308 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



h. In the discussion of the foregoing zones the Bravais symbols have 

 been employed for the obvious reason that they express most clearly 

 the relations of the forms to the zones discussed. In considering the 

 scalenohedral forms, however, the zonal and serial relations are much 

 better emphasized by the Miller symbols, which furthermore are 

 more rational for the more prominent zone intersections. The Miller 

 symbols have consequently been adopted for the subsequent analysis. 



Zone 4 — Scalenohedrons of the Zone [0112 : 1011] = [110 : 100] 



c ^ 



SYMBOL T m 



k 



In this portion of the principal zone a great number of scalenohe- 

 drons have been observed in the comparatively small arc comprised 

 between the limiting poles. Prominent zone intersections occur at 

 (1122) = (210) and (2134) = (310). Splitting the zone at these poles 

 we have for the forms in the first fragment : 



210 

 2 



Referred to X 3 this zone fragment is incomplete and contains the 

 extra forms | and y- 



