THE LOWER HURONIAN. 325 



it may be that ore deposits will eventually be found in this area, although 

 it is very doiibtful whether the formation carries ore in paying quantity at 

 any of the places examined. The greater part of the data for the descrip- 

 tion of this formation was obtained from Canadian areas, in which a brief 

 reconnaissance was made and in which this formation is best developed. It 

 derives its name from Agawa Lake, where it is well exposed. 



Distribution. — The iron-bearing formation occurs only in narrow belts 

 which are not continuous for great distances. The westernmost occurrence 

 is on the portage between Wind and Moose lakes," and the exposures here 

 consist of thin bands of iron oxide, chert, and jasper interbanded. The for- 

 mation is again found on Sucker Lake, and extends thence northeastward 

 into Birch and Carp lakes Here it is in character a ferruginous, carbonate- 

 bearing slate. It has been followed into Ontario for about 12 miles in a 

 direction a little north of east through the string of lakes which lie about 

 IJ miles north of the international boundary on Knife Lake, and are 

 known from west to east as That Mans, Agawa, This Mans, and The 

 Other Mans lakes. In this area it is present in very characteristic devel- 

 opment, and consists chiefly of bands of chert, jasper, and iron oxides, with 

 a carbonate-bearing chert and ferruginous slate in very subordinate 

 quantity. The next area in which it is known to occur is on the northeast 

 arm of Ogislike Muncie Lake on both the northwest and southeast shores. 

 Especially on the southeast shore is it well developed. Here it is the 

 carbonate-bearing phase, like that which occurs on Birch and Carp lakes. 



In a traverse made southward from Knife Lake along the section 

 line between sees. 29 and 30, T. 65 N., R. 6 W., at about 200 paces south 

 of the lake shore there is a high ridge of Knife Lake slates and g-ray wackes, 

 and the finer-grained slate grades directly down into banded slate and 

 jasper. Only a short distance south of this occurs the basal greenstone on 

 which rests the slate series. Here jasper bands are interlaminated with the 

 bottom part of the slate series which seems to coi-respond to the iron-bearing 

 formation observed on the ]Moose Lake- Wind Lake portage, and at the other 

 points noted above. It could not be followed to the east and Avest. A similar 

 occurrence of jasper bands in the Knife Lake slates has been noted upon 

 Pickle Lake.'' These occurrences are interesting as showing the existence 



«Geol. and Nat. Hist. Survey cf Minnesota, Final Kept., Vol. IV, 1899, p. 278. 

 6 Grant: Ibid., pp. 440 and 460. 



