4 6 



Miles and 

 Kilometres. 



131 -6 m. Hematite — Altitude 1,360 ft. (415 m.) 

 211-9 km. From this point westward to Atikokan, the 

 railway marks approximately the contact of 

 the Seine with the Keewatin group. The 

 latter stands out in much weathered exposures 

 of greenish-coloured schists in the hills just to 

 the north of Atikokan river. To the south 

 and usually in the rock-cuts along the railway 

 may be seen the quartzites and quartz slates 

 of the Seine series. The iron formation of the 

 Atikokan range which outcrops at intervals 

 on both sides of the track is probably an exten- 

 sion of the ore-bodies northeast of Iron Spur. 

 Half-way between mile posts 139 and 140, 

 there seems to be an actual contact between 

 the Seine series and the Keewatin but no trace 

 of a basal conglomerate could be found. With 

 the exception of a short space just east of mile 

 post 141, occupied by Keewatin greenstones, 

 exposures of the Seine series continue more or 

 less intermittently to Atikokan. 

 142-4 m. Atikokan — Altitude 277 ft. (389 m.). From 

 229-5 km. this point a side excursion occupying half a day 

 is taken to Steeprock lake to examine the foss- 

 iliferous limestone and the structural features 

 of the Steeprock sedimentary series of the 

 Archaean. 



GEOLOGY OF THE VICINITY OF STEEPROCK 



LAKE. 



General Description. 



The physiographic features of this region are typical of 

 those in the southern part of the Pre-Cambrian terrane. 

 The rocky lake country, which is here well exemplified, 

 presents the character of a peneplain. Regarded on a 

 large scale, it is remarkably flat and devoid of prominent 

 elevations, but, when considered in detail, the surface 

 is extremely uneven and hummocky. 



The general geology of the region was partially worked 

 out by Dr. Lawson for the Geological Survey in the summer 



