468 
MEASUREMENTS OF CRYSTALS. 
CALCAREOUS SPAR. (Continued.) 
c on g . 1 1 55" 
c ono . 90 0 
h on h' ... 92 12 
m on m' . 114 19 
Fig. 76 is a twin crystal from Martins- 
burgh, Lewis county, and Haver- 
straw, Rockland. 
CALCAREOUS SPAR. 
Fig. 79 is a twin from Patterson, Putnam 
county. Face of composition per¬ 
pendicular to the axis of the aggre¬ 
gated crystals : angle of revolution 
60°. 
