174 



G. M. DAWSON — STRUCTURE OF THE SELKIRK RAXGE. 



plish, slightly opalescent quartz occurring in the con- 

 glomerates and quartzites of the Cambrian seems "pfudc 

 undoubtedly to have been derived from the denuda- 

 tion of these very granitic veins. 



Newer Bocks. — On the eastern side of the Selkirk 

 range certain rocks occur which are supposed to be 

 equivalent to the G^ra^^o^i^e-bearing shales and Haly- 

 sites beds of the adjacent Kocky Mountains. As, 

 however, the reference of these beds must as yet be 

 considered doubtful, on account both of the absence 

 of fossils and of the unusually disturbed character "^^^ 

 of this part of the section, nothing more need here '^C 

 be said respecting them. 



The Devono-Carboniferous, Carboniferous, Triassic 

 and Cretaceous strata entering into the composition 

 of neighboring parts of the Rocky Mountains are jnmms 

 nowhere seen in this part of the Selkirks. 



Structure. 



Respecting the~structural features of the section 

 as a whole, little need be added, as, in so for as these 

 may be considered to have been determined, they 

 are rather simple. The western part of the Selkirk 

 range, for a width of about seventeen miles, is essen- 

 tially composed of Archean and granitic rocks, which, 

 it may be added, are continued to the west of this 

 part of the Selkirks across the Columbia range for a 

 further distance of about forty miles. These rocks 

 often lie at low, undulating angles, though they are 

 occasionally much contorted. Above these, to the 

 eastward, is the lower member of the Cambrian which 

 has been referred to as the Nisconlith series. This 

 forms a synclinal, of which the western side lies at 

 a low angle, while the eastern side is steep, the axis 

 being found near lUecillewaet station. To the east 

 of the synclinal is a rather sharp anticlinal, the 

 summit of the dark-colored beds of the Niscoulith 

 series passing out of sight on the eastern side of this 

 fold near the 413th mile-post on the railway. 



The next great synclinal, which coincides with the 

 highest parts of the range, appears to have a trans- < 

 verse width of about thirteen miles. The rocks con- 



