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18 College of Forestry 
Original by Richardson 
FicurE 6. 1. Composed of three sets of pinacoidal planes. 2. Com- 
posed of the same three sets of pinacoidal planes but modified by an 
orthodome. 3. The face of a prismatic form where the inclination of 
the clino axis is less than one degree. 4. Twin crystals where the 
twinning place is the ortho axis. 5. Composed of two sets of pina- 
coidal planes and two ortho domes. 6. A prismatic form terminated 
at either extremity by a pyramid. 7. A prismatic form terminated by 
a basal pinacoid, two clino domes and an ortho dome. C. H. Richardson. 
Ez 
