No. 2385. CRY ST ALLOGRAPH IG STUDY OF D AT OLITE— SHANNON. 513 



yt (T26) . A form near (126) was found on crystal B5 as a very narrow 

 face beveling the angle between g (012) and X (Tl3). The signal was 

 distinct although too faint to illumine the crosshairs. The angles are 

 as follows: 



(T26) Measured <? = 36° 27' p = 26° 58' 



Calculated <p = 38° 02' p = 28° 10' 



A = 1° 35' A = 1° 12' 



r (T32) occurred as a very narrow line face, with (142) on crystal 

 10 between M (122) and & (010), as shown in figure 19. The signal 

 was very faint and could not be accurately centered. The angles are: 



(T32) Measured <? = 25° 49' p = 66°31' 



Calculated ^ = 27° 40' p = 67° 59' 



A = 1° 51' A= 1° 28' 



d (T35), which was described as new from this locality by Unge- 

 mach, occurred on six of the crystals examined. It forms a small 

 face between a (T24) and m^ (011), as shown in figures 9, 10, 16, etc. 

 The faces are usually slightly etched, but give good signals. Angles: 



(T35) Measured, maximum- ^ = 27° 44' p = 40° 53' 



Measured, minimum <p = 26° 49' p = 40° 08' 



Measured, average ^ = 27° 16' p = 40° 30' 



Calculated <? = 27°34' p = 40° 35' 



A= 0° 18' A= 0° 05' 



E (T38) was doubtfully identified as a very narrow and partly 

 etched face between g (012) and X (Tl3) on crystal B5, as shown in 

 figure 13. The signal was too faint for accurate measurement. The 

 angles are: 



(138) Measured <p = 29°44' p = 30° 32' 



Calculated^ = 27° 31' p = 31° 2T 



A= 2° 13 r A= 0° 55' 



<■' (T48) was described as new by Whitlock, together with X' (149) 

 and m' (T.4.10). All three of these forms occur occasionally as very 

 narrow faces, which are either too narrow to yield distinct signals or 

 are on such very large crystals that their measurement is almost 

 impossible. 



p, (227) was observed once as a very narrow line on crystal B2. 

 Angles : 



(227) Measured *> = 57° 56' p = 33°33 / 



Calculated <p = 57° 30' p = 33° 56' 



A= 0°26 / A= o 23' 



27177— 21— Proc.N.M. vol.59 33 



