45 



the high-sulphur Atikokan ores. Before being smelted 

 these ores are specially treated to eliminate the sulphur, 

 so far, with remarkable results. 



Irruptive Contact of the Algoman Granite with 

 the Seine Sedimentary Series. — The phenomena to be 

 observed in this connection extend from a point on the 

 railway spur one eighth of a mile (o-2 km.) from the main 

 line along the spur to the main line, and then for an eighth 

 of a mile (o-2 km.) westward along the main line. On 

 returning from the iron mine, the following points in 

 connection with the intrusion can be noted in the order 

 given. 



i. Dykes and stringers of granite cut the dark-coloured, 

 anamorphosed phase of the Seine series, and frequently 

 traverse it across the bedding. 



2. Angular to rounded fragments of the altered Seine 

 rocks are abundant within the granite mass. 



3. Assimilation of these inclusions by the intrusive is 

 shown by its abundant content of hornblende and general 

 adoption of a basic phase near the intruded series. 



4. A short distance from the contact, the Seine rocks 

 resemble a dark-coloured gneiss, rich in quartz and biotite 

 with stringers of lighter-coloured, more or less feldspathc 

 material. 



5. The passage from this anamorphosed variety through 

 a less altered one to the normal phase may be well followed 

 by observing the exposures in two railway cuts, about 

 an eighth of a mile (0-2 km.) along the main line and just 

 west of the section house. The character of the anamor- 

 phosed Seine series should be especially noted in order that 

 it may be compared with that of the Coutchiching series 

 in the Rainy Lake area. 



ANNOTATED GUIDE (Iron Spur to Atikokan). 



After leaving Iron Spur occasional exposures of the Seine 

 series, separated by stretches of muskeg occur on both 

 sides of the line. The valley of Atikokan river follows 

 rather closely from the crossing just west of Iron Spur. 



