1882.] 



from Wheal Newton. 



241 



The crystal has a peculiar hemimorphic development due to the 

 preponderance of one set of the planes p, z, n over the others of 



(%• I)- 



the same forms. This is to a certain extent shown in the diagram 

 (fig. 2), which is a projection of the crystal on the plane c. The 



(fig. 2). 



crystal is, however, not so wide across in comparison to its length as 

 is shown in this diagram. The crystal is, moreover, much traversed 

 by twin laminae and twin striations, which are not similarly de- 

 veloped on like planes, or even on all parts of one and the same 

 plane. Thus the two planes p are finely and regularly striated, as 

 shown in the diagram, except in a small portion of one of them 

 adjoining the plane X. The large plane p has a few striations, or 

 rather thin lamina? traversing it, perpendicular to the edge [p f m r \. 

 A well-marked lamina traverses the small planes p', z, n. Few 



