99 



Type [II. 



The catapleiite crystals of the third type are also small, 

 attaining a breadth of V2'=" at most and a thickness of one or 

 two mm. They are, consequently, rather thick compared with 

 those of type II as Avell as in proportion to their width. Strictly 

 speaking, only one specimen with typical crystals of the kind 

 in question has been found. On this, however, there is plenty of 

 material, as it consists for the most part of catapleiite crystals. 

 These are comparatively rich in faces and excellently developed. 

 Besides, I found a number of specimens with catapleiite crys- 

 tals somewhat differing from these, but which may justly be 

 referred to the same type. They are less perfectly developed 

 with regard to their faces, as only the base is plane and bril- 

 liant, while the rest of the crystal is so rounded that pyramidal 

 and prismatic faces can hardly be determined. In colour, lustre 

 and mode of occurrence, however, they perfectly agree with the 

 better developed crystals of the third type. Whether the imper- 

 fect development of these crystals is original or secondary, 

 cannot, probably, be determined with certainty. 



On the perfectly developed catapleiite crystals of the third 

 type the following forms occur: 



с =- {OOOl}, m = {lOTo}, ij = {ЮТЗ}, = {l0T2}, 



p == {loTi}, X = {2021}. 



This complete combination is represented by Fig. 9, Plate V. 

 In general all the faces of the forms are present on every 

 crystal individual. Among the pyramidal faces those in the 

 middle, and p, are generally somewhat wider than the two 

 others, but also у is often rather wide. All the faces are, as 

 a rule, very smooth and give excellent reflections, so that very 

 accurate measurements could be made. The results obtained 

 on a crystal excellently developed on all sides are given below. 

 The calculated values annexed are referred to the axial ratio 

 estabhshed for the Norwegian catapleiite. 



