74 Sterrett — New Type of Galcite from Joplin, Mo. 



on some of the smaller crystals, the quality of which allowed 

 very satisfactory determinations of the following forms : 



r (1011) 



/ (2021) 



t (2134) 



M (4041) 



'l (4045) 



(7(6178) 



m (1010) 



e (1012) 





The I face on most of the crystals is so etched as to be difficult 

 to measure. On one small crystal, however, it gave fairly 

 good reflections and an average value was obtained of m^l— 

 51° 56' ; theory 51° 43'. The C faces appeared to be only 

 vicinal growths on r, but when measured gave good reflections 

 and an average value of C*r=8° 44^' ; theory 8° 46'. 



Fig. 1 represents a quite symmetrically developed crystal 

 belonging to the Yale College collection. It was found that 

 a drawing, made in clinographic projection with the twinning 

 plane vertical, gave little idea as to the length along the twin- 

 ning plane ; so orthographic projections were also made 

 to accompany figs. 1 and 2. Fig. 2 shows the development of 



