39 

 ANNOTATED GUIDE. 



(Port Arthur to Iron Spur.) 



Miles and 

 Kilometres. 



o-o m. Port Arthur — Altitude 607 ft. (185 m.). 



o-o km. 



3-0 m. Fort William — Altitude 612 ft. (186 m.). 



4-8 km. These two cities, commonly known as the"Twin 

 Cities," are located at the head of the Great 

 Lakes system of navigation. The rocks under- 

 lying Port Arthur and Fort William consist of 

 apparently flat-lying Animikie sediments (slates, 

 indurated shales, cherty dolomites, etc.) and 

 Keewenawan diabase sills. The characteristic 

 topography produced by the erosion of this 

 group of rocks can be seen in the islands and 

 shores of Thunder bay. The flat-topped, steep- 

 sided outlines of these hills are produced by 

 cappings of diabase which have protected from 

 erosion the underlying sediments. In some 

 sections more than one sill may be observed. 



Leaving Port Arthur, the train takes a south- 

 westerly course across the post-glacial flood- 

 plain of the Kaministiquia river to the towns 

 of Fort William and Westfort. A short distance 

 to the south of Westfort, McKay Mountain rises 

 to a height of 1,600 feet (488 m.) above the 

 sea, and exhibits pronounced mesa-like outlines. 

 The horizontal attitude of the sills and Animikie 

 sediments, as well as the vertical columnar 

 jointing of the former, may be readily observed 

 from the train. After passing Westfort, the 

 soft, rounded outlines and roche montonee 

 topography characteristic of the southern part 

 of the Archaean terrane, appear in the far dis- 

 tance to the north and northwest. 



23-4 m. Kakabeka Falls — Altitude 912 ft. (278 m.). 



37-7 km. Up to this point, and for some distance beyond, 

 the railway traverses the flood-plain of the 

 Kaministiquia, and the total absence of rocky 

 hills near at hand is a striking feature . Near 

 the station, however, the Kaministiquia drops 

 a short distance over Archaean granite-gneiss, and 



