estimate is made by Lawson that the average thickness of the 

 whole Huronian formation may be set down at 23,750 feet, or 

 four and a half miles. 



3. The presence at various points in the Huronian of 

 intrusive granitic rocks is very noticeable and significant. 

 This rock is found at ten main centres through the area of 

 the Lake of the Woods district, such as Rossland station, 

 Yellow Girl Point,, the Northwest Angle, Portage Bay, etc. 



The occurrence of granitic intrusive rocks is of prime 

 importance in considering the bedding of the Huronian for- 

 mation, in finding the direction of metalliferous veins and in 

 dealing with the question of metamorphism. 



SURFACE ACTION. 



The rocks of the Lake of the Woods region would seem 

 to have been always somewhat level in their general outline. 

 There were no precipitous cliffs and great valleys such as are 

 found in mountainous regions. No doubt the soft rocks of 

 the northern section would be much worn away by the de- 

 nuding agencies occurring during the long periods of time 

 which have elapsed since their formation and elevation above 

 the sea. The glacial action is, however, very clearly followed 

 on the surface of the existing rocks. Lawson says : " The 

 Lake of the Woods and surrounding country may be consider- 

 ed essentially as a pai-tially flooded area of ' roches mouton- 

 nees,' " i.e., rounded hummocks and even large islands. The 

 whole country is scraped bare, polished and grooved. The 

 rocks everywhere bear evidence of this general action. Striae 

 showing the direction have been found in upwards of 200 

 locations on the islands and rocky shores of the lakes, and 

 these have a general southwest direction. 



A curious question has arisen as to the origin of certain 

 limestone boulders found along the shores of the Lake of the 

 Woods. No rock of this kind is known east or north of this 

 region, at least on the southern slope. These limestone 

 boulders are a peculiar feature of the south end of the lake. 

 Three different theories have been used to account for this. 



