Section III., 1904 [ S7 ] Trans. R. S. C 



y 



X. — An Examination of Some Canadian Micas. 

 By J. E. Eglesox, B.Sc. 



(Presented by Dr. B. J. Harrington, and read June 23, 1904.) 



Hitherto very little work has been done in the chemical examina- 

 tion of Canadian micas, and it is hoped that the following series of 

 analyses may prove of interest and value. Complete analyses have been 

 made of six samp'les, dhosen by Dr. Harrington so as to illustrate differ- 

 enjt modes of oocurrence. iTihe muscovites are from, coarse pegmatite 

 veins, the biotites and phlogopite from apatite-bearing veins, some of 

 which are now being worked chiefly on account of the mica which they 

 contain, while the lepidomelane is an example of a mica occurring in 

 nepheline syenite. 



Localities, etc. 



1. Villeneuve Mica IMine, Ottawa County, Quebec. Muscovite. 

 Colour grayish, pale green by transmitted light. Large axial angle 

 and optic axial plane normal to the plane of symmetry. 

 II, Brassard Township, Berthier County, Quebec. Muscovite. 

 Colour rather dark gray, with a brownish tinge by reflected light 

 and greenish by transmitted light. Large axial angle. First 

 order. 



III. Sebastopol (Range X., Lot 31), Renfrew County, Ontario. 

 Biotite. Colour black and lustre splendent. Transparent only 

 in very thin plates. Axial angle small. Second order. 



lY. McFarlane Apatite Mine, Wakefield, Ottawa County, Quebec. 

 Biotite. Colour brownish black ; more transparent than No. III. 

 Small axial angle. Second order. 

 y. Adams Mine, Portland Township, Ottawa County, Quebec. 

 Phlogopite. Colour light brown, both by reflected and trans- 

 mitted light. Slightly clouded even in very thin plates; this 

 is possibly due to incipient decomposition. Small axial angle. 

 Second order. 



VI. Monmouth Township (Range IX., Lot 16), Ontario. Lepi- 

 domelane. A very black, brittle mica, with small axial angle and 

 high specific gravity. 



