KETTLE RIVER SECTION 353 



rocks themselves are that there is a large area of graphitic shales. The 

 percentage of carbon in these shales has not yet been determined. 



The graphitic shales disappear, and at the first exposure southward 

 the normal gray glossy schists come into view. There is some variation 

 in the hardness and mineral proportion of the schists. The structure in 

 places is somewhat massive, elsewhere decidedly schistose. The strike 

 is north 60 degrees to 75 degrees east, with a southeasterly dip of 20 to 

 30 degrees, with local measurements as low as 15 degrees. Some little 

 contortion is also seen. 



In section 9, township 45, range 20, there are some interesting nodules. 

 They are more crystalline than those around Mahtowa and at Thomson, 

 approaching more nearly those seen at Little Falls and Moose lake. 



The Kettle River section gives the most satisfactory place for securing 

 an idea of the thickness of the formation that the entire region affords. 

 The northernmost exposure along this stream lies in the northern part 

 of section 16, township 46, range 20, and the southernmost, seen before 

 the northward dipping schists are reached, lies in section 9, township 45, 

 range 20. In this distance of nearly 6 miles, dip was measured at many 

 places. Nowhere was it less than 15 degrees, and at several outcrops it 

 was 30 degrees and more. In the entire distance there was seen no trace 

 of displacement. The average attitude, therefore, can not give less than 

 2,500 feet per mile, which will thus make a total of 15,000 feet as the 

 thickness of the schists of the Kettle River valley. This, it must be re- 

 membered, is without the top or the bottom of the series being seen. 



The foregoing does not include the exposures from Stony brook south- 

 ward to the Blackhoof valley. In this area a folding can easily be 

 traced beneath the more prominent slaty cleavage. Owing to this, any 

 measure of thickness is well-nigh impossible. A conservative estimate 

 of the rocks in sight, taking into account folding, horizontal position, 

 crushing, and other attitudes, is 5,000 feet. Added to the thickness seen 

 in the successive exposures along the Kettle river, Avhich, according to 

 strike measured scores of times, are a continuation of the schists disap- 

 pearing beneath the drift in the Blackhoof River valley, this gives a 

 total of 20,000 feet as a conservative estimate of the thickness of the 

 series under consideration. Farther westward, as has been shown, alter- 

 ation, folding, and eruptive displacement preclude all possibility of 

 reliable estimate. 



Region west of Sturgeon Lake 



At this point there is seen a decided change in the attitude and char- 

 acter of the rocks. The structure becomes sharply crystalline and in 



