37i 



Kilometres r °ck surface of the Pre-Cambrian shield. The 

 underlying Ordovician limestone is hidded 

 except at Tyndall and Garson, where quarries 

 may be seen at some distance from the railway. 

 69-5 m. Darwin — Altitude 972 ft. (296-3 m.). From 



101 -8 km. Darwin to Summit, a total distance of 340 

 miles (547 km.), the route crosses a region under- 

 lain by alternating stretches of Keewatin schists 

 and Laurentian granite-gneisses that present 

 no points of particular interest. The solid 

 rocks are covered more heavily than usual 

 with boulder clay and stratified clays, and 

 consequently the topographic relief is even 

 less than in most parts of the Pre-Cambrian 

 shield. Rock-bound lakes are very numerous. 

 132-7 m. Kenora — Altitude 1,088 ft. (331 -6 m.)- The 

 213-5 km. Keewatin-Laurentian contact lies not far to 

 the north of the railway in the vicinity of 

 Keewatin and Kenora. In consequence of 

 this, the Keewatin schists have been contact- 

 metamorphosed into highly crystalline horn- 

 blende schists and gneisses. 



A fine view of Lake of the Woods is obtained 

 just as Kenora is entered. This town, the 

 largest between Winnipeg and Fort William, 

 is the business centre for mining, lumbering 

 and milling industries in the Lake of the Woods 

 district. 



PRE-CAMBRIAN GEOLOGY IN THE NORTHERN 

 PART OF LAKE OF THE WOODS. 



General Geology of the Region. 



The northern part of the Lake of the Woods is 

 characterized by rocky shores, numerous islands and 

 a rugged topography, though the elevation of the 

 highest hills above the level of the lake is seldom more 

 than 150 feet (45 m.). Though most of the islands 

 and the main shore are covered with a dense forest 

 growth, principally of second growth spruce, jack pine 

 (P. banksiana), and birch, there is as a rule not a great 

 depth of soil overlying the rock, which can be seen almost 

 35069— 7B 



