32 



NEW YORK STATE MUSEUM 



27 Calcite from Union Springs, showing crystal of the first genera- 

 tion, transitional in habit between the pyramid-scalenohedral 

 type [Fig. 23], and the rhombohedral type [fig. 28]. Forms: 

 m (1010), o (1120), y (8.8.16.3), r (1011), M (4041), e (0112), C 

 (6178), X (81. 41. 122. 40). 



28 Calcite from Union Springs, showing crystal of the first genera- 

 tion of rhombohedral habit. Forms: a (1120), y (8.8.16.3), 

 r (1011), M (4041), e (0112), X (81. 41. 122. 40), S' (19. 10.29.6). 



29 Calcite from Union Springs, showing milky crystal of the second 

 generation twinned parallel to c. Forms: a (112 o), r (1011), 

 M (4041). 



30 Calcite from Union Springs, showing the prevailing type of 

 scalenohedral twin of the second generation. This combina- 

 tion is drawn with the twinning plane e (o 1 1 2) vertical. Forms : 

 m (ioio), y (8.8.16.3), v, (7. 4- 11.3). 



31 Calcite from Howes Cave, showing principal type of crystal. 

 Forms: M (4041)^ (7071), * (0.14.14.1)^ (0112), q (5167), 

 v (2131), U (10.4. 14.3), V (6281), N (4.16.20.3). 



32 Calcite from Howes Cave, showing a characteristic penetration 

 twin. 



