PLATE VII. 





i 



^■3 



"'^Si' 



a. Brookfield diorite near center of tunnel showing texture of crystalli- 

 zation. (H) hornblende; (B) biotite; (P) plagioclase (mostly 

 andesine). Plane polarized light x 40. 



b. Biotite hornblendite near center of tunnel showing texture of crys- 

 tallization. (H) hornblende; (B) biotite; (T) colorless amphibole 

 grading into the hornblende. Plane polarized light x 40. 



