Miles and 

 Kilometres. 



214 



the 97th mile-post, to the Illecillewaet gorge, 

 a distance of 10 miles (16 km.), the route 

 crosses the northeasterly dipping beds grouped 

 under the name, Laurie formation (See p. 134). 

 Its apparent thickness is extremely great 

 and, as yet, no evidence of large-scale duplica- 

 tion of strata has been discovered. Dawson 

 considered that these beds have a synclinal 

 structure, (G.M. Dawson, Bull. Geol. Soc. 

 America, Vol. 2, 1891, p. 174), but detailed 

 work has shown that they form a monocline 

 accidented by rare, narrow strike-zones of 

 crumpling. The most important of such zones 

 is clearly visible from Laurie station (100 ■ 5 m.) 

 in the long gulch due northwest of that point. 

 Allowing liberally for all such evidences of 

 repetition, the Laurie formation is still to be 

 credited with a minimum thickness of over 

 4,500 metres. 



From Flat creek to Illecillewaet (102 -8 

 mis.; 165-4 km.) the dip averages about 50 

 to the N.E. The dark-gray to black, often 

 highly carbonaceous and pyritous metargillites 

 are well exposed in occasional long railway 

 cuts. They are remarkably homogeneous for 

 a nearly continuous exposure of 500 to 1,000 

 metres at a time. The principal variations 

 consist in the alternation of more massive 

 phases with the dominant fissile metargillite ; 

 rare, thin beds of carbonaceous limestone are 

 found but the quartzitic interbeds noted in 

 the columnar section do not crop out at the 

 railway (see p. 134). Though the metargillite 

 usually has a phyllitic appearance, this is not 

 due to dynamic metamorphism. Schistosity 

 and bedding are almost always parallel, and 

 here as usual in the entire Selkirk series, the 

 recrystallization of the original muds was 

 accomplished under the static condition of 

 deep burial, and before orogenic deformation. 



At Illecillewaet (102-8 mis.) the dip has 

 flattened to io° — 15 N.E., with local crumpling. 

 The dip increases to 25 and then to 40 N.E. at 



