44 



The ore is magnetite, rather freely supplied with sulph- 

 ides, chiefly pyrite, but also including traces of chalcopy- 

 rite. It occurs as a series of overlapping lenses, separated 

 from one another by walls of greenstone, and bounded on 

 the north side by a wall of highly sheared acidic rocks. 

 Associated with the ore and interlaminated with it, are 

 beds of greyish-white chert and dark green slate. In 

 places along the strike, especially near the east end, narrow 

 beds of ore, chert and slate may be seen interlaminated 

 with each other. The ore-bodies and associated rocks have 

 a common strike and dip, the later varying from vertical 

 to 6o° north. 



The following account of the origin of the ore-body is 

 given by Dr. Lawson in a forth coming report of the 

 Geolical Survey of Canada, and on account of its dissimi- 

 larity to other interpretations is worthy of quotation 

 almost in toto: 



"Iron ores occur either at the contact or close to it where 

 there is no conglomerate. The ore and the conglomerate 

 thus appear to be in a certain sense complementary features 

 of the base of the Seine series. It is interesting to note 

 in this connection that the pre-Seine surface of the Keewatin 

 greenstones, where it emerges from beneath the Seine 

 series, is commonly heavily charged with carbonates 

 (including siderite or ankerite) and limonite. This 

 condition in some sections obtains for several hundred 

 feet away from the contact, and with little question it 

 represents the effect of the weathering of the Keewatin 

 surface in pre-Seine or early Seine time. It suggests a 

 supply for the iron ore that is found in workable bodies 

 and in less important prospects along the line. The 

 concentration may have been effected in bogs in early 

 Seine time, a possibility which harmonizes with the absence 

 of conglomerate at such points along the contact; or it 

 may have been concentrated by underground circulation 

 after the burial of the weathered and iron-rich surface 

 by the Seine sediments." 



Particular interest attaches to this particular occurrence, 

 because of the successful attempt of the company to use 

 an ore which is not only hard but also markedly rich in 

 sulphides. 



The mine has a good surface equipment, and the company 

 owns an up-to-date blast-furnace at Port Arthur which 

 was designed and erected primarily for the treatment of 



