54 



K&mSSL. a f eW feet SOUth ° f the track ' and the Chief 



points to be noted are: — 



1. The nature of the rocks — phyllitic slates. 



2. The strike and dip of the bedding or 

 cleavage planes. 



3. The reverse or overthrust character of 

 all the faults. 



4. The constancy of direction of the glacial 

 striae, and their extension on both the upthrow 

 and downthrow sides to the very edge of the 

 fault plane. 



5. The sharpness of the fault scarps. 



6. The coincidence of the fault-planes with 

 the cleavage of the slates. 



7. The absence of fault breccia or slickensides. 



8. The absence of any horizontal component 

 in the differential movement. 



9. The number of fault scarps (24 in 66 feet 

 (20 m.) across the strike), and their average 

 height. 



10. The presence of a transverse fault. 



11. The presence of one stepped scarp. 



For reasons explained in his paper (8) 

 Dr Lawson ascribes the faulting not to orogenic 

 forces, but rather to the play of compressional 

 and relaxational forces resulting from change 

 of temperature or load. He cites other examples 

 from geological literature of such faulting, 

 and concludes that it is peculiar to slaty rocks. 



165*0 m. Mayflower. — From a short distance west 

 265 km. of Mayflower to milepost 169, the Seine- Kee- 

 watin unconformity is again south of the railway, 

 and Keewatin rocks are exposed on both sides. 

 For the succeeding eight miles (12 -8 km.) the 

 railway runs in a northwesterly direction and 

 affords a partial section of the Seine series, 

 through the quartzites and slates to the basal 

 conglomerate, which is excellently exposed 

 just west of Mathien. (176 m., 283 km.) 



The remainder of the trip as far as Mine 

 Centre is through a drift-covered area underlain 

 by the Keewatin which outcrops only at inter- 

 vals. 



