R. A. Daly. Amphiboles and Pyroxenes. 



0'^ 10° 20° oO° 40^ 50-" (i()^ 70° 80° 'J0° 



2 I' = 90 



2 1' = 80 



2 V = 70^ 



2V= eo-^ 



2 V = 50^ 



0" 10' 20" oO° 40° 60° 50° 70° 80° 90' 



T-7TTT— r-rn-rrrTT-i 



Plate III. — Showing curves formed on the same plan as those of Plate I. 

 The extinction on (010) is here 20°. 



