 

 The fissuring has been so irregular that a " vein " in one 

 part may consist largely of quartz, and in another part of 

 numerous veinlets of quartz and intervening schist, re- 

 sembling a stockwerk; again, the main part of a vein may 

 be almost vertical in attitude, but many veinlets, branches 

 from the main vein, may extend laterally into the country 

 rock. It is often found that the values are obtained in 

 parts of the vertical vein which have been subjected to a 

 later movement and enrichment, whereas the lateral veins 

 have little or no value. This is illustrated in the No. 1 

 vein at the Rea mine. 



The relationship of the strike of the veins to that of the 

 enclosing rock is often difficult to determine, since generally 

 along the veins there has been shearing of the country rock 

 which may conform to the general direction of the strike of 

 the veins. However, by determining numerous strikes in 

 the schist away from the veins, it is seen that the majority 

 of them are inclined to the strike of the enclosing rocks. In 

 dip the veins vary from vertical to nearly horizontal. In 

 No. 1 shaft of the Hollinger the vein is practically vertical, 



