i6 



through the more or less gneissic varieties, to thinly 

 foliated gneisses. It is impossible to separate the several 

 varieties. They constitute progressive developments of 

 one and the same structure, and are different phases of 

 one and the same rock mass. 



The granite-gneiss is undoubtedly of igneous origin, 

 is very uniform in its mineralogical composition, and differs 

 distinctly from the sedimentary gneisses (paragneisses) of 

 the area. It is medium to rather fine in grain, and com- 

 posed almost entirely of quartz and feldspar, the latter 

 preponderating. Biotite is present in very subordinate 

 amount. The rock in the southern batholiths occasionally 

 contains a little hornblende. While the feldspar is always 

 reddish in colour, a large proportion of it is really an acid 

 oligoclase. The rock would ordinarily be classed as an 

 albite-granite or granite-gneiss, and, although the soda 

 feldspar preponderates, should be so classed, since it 

 resembles a granite in every respect. 



Two analyses of typical specimens of this granite are 

 tabulated below: — 



— 



I. 



Per cent. 



II. 



Per cent. 



Si0 2 



73-33 

 0-1? 



13-55 

 0-58 



i-53 

 0-04 

 166 



o-45 

 3-12 

 5-oi 



o-45 



76-99 



T1O2 



AI2O3 



12-45 

 1-03 

 0-49 



Fe203 



Feo 



MnO.. . 



tr. 



CaO 



0-98 



MgO 



0-21 



K 2 0... . 



4-29 



Na 2 0.. 



3-46 



CO 



None. 



H.O.. 



0-26 





Totals 







99-89 



100-16 



I. Gneiss, Township of Methuen, Lot 17, Range V. 



(M. F. Connor, analyst.) 



II. Gneiss, Township of Livingstone, Lot 10, Range V. 



(N. Norton-Evans, analyst.) 



