i_-^ L ^— 1 ^ 



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L- r.- --j- 



j - ■■ ^ ^^ J 



^1— .-Ej — •^^- -•••Jtn.r.-j'r — ^v 



346 



THE AZOIC SYSTEM AND ITS SUBDIVISIONS. 



of thcRe. It is remarkable that the greenstone found associated with it is also 

 basaltic, and this is also the case with the trap occurring at the junction of the 

 two formations in the northeast corner of Bachewahnung Bay. Here it is 

 finer grained, but still possesses the glittering fracture of basaltic greenstone. 

 The Laurentian rock is a highly granitic gneiss, and pieced of it arc encdosed in 

 the black greenstone, which at one place seems to underlie the granite. A red- 

 dish-grey ielsitic rock, with conchoidal fracture, is observed at the point of 

 junction. Eastward from it banded traps occur, striking N. 55° W., together 

 with greenstone breccia and conglomerate of the characters already described. 

 On ascending the hills behind this point a breccia is observed, of which the ma- 

 trix is greenstone, and the fi-agments granite. The lines of junction betM'een the 

 Laurentian and ITuronian series, and between these and the U])per Copper- 

 bearing rocks, so far as observed during the exploration, are given on the 

 accompanying map. With regard to the succession of the strata, I found my- 

 self as much at a loss an)oiig the irregularly schistose Huronian greenstones, as 

 among the gneissoid granites of the Laurentian." 



It seems almost incredible that a geologist, who professed to be a 

 lithologist, should have been unable to ascertain the relations and rela- 

 tive ago of these rocks, when so many excellent exposures were observed 

 as he states. His observations show clearly that both formations hero 

 are eruptive, and of the same geological age. 



In the Esquisse Geologiqite da Canada (Paris Exhibition of 18G7, 

 p. 10) the Huronian is said by Br. Hunt to repose unconformably on 

 the Lower Laurentian formation, and probably also on the Upper 

 Laurentian. It is to be remembered, however, that at the locality on 

 the Kaministiquia lUver, in which the Huronian had been seen in con- 

 tact with the Laurentian, the two were found to be conformable. (Ge- 

 ology of Canada, 1863, pp. 64, 65.) 



In the same paper (p. 5) Dr. Hunt claimed that the Laurentian com- 

 prised two distinct series of rocks, of which (me reposed with discordant 

 stratification on the other : these he calls the Lower Laurentian and 

 Upper Laurentian, or Labradorian, 



In the Eeport of Progress for 1866-69, Mr. James Pichardson re- 

 ports, that in the region north of the lower St. Lawrence River 



*' the Laurentian gneiss sometimes has little appearance of stratification ; the 

 strike is generally north and south, with dips often ap])roacliing vertical. The 

 strata are all more or less broken, contorted and faulted. The labradorite 

 rocks rest unconformably on the Laurentian ; they generally strike nearly east 

 and west, and dip at comparatively moderate angles, with little or no appear- 

 ance of contortion or disturbance. .... The reddisli quartzose granitoid rock 

 of the Laurentian is again met with, otFering no evidence of stratification ; and 

 in one place is seen to be distinctly overlaid by a patch, only a few yards 



