376 A. WTNCHELL — RESULTS "l A.RCHEAN STUDIES. 



Similarly, Dr. Lawson observi - 



■ In some of these lenses the interfusion of matrix and inclusion has been so com- 

 plete that they are entirely made up of this transitional rock, which has the facies of 

 b syenite 



Describing the rocks of the Lake of the Woods, he says 



•• It is >i"t uncommon to And in these mica schists a small proportion of feldspar, 

 which gives them the character of finely laminated gneisses, in pla< 



Referring to the north shore of Vermilion lake, State Geologist X. H. 

 Winchell saj - : 



"This schist has a very evident sedimentary structure. It i- firm and even shows 

 an approximation to gneiss, the foliation of which is then the same as the bedding 

 structure <>t' the schist. When, however, the gneissic structure comes on, the grains 

 arc finer than in the schist, the color is darker, but the striping due t<> sedimentation 



i- -till preserved. 



I quote again from Dr. Lawson : 



•■ < >n the Bouth shore of Rainy lake, near « 'outchiching rapids, there i< in association 

 with the mica Bchists an iron-gray micaceous gneiss, differing from the former only in 

 tne possession "fa feldspathic constituent. It might, perhaps, he rather called a feld- 



spatbic mica schist than a L;'nei-- 



"The rocks of the Rice Hay Area [Rainy lake] of the Coutchiching series [mica 

 schists] differ somewhat from those of the same series farther Bouth. They are. as 

 before, all very quartzose and fall into two varieties, those containing feldspar and 

 those free from it. * * * En the feldspathic variety * * * the rock assumes 

 the form of a gneiss of peculiar character. * * In the-.- trthoclase occurs 



sometimes in large crystals from half to an inch aero--. * * There i- a con- 



siderable proportion of feldspar associated with the quartz throughout tin' rock. The 

 schists or gneisses, in which the augen-like feldspars were observed, are is proximity 

 to the very coarse mica-syenite or syenite gneiss on the south side of Bopkins bay, 

 which appears to be of irruptive origin. "2 



This same rock, so gneiss-like thai Dr. Lawson scarcely know- whether to 

 call it gneiss or schist, is described on the following page a- "an eminently 

 granulitic aggregate. The granulitic or roundel character of the 



grains i-, however, characteristic only of the quartz and orthoclase, while the 

 plagioclase often presents irregular or granular shapes." 



From an island in Rainy river he describes a rock which " has tin- aspect 

 ..I' a very fine-grained gray L r nei-> of even lamination. but is found 



to be made up wholly of quartz with a little plagioclase. The 



rounded Bhape of the constituent grains of quartz appears to he due to water- 

 wearing action in an original .-an<l.'"j 



i 



Ibid., p. He, 



Ibid , i' 1 1 1 1 ' lorn pel ■■ duo pp UO i > ■ 



