65 



paying regard to the most pronounced reflexes, we get a very 

 strong guarantee that the faces found are genuine ones. 



The prismatic zone is the most striated of ail; here is 

 found an almost continuous series of reflexes from i(010} to 

 Л (210}, while between this face and the opposite one A {2T0) 

 no single one is found. 



The zone of brachydomes is very characteristic; in all the 

 crystals it is highly striated in a part round w{012}, and here 

 numerous reflexes are found, among which it has not been 

 possible to distinguish any definite form. 



In a few crystals the part between /"{04l} and è(010} is 

 also very highly striated horizontally without it being possible 

 to point out any single form among the large number of re- 

 flexes. The piece of the zone situated between /"{оя} and 

 ^(Oll/, on the other hand, is never striated, and consequently 

 the reflexes are seen exceedingly clearly, ^{oil} is not found 

 in very many crystals, and is always very narrow. 



The zone (010, 101) is highly striated in a part extending 

 from w{l3l} to P{lOl}. The other faces «/{ЗИ}, а;{4П}, and 

 £{431} are not striated in any particular direction, but irregu- 

 larly grooved and furrowed. 



II. Ilvaite from the Foyaite. 



Around the sodalite-syenite stretches generally a more or 

 less broad belt of rather large-grained foyaite, most frequently 

 very rich in eudialyte, like the sodalite-syenite itself. Imme- 

 diately adjoining the part of the occurrence of ilvaite belonging 

 to the sodalite-syenite and the lujavrite, is also found a smaller 

 part, which, as far as may be judged from the structure of the 

 rock and the nature of the feldspar, cortsists of transformed 

 foyaite. The transformation of the different minerals, however, 

 has here been very thorough. The only one which may still 

 be recognized, is the feldspar, which appears as flat, thin plates 



