130 



present figure, therefore, exhibits not only a rare specimen 

 of Carbonate of Lime, but some varieties in the facets of 

 the pyramids. The upper figure is a small group with 

 pointed endings. The lower figure has the same faces with 

 lateral additions, and one is terminated at both ends. I have 

 added parts of two other varieties underneath, which occa- 

 sionally form groups. The upper right hand geometrical 

 outline shows one end of a crystal with a narrow face, 

 which is placed upon the acute edge of the pyramid. The 

 next outline beneath exhibits narrow faces on the terminal 

 edges of the prism, with a minute truncation upon the 

 acute angle, making three additional facets to each solid 

 angle : the obtuse end contains three of the primitive faces. 

 I have a group to correspond with the faces of the column, 

 alternating; narrow at one end and broader at the other. 

 The right hand figure has an equiangular pyramid with a 

 truncated apex, nearly like Haiiy's fig. 32. This is rare : 

 it is from Derbyshire. 



