276 



hornblende and a margin of a crossitic amphibole, are found in 

 small qnantities in tlie rock. 



IntergTOwths of crossite and actinolite have been described from 

 other localities, those of crossite and common hornblende will be 

 described more in detail. 



In a section, the crossitic amphibole of which showed a strong 

 pleochroisffi from blue to nearly colourless, the central part was 

 pleochroic from light brownish yellow to darker brownish yellow ; 

 in the marginal zone the crossite showed an extinction angle of 

 14'', which towards the centre gi-adually decreased to 9"^, whilst 

 in the common hornblende this angle gradually increased to 17°. In 

 both amphiboles the prism axis is parallel to the slow ray. 



In a section, the crossitic amphibole of which was pleochroic 

 from slightly bluish violet to blue, the central part showed the 

 darker brownish yellow^ colour and was only \'ery little pleochroic. 



Fig. 1. 

 lutergi owth of cros- 

 sitic and brownish 

 yellow amphibole. 

 Section + parallel 

 to (010); X200. 



Fig. 2. 

 Id. Section ± parallel to (100); 

 X200. 



In this section the prism axis of the mai'ginal zone was parallel to 

 the fast ray, whilst that of the central zone was parallel to the slow 

 ray. In the section small oblique extinctions were seen, so that it 

 was not exactly perpendicular to the plane of symmetry. 



