634 ALFRED W. G. WILSON 



The best known, broadest, and deepest of these is the gorge of 

 the Saguenay, a true fiord. 



From the vicinity of Quebec westward to Lake Superior, and 

 thence northward via Lake Winnipeg, Lake Athabasca, and 

 Great Slave Lake, the convex margin of the peneplain is bordered 

 by ancient sediments. Paleozoic for the most part ; but in th^ 

 extreme northwest Cretaceous deposits are found resting upon its 

 surface. The inner or concave side of the peneplain to the south 

 and west of James Bay, and extending as far north as Fort 

 Churchill, is bounded by a narrow belt of Paleozoic sediments. 

 North of Fort Churchill the ancient peneplain merges gradually 

 with the modern coastal plain of Hudson Bay. The northern 

 end of the western arm of the plain probably passes beneath 

 Paleozoic sediments known to occur north of the Arctic circle. 

 The surface of the peneplain north of the main divide and south 

 of the lower waters of the Albany River and of James Bay, 

 particularly that portion drained by the Moose River system, 

 is almost completely buried beneath clays and sands, chiefly of 

 glacial origin. 



The divide on that part of the ancient peneplain south of 

 James Bay lies nearly midway between the northern and southern 

 boundaries of the plain, north of the city of Ottawa. From the 

 vicinity of Lake Abitibi it runs westerly toward the most 

 northern point of Lake Superior, so that in the longitude of 

 Schreiber station, on the main line of the Canadian Pacific Rail- 

 way, it lies not more than twenty-five miles north of the lake. 

 From here it swings to the northwest, passing to the north of 

 Lake Nipigon, and thence turns southwest toward Savanne on 

 the Canadian Pacific, and continues southward, crossing the 

 international boundary. A portion of the Archaean region lies 

 to the south of the boundary in the states of Michigan and 

 Minnesota, and portions of this area drain into Lake Superior. 

 Following along the line of the western margin of the peneplain, 

 however, from the international boundary as far north as Methy 

 portage (lat. 56° 40' N. ; long. 109° 55' W.) the main divide 

 lies west of the peneplain and at the summit of the Rocky 

 Mountain range. A subdivide, a little to the east of Lake Win- 



