192 THE VERMILION IRON-BEARING DISTRICT. 



and most difficult. It is believed that the relations between the greenstones 

 and iron-bearing rocks have now been determined. 



In approaching the question we must bear in mind the fact that this 

 iron- bearing formation was probably at one time spread over nearly the 

 entire district with more or less uniformity. Ever since that time, however, 

 it has been subjected to mountain-making forces and active processes of 

 erosion. The few areas of this formation which we now find are only those 

 remnants of it which, being infolded in the underlying formation and 

 thereby to a certain extent protected from erosion, have fortunately 

 remained. 



It has already been stated that most commonly the contacts between 

 the greenstone and the iron formation are wanting. Still a sufficient 

 number of good contacts were found to leave no dou.bt whatever as to the 

 usual relation. Where not wanting the contact is usuall}' exposed only 

 over a very small area; where favorable exposures have been found the 

 usual relations are such as are described in the following paragraphs. 



The jasper of the iron formation occurs in the greenstone in lenses of 

 varying size, ranging from 6 inches in width upward, the smaller ones 

 being very common. The larger ones are rarely exposed over their entire 

 surfaces, and such partial exposures make it ver}^ difficult to trace the 

 various bands through the full length of the lenses, and it is practically 

 impossible to recognize the same bands at different places unless one can 

 trace them over the intervening areas. About a quarter of a mile north of 

 the north shore of Fall Lake, in the NE. ^ of sec. 13, T. 63 N., R. 12 W., 

 the jasper is found in the greenstone in narrow bands, from 4 to 5 inches 

 wide, which are bent sharply upon themselves, showing the extreme fold- 

 ing to which they have been subjected. Similar bands varying in width 

 from a few inches to 2 feet are found in the NE. ^ of sec. 7, T. 63 N., R. 

 11 W., infolded in the amygdaloidal ellipsoidal greenstones, and there form 

 small synclines pitching east. South of Moose Lake, in sec. 4, T. ^3 N., 

 R. 9 W., on the narrow neck of land separating the two small lakes, the 

 infolding of the jasper in the greenstone is well shown. In many excellent 

 exposures it is clear that the jasper overlies the greenstone. One especially 

 good exposure showing this relation very clearly can be seen on the north 

 side of Jasper Lake. Here the iron-bearing formation is in Canadian ter- 

 ritory, but is in direct continuation of and really in connection with the 



