348 



THE AZOIC SYSTEM AKD ITS SUBDIVISIONS. 



distribution of tlie two series can be mapped by means of our present data, it 

 would appear that the various bands of entih set of rocks in contact with each 

 other, correspond in their general run, and partake of the same curves and 

 flexures." {I. c.j p. lOG.) 



Regarding Mr. BelFs observations Mr. Selwyii states : 



" It may, however, be remarked that though the facts observed undoubtedly 

 lead to the conclusion, as stated by Mr. Bell, that the two series are in conf(jrm- 

 able sequence, yet it is far from improbable that this aj)parcnt conJ'ormity is 

 only local, and that the result of a more extended and detailed investigation of 

 the structure would serve to shew that there is in reality a very considerable 

 break and much unconformity between the Laurentian gneiss and the over- 

 lying schistose and slaty strata. As regards the age of these so-called Iluronian 

 rocks, the evidence is not of the most satisfactory kiiul. While stratigi-ap Id- 

 eally they rest directly upon highly crystalline and typical Laurentian gneisses, 

 mineralogically they resemble as closely the chloritic, epidotic and diorilic 

 strata of the altered Quebec group as tkey do those which on the shores of 

 Lakes Huron and Superior are referred to the Iluronian series." (/. c, pp. 

 13, 14.) 



In this connection it is well to remember that these rocks were re- 

 ferred to the Laurentian and Iluronian on the same evidence that four 

 fifths of the rocks so called are, — lithological, namely, —and that the 

 evidence of conformability given by Mr. Loll is just as strong as any of 

 the evidence of unconfurmability ; also, that Logan hud shown that 

 the two formations were conformable. Moreover, it had been shown 

 that the Huronian lay beneath the Laurentian. We do not see that 

 Mr. Sclwyn's statement has any basis of fact, it being decidedly op- 

 posed to all the evidence collected by the Canada Survey. 



In the Eeport for 1872-73 (p. 101), Mr. Ecll states : 



"The junction of the Laurentian rocks on the north with the Iluronian 

 schists of the Lake of the Woods on the south takes place on Kat Portage. 

 The two rocks j,ire seen almost in contact with each other, and have the same 

 strike and dip." 



Mr. George M. Dawson says of the same locality :- 



" The southern end of the path passes over Huronian rocks At 



the water's edge .... they were found to be vertical, with a strike of N. 

 75° E. About half-way across the Tortage, and at its highest, part, the rocks 

 dip N. 17^^ W. < 48°, and are then immediately succeeded by Laurentian 

 gneiss, which is granitoid, and of alight pinkish-grey colour ; dip N. 30^ W. 

 < 89°. The junction is so close that one may actually lay the baud up(jn it, 

 and the separating line is remarkably straiglit and even. Followed about 

 one hundred yards westward, it was ioxmk to preserve the course of S. G7° W,, 



