SOUDAN FORMATION. 207 



one-fourth of a mile due north of this locaHty, in sec. 33, T. 64 N., 



R. 9 W., there are some exposures showing very clearly the relations 



which exist between the greenstones, the iron-bearing formation, and the 



sediments that occur in such large quantities in this area south of Moose 



Lake. At this place the greenstones occupy the opposite sides of a 



considerable depression in which occur most commonlj- the exposures of 



the fragmentals. Occasionally an irregular area of the old ellipsoidally 



parted greenstone rises through these fragmental deposits (fig. 4). At 



the place mentioned, a narrow belt of iron formation, about 20 feet in 



length, was observed lying- on the north side of such a small irregular 



area of greenstone. South of this 



there were small, irregular areas of Oglshke co^nglomerate ^ 



iron formation completely surrounded W^ '''^^^,^^o°^^^t3 



by the greenstone. Immediately ad- ^^^^^^^^^^^^^o N 



iacent to the iron formation and the 



greenstone occurs the Ogishke con- < 



glomerate, consisting of fragments of ' 



greenstone with, in the immediate 



vicinity of the jasper, considerable 



numljers of fragments of jasper, show- 



ino- very clearly that it is derived from --z::^ 



the jasper and the greenstone, which ^ ^/ ^ ca e ^ ^^^^ 



are the underlying formations. Fig. ^---^^ ■^^•- ^ -"■ 



Fig. 5.— Sketch showing association and relations of Ely 

 5 is a sketch illustrating the aSSOCia- greenstone, Soudan formation, and Ogishke conglom- 



erate. 



tion of the rocks at this locality. It 

 is very evident that the irregular distribution of the greenstone is due to 

 the intricate folding to which all of the rocks have been exposed, and the 

 subsequent truncation of the folds, whicli has left the outcrops of the forma- 

 tions in their present relations. 



On the Canadian shore of Otter Track Lake, on the Avest side of the 

 strait leading to the north and south arms, and just beyond the main portion 

 of the lake, there is a considerable exposure of iron formation in contact 

 with the old greenstones. The formations are well exposed along the lake 

 shore, being present in cliffs which are about 75 feet high and ver)' nearly 

 perpendicular. The contact between the jasper and the greenstone is 

 very irregular on a large scale, although when examined in detail the line 



