193 



and bronglit to liglit tli;it tlie mineral nnder consideration gelatinized 

 sooner than the olivine. In the liqnid that had been collected inicro- 

 cheinicallj the presence of calcinni could not be detected. 



Finally each individual lath was examined conoseopicallj ; thus I 

 succeeded in establishing in several ot thein that the mineral 

 is biaxial, and that the axial plane is always perpendicular to the 

 longer axis, the elongation being always positive. This is possible 

 only if the mineral is developed into tlakes perpendicular to the optical 

 A-axis; it thus became more and more probable that the mineral 

 could be rhombic. If so we must have to do with antigorite in its 

 primary form. 



The idea of a secondary postmagmatic genesis should be dro|)ped 

 altogether, the antigorite laths traverse freely from one olivine- 

 crystal intf) another; subsequently they form with them as it were 

 a entectic crystallization and ultimately become the predominant 

 mineral (See the microphoto fig. 1 and 2). AH this applies to the 

 material rich in large magnetite masses. Other material, finer grained 



-. :~'T^r'zy^'.7-y*\ . . 







"1^^ 















'k4;i/:/^'m^- 



^ ■ "A^V 



:^/- 



Fig. 1. Primary antigorite in olivine. 



