46 



several hundred pieces, most of which contain a very great 

 number of crystals. Among these it has been possible to 

 separate some different types, of which a few are rather rich in 

 faces, and have made an excellent crystallographic material. 



The geological structure of the mentioned localities is 

 briefly as follows Ч: Round the innermost part of the Kanger- 

 dluarsuk-Fjord and across the Tunugdliarfik-Fjord stretches a terri- 

 tory with more recent plutonic, partly very characteristic rocks, 

 some of the most characteristic of which have been described 

 by N. V. Ussing in Rosenbusch: Mikr. Physiogr. 1896. The 

 chief portion of the territory consists of the very coarse-grained 

 sodalite-syenite, which contains generally numerous layers or 

 lenses of fine-grained lujavrite. Along the outer borders of 

 these rocks several more acid rocks are often found, one belt 

 round about the other; nearest to the sodalite-syenite is found 

 a foyaite, more or less rich in eudialyte, next comes some 

 augite- syenite, and in a few places more recent granite. In 

 some places these rocks border on the Archæan rocks, in other 

 on the layers of sandstone and diabase lying over the Archæan 

 rocks. In the localities where the ilvaite is found, the different 

 kinds of syenites have been subjected to a very thorough trans- 

 formation, which, when most complete, involves the fact that 

 all the lighter minerals have become albite or perhaps other 

 varieties of feldspar, while all the darker minerals have become 

 ilvaite. Besides these two elements smaller masses of green 

 garnet are found, as well as microscopic crystals of epidote 

 and some other minerals to be mentioned hereafter. The pro- 

 cess of transformation itself will not be more particularly men- 

 tioned here, as the other minerals have not yet been examined 

 more closely. The structure of the rocks has in most cases 

 been tolerably well preserved, so thai their original nature may 



^) Comp, the geological map of Uie district of Julianehaab by G. F. Holm 

 and K. J. V. Steenstrup. The present journal II. 



