WARREN. — ALKALI-GRANITES AND PORPHYRIES. 



235 



10. Fine-granite, South of Ruggles Creek, Quincy. 



4. Average of three analyses of coarse Quincy Granite. 



11. Fine-grained or Micro-granite — ^ Neponset Valley, Mass., F. Bascom, 

 Op. cit., p. 137, Intermediate in the field between the granite (No. 9) and the 

 Aporhyolite (No. 12). 



12. Aporhyolite. F. Bascom, Op. cit., p. 138, Peripheral phase of granite 

 batholith, Neponset Valley. 



The "norm" calculated from the above molecular ratios is as 

 follows : — 



Norm. 



Quartz 24.06 



Zircon . 10 



Orthoclase 29.47 



Albite 37.73 



|^=1.14>f; Class I. 

 91 .36 Salic Minerals. 



^ =.35 < I > 7; Order 4; quardofelic. 



