182 E. S. Dana—Spodumene from North Carolina. 
ward toward the edge behind in the simple erystals. The 
form of these depressions is more exactly shown in fig. 10, 
representing two in symmetrical position and muc 
enlarged. The lower surface is formed by the plane 
f, and the sides by the planes a, 8,7. Of these 
lanes 7 is apparently identical with g (681), al- 
though, as indicated, it is irregular in its intersection 
with the prismatic plane being curved; ais a plane 
in the prismatic zone, with a~ J=5°, corresponding 
to the plane ¢§ or (650) for which the required 
angle is 5° 13’. The third plane # is in the zone 
, Js T, P, ete., or that of the unit pyramids. The measured 
: e 
and the outlines are respectively parallel to the prismatic edge, 
_ 
