Plate 7 



Photomicrograph of no. Sii. Grenville from east side of quadrangle. Taken with crossed 

 nicols, rnagnification about 30 diameters. 



Showing a typical very complex make-up and comparatively fine grain. 



a Quartz — abundant (clear), b Plagioclase feldspar much less abundant (clear), c Biotite 

 very abundant (gray plates with cleavage) . d Hornblende, abundant (dark) . e Titanite abundant 

 (very rough, small gray grains). /Magnetite (a little) (black), g Apatite (high relief, clear an'i 

 small grains) . 



Plate 8 



Photomicrograph of no. 512. Injection facies of Grenville from east side of quadrangle. 

 Probably a Pochuck injection product. Taken with plain light, magnification about 30 diameters. 



Showing a rather massive type with abnormally high apatite content, a Biotite abundant 

 (dark smooth and in plates), b Hornblende abundant (dark with coarse cleavage), c Apatite 

 abundant (high relief, colorless grains in the hornblende and elsewhere), d Quartz (few clear 

 grains). xe Pyrite (large black grains). / Titanite (very rough), g Magnetite (a little) (black). 



