• ) 



18 A. E. BARLOW — LAURENTIAN AND HURONIAN ROCKS. 



being seen embedded in a matrix composed of feldspar, quartz, and mica. 

 Feldspar is by far the most abundant constituent, and tbe foliation, which 

 is quite distinct, consists chiefly of a parallel arrangement of the feldspar 

 crystals. Embedded in the gneiss are patches and strips of highly 

 altered quartzite, plainly referable to the Huronian quartzite in the imme- 

 diate vicinity and corresponding in strike with the foliation of the en- 

 closing rock. 



TRANSITIONAL ROCK-MASSES BETWEEN THREE-MILE AND BRUSH CAMP LAKES. 



To the northeast of Three-mile lake, and also between this and Brush 

 Cam}) lake, there appears the interesting phenomenon of a sort of transi- 

 tion from one formation to the other. At these places a band of gneissic 

 quartzite occurs which may be due to the fusion of the two rocks in situ 

 and the absorption or passage of the components of one rock-mass into 

 the other. Both rocks incline to the southeast, the quartzite dipping 

 into or under the gneiss. 



THE CONTACT ON BRUSH CAMP LAKE. 



On Brush Camp lake the immediate contact was seen at three places, 

 the two rocks in these cases holding the same position as on Three mile 

 lake, but the line of division is sharp and distinct. At one point on the 

 north shore a boss of coarse red gneiss was seen protruding through and 

 disturbing the quartzite, the strike of the latter curving round so as to 

 conform with its outline. 



THE QUARTZITE AND GNEISS OF CROOKED AND JOHNNY LAKES. 



On Crooked lake it was observed that four irregularly-shaped patches 

 of quartzite had been apparently caught up in the gneiss, the contrast 

 in color between the two being very marked. The largest one of these 

 on the west shore was triangular in outline, measuring about a quarter 

 of a mile in length. A mass of the same white quartzite was also noticed 

 embedded in the gneiss on a small island in Johnny lake, nearly one 

 mile and a half from the line of junction. 



GOSCHEX TOWNSHIP A XI) LAKE PANACHE. 



Direction and Extent of the Contact. — From the eastern boundary of the 

 township of ( roschen thelineof division turns in the direction of X. 20° E. 

 for about four miles, passing Lake Panache about a mile to the east. 



Quartzite <in<l its microscopic Examination. — The shores and islands of 

 the eastern portion of Lake Panache are occupied by a granular quartzite 

 of varying shades of gray. Mica in the form of minute disseminated 



