THE LOWER HURONIAN. 295 



are still present most perfect examples of false bedding in the normal 

 unmetamorphosed slates. 



These metamorphosed slates consist of green hornblende, actinolite, 

 mica (biotite, mnscovite, and sericite), feldspai', qnartz, chlorite, rutile, 

 epidote, sphene, apatite, calcite, garnet, and iron oxide. In some of these 

 the garnet and inuscovite appear as porphyritic constituents full of inclu- 

 sions of the other minerals of the rock, thus showing that their origin is 

 later than that of these constituents. 



THICKNESS. 



The folding of the slates has resulted in excessive crumpling and a 

 slight overturning with an average dip of about 80° N. That this condition 

 exists is shown by a number of minor anticlines and synclines which have 

 been observed. It is very probable, therefore, that the thickness of the 

 slates has been several times repeated in the area. Bearing the above facts 

 in mind, one will readily appreciate the statement that an estimate based 

 on the width of the slates and the width of the area would probably give a 

 thickness many times too great. As such an estimate would only lead to 

 eiToneous conclusions, and as we have no better means of making a more 

 accurate estimate, no attempt is made to give the thickness. 



INTERESTING LOCALITIES. 



The general characters of the Knife Lake slates occurring in the 

 western part of the Vermilion area can be seen at many places on the 

 islands in Vermilion Lake and on the shores of the lake. The slates are 

 well exposed on the east end of Sucker Point and on the adjacent shores 

 of the mainland, and here one has good opportunities to examine them at 

 localities that are readily accessible. The high hills east and southeast of 

 Swede Bay, in the SE. i of sec. 20, T. 62 N., R. 15 W., afford a number 

 of bare rounded surface exposures of these slates, and here, too, the results 

 of the intricate folding to which they have been subjected can be studied. 

 Similar slates may be observed at several places on the south shore of Ely 

 Island, on Canoe Island, and on the island south of its eastern end, and also 

 on the south shore of Pine Island, as well as at a great many places on the 

 lake. These slates are also exposed on the south slope of Soudan Hill, just 

 above the road, and on the road at the crest of the small hill in the town 



