138 THE VERMILION IRON-BEARING DISTRICT. 



The mashing of the Ely greenstone has resuhed in producing very com- 

 monly an imperfect schistose structure in the rocks composing it. In 

 exceptional cases and locally this development of schistosity has advanced 

 to such a point that the rocks have become completely schistose, and even 

 finely fissile. Gradations from the massive, coarse-grained g-reenstones to 

 green schists of dynamic origin have been observed in a number of places. 

 This schistose structure has, however, certainly not reached such universal 

 development that one would be warranted in speaking of the Ely green- 

 stone as a green schist complex. 



Finally, there occurs in a number of places with the rocks described a 

 conglomerate or tuff, whose structural relations to the greenstones are 

 somewhat doubtful. This facies is foimd commonly in small and isolated 

 exposures or under other conditions that preclude the determination of 

 its relationship to the nearest greenstones. These rocks consist of more 

 or less rounded but ii-regularly shaped fi'agments of greenstones of 

 various kinds, but corresponding to those that occur all around them 

 in the district. One can not say, however, that these deposits consist 

 chiefly of fragments of greenstones like those that are nearest them. No 

 definite indications of bedding have in any case been found, nor do the 

 rocks occur in connection with any sediments of which they can be the basal 

 conglomerates. In some places they lie between exposures of the massive 

 greenstone, and one is inclined to interpret such a field relationship as due 

 to alternation of flows and tuff deposits. On the other hand,, however, one 

 may readily interpret this relation as due to infolding of the elastics in the 

 greenstones. Rocks very similar to these, but showing the transition to 

 finer-grained, clearly sedimentairy deposits have been foinid in several 

 places, and are described Avith the Soudan formation, to which they 

 belong. The latter deposits clearly owe their field relationship to infolding 

 within the greenstones. It is highly probable that most, if not all, 

 of these conglomeratic rocks should be so classed. However, a few cases, 

 which will be mentioned under the heading " Interesting localities," have 

 been doubtfully referred as tuffs to the Ely greenstone. These elastics 

 have nothing to do with those belonging to the Ogishke conglomerate, 

 which will be subsequently considered. 



In numerous places the altered greenstones have been more or less 

 thoroughly discolored and impregnated with iron. This impregnation is, in 



