124 IF. P. Blake — Tourmaline of Grown Point, N. Y. 



planes are bright and flat and the meeting of these six planes 

 gives, as a rule, sharp intersections, the m planes being repre- 

 sented by reflections from striae where they were found at all. 

 On the contrary, the complemeutaiw m planes show in two 

 instances as bright well-defined planes. The large develop- 

 ment of o and u, in figs. 8, 9, and 10 by Farrington, are repre- 

 sented on one fragment of the Crown Point material, but were 

 attributed to accident of growth, and were taken as exceptional 

 in view of their smaller development on the other specimens." 



