No. 2385. CRY ST ALLOC RAPHIC STUDY OF DATOLITE— SHANNON. 535 



Dividing at and considering the last part: 



3v. 



Dividing at 1 



v 



4v... 

 N,... 



1/15 1/3 1 00 

 1/5 1 3 00 



Zone No. 10. — Pyramid zone. 

 (100) : (021) : (100). Symbol ^. ~ =2. 



Form... 

 Symbol. 



f a 

 \ 100 







121 



1 



s 



[021] 



2.10.5 

 2/5 



_I 



142 

 1/2 



J 



263 



2/3 



B 

 121 



3+2 

 3/2 



100 



Dividing at and considering the second part: 



2/5 1/2 2/3 1 3/2 00. 

 Dividing at 1 : 



v 

 iV... 



2/5 1/2 

 2/3 1 



2/3 

 2 



1/3 1/2 2 /3 1 3/2 2 3 . co 



The zone thus dissected is shown to be normal. It contains the 

 unusual new form 2.10.5. 



Zone No. 11. — Oblique pyramid zone. 



(110) : (012) : (110). Symbol y 



Form... 

 Symbol. 



102 

 



110 



Reversing: 



2v. 



1/4 1/3 3/8 2/5 3/7 1/2 3/4 1 cc 

 1/2 2/3 3/4 4/5 6/7 1 3/2 2 00 



Dividing at 1 : 







1/2 2/3 3/4 4/5 6/7 1 







2 



v 

 T^v 



v',2 12 1 3/2 



N 3 l/3 1/2 2,3 1 3/2 



Zone No. 12 .—Positive pyramid zone. 

 (101): (010). Symbol j- y=Z. 



Form . . . 



Symbol . 



»-l 



2v 



JVi 



101 

 



n 



111 

 1 

 

 



1/3 



a 



454 343 



5/4 ' 4/3 



1/4 ! 1/3 



1/2 2/3 



1/2 2/3is;s 







121 

 2 

 1 

 2 

 2 3 



6 

 010 



This zone, though incomplete, is normal with no extra forms. 



