of the Paleozoic Outlier of Lake Timiskaming. 299 



a straight course parallel to the northwest and southeast 

 system of fracturing suggests the influence of structural 

 relations. Post-glacial faulting along an old fracture 

 line, such as occurred at Cobalt, may have fractured the 

 clay sufficiently to determine the position of the river 

 course. However, as no proof of any movement in the 

 clay could be found, the river may owe its present position 

 to normal development on a gently sloping clay plain. 



During this period of readjustment to isostatic equili- 

 brium, with which post-glacial faulting is probably con- 

 nected, there seems to have been a regional tilting to the 

 south in this district. As has already been stated, the 

 more northerly beaches are at a slightly higher elevation 

 than those farther south. Also clay deposits are known 

 in the vicinity of the Continental Divide at an elevation of 

 about 1100 feet (Wilson 1918), while at Haileybury the 

 highest reported occurrence is at an elevation of 775 feet 

 (Coleman 1909). This represents a slope of approxi- 

 mately 5 feet per mile. The slope of the country from 

 Englehart along the Blanche river to the north end of 

 Lake Timiskaming is of the same order of magnitude. 

 This does not mean a tilting of 5 feet per mile, because 

 undoubtedly part of this was original slope, and until fur- 

 ther detailed leveling work is done the amount of tilting 

 can not be definitely stated. 



Relation of Physiography to Structure. 



Over deepening of the Timiskaming trench. — A study of 

 the regional map reveals that at about the mouth of the 

 Montreal river there is an intersection of the three frac- 

 ture systems. The great northwest and southeast line is 

 represented by the straight course of the Montreal river, 

 the northeast and southwest system by a line through the 

 Matabitchuan river and a number of lakes to the south- 

 east, and the north and south system by the straight north 

 and south portion of Lake Timiskaming for 10 miles north 

 of the mouth of the Montreal river. This point of inter- 

 section must therefore be a much disturbed and fractured 

 part of the Timiskaming drainage system. Below the 

 mouth of the Montreal river, soundings made in the lake 

 show a maximum depth of 470 feet or an elevation for the 

 bottom of the lake about 110 feet above sea level. The 

 outlet at Mountain rapids has an elevation of about 415 

 feet, so that the portion of the lake south of the Montreal 



