PLATE XLIII. 



FIG. 1. 

 FOLIATED GKANITE. 



BfiN VUBOCH. 



Polished surface ; natural size. 



The white len tides are formed of felspar and quartz. Under the microscope 

 the centre of a lenticle is seen, in most cases, to consist of a large irregular 

 grain of felspar showing microcline structure. The marginal portions of a 

 lenticle are formed of felspar or of felspar and quartz in the granulitic condition. 

 The granulitic aggregate often penetrates, traverses, and more or less replaces 

 the large individuals of felspar (see figs. 22 and 23, p. 175). 



The dark bands which sweep round the white lenticles are formed of black 

 and white micas and a granulitic aggregate of quartz and felspar. Garnet is 

 present as an accessory mineral. For a further description of this rock, see 

 page 325. 



FIG. 2. 

 FOLIATED GABBEO. 



KABAKCLEWS. 



Polished surface. Natural size. 



The white patches are formed of alteration products after felspar. The dark 

 coloured knots, lenticles and streaks are composed of diallage and hornblende. 



The two figures on this plate illustrate the fact that precisely similar types 

 of foliation occur in rocks of very different chemical and mineralogical 

 compositions. 



