262 THE VERMILION IKON-BEARING DISTRICT. 



FOLDING. 



If the granite lias been subjected to severe mountain-making processes, 

 as it presumably has, it does not now show any very marked effects of 

 these. No folding, of course, could be traced in such a homogeneous rock, 

 and it is only natural that one should find an occasional shearing plane along 

 which the granite is more or less schistose. In general the granite, as 

 already stated, possesses a very massive character. Unquestionably these 

 rocks must have taken part in the folding of the district, but the presump- 

 tion is that in general this great g'rauite mass bordering the north side of 

 the Vermilion district acted as a relatively unyielding area against which 

 the rocks to the south have been forced. As a result partially of this, the 

 adjacent greenstones, consisting primarily to a large extent of easily 

 alterable pyroxene, have been metamorphosed into amphibolitic schists. 



INTERESTING LOCALITIES. 



In the following paragraphs will be found brief descriptions of some 

 localities which show the relations of the granite of Trout, Basswood, and 

 Burntside lakes to the Ely greenstone. 



The relations between these rocks are very clearly shown at many 

 places along the north and west shores of the northwest end of Pine Island 

 and on the adjacent shore of the mainland, where granite dikes intrude the 

 greenstone. These dikes are scattered over a wide zone along the contact 

 between these two igneous rocks, and as a result of their intrusion the 

 greenstone has been altered to amphibolitic schists. The dikes frequently 

 contain large masses and smaller fragments of schists similar to those 

 surrounding them. About 2 miles northeast of Mud Creek Bay and about 

 three-fourths of a mile due north of the Sheridan mine, the schist is intri- 

 cately intruded by the granite. The schist has been so broken up as the 

 result of the intrusion that in places there has been formed almost an eruptive 

 breccia, with the granite as the cementing material. In some cases the 

 intrusive granite assumes roundish forms, and wliei'e the schist predominates 

 one might almost consider the rock a pseudo-conglomerate with granite 

 bowlders in a green schist matrix. 



The relationship between the granite of Burntside Lake and the 

 ellipsoidal greenstones is well shown at a great number of places on the 

 shores of Burntside Lake. Coasting along' the southern shore to the west 



