Plate 6 



Upper figure. Palimpsest structure in pegmatitized Grenville gneiss. 

 Biotite is oriented parallel to banding, quartz and feldspar of pegmatite 

 veins at right angles. Locality n.w. of Lake Bonaparte. Natural size. 



Lower figure. Same specimen as above, etched with HF and H2SO4 

 and coated with NH4CI. Shows orientation of pegmatite minerals at 

 right angles to banding. 



