95 



the tables. But a regular intergrowth that might be denoted as 

 a twin formation 1 have not been able to ascertain. It is, 

 indeed , attended with great difficulty to make Out a possible 

 presence of twins, where no faces but the base give distinct 

 reflections. 



Catapleiite of type I has been found on NarsarsUk only 

 at the locality No. 3. The mineral occurred there almost 

 exclusively as detached crystals or crystal groups. Not a 

 trace of any other mineral was found grown together with 

 them. Only on a couple of specimens catapleiite occurs in 

 combination with other minerals. On one of these specimens 

 the catapleiite crystals are implanted on albite crystals, which 

 are, themselves, of secondary origin. On the other specimen 

 numerous small catapleiite crystals occur implanted on aegi- 

 rine individuals. From this it may be concluded that this kind 

 of catapleiite is a secondary formation, though earlier than 

 most of the numerous other secondary minerals that occur in 

 this place. 



Type II. 



The catapleiite crystals of this type are much smaller in 

 size than those of the foregoing type. They are not over 3""" 

 in diameter, and their greatest thickness is little more than 

 i/^mm They are mostly aggregated into irregular druses which 

 line the walls of small cavities in the syenite. Sometimes a 

 rather large number of crystals are grown together in parallel 

 or nearly parallel position, forming a crystal group with step- 

 like sides. 



These catapleiite crystals are also very simple with regard 

 to the combination of faces. Only the following four forms 

 have been observed. 



с = {OOOI}, = {10T2}, p = {lOTl}, m = {lOTo}. 



The first three forms are always present (Fig. 8, Plate V). 



