1914 — 15] Fj eldby gningeii mellem Sørfjorden og Samnangerf jorden. 243 



specific gravities of the three separated portions of microperthite 

 are 2,608, 2,598 and 2,571. In C is a greyish to reddish rock with 

 irregular lens- or streak-shaped parts chiefly consisting of green 

 hornblende, epidote and some green biotite ; some pyrite, titanite, 

 magne tite and zirkon are also seen. In the light-grey chief mass 

 are seen small reddish "eyes". By microscopical investigation the 

 latter appear to consist of microperthite and some microcline-micro- 

 perthite. The greyish mass, on the other hand, consists of a detritus 

 of quartz and felspar, which at any rate partly is microperthite. 

 (Fig. 81.) 



In CXIV wc lind a number of streaked birkremite rocks of 

 somewhat various composition. 



The Dykes. 



(Pages 168-173.) 



The dykes are on the whole of little extent both in length 

 and Avitdh. The rocks are either basic, and then generally saus- 

 surite-diabases or else acid granitic rocks. All are more or less 

 metamorphosed by pressure and must have penetrated before the 

 folding-process was quite terminated. The saussurite-diabases are 

 upon the whole of a schistic structure and are rather fine-grained. 

 In several instances hornblende is quite the predominant mineral. 

 Figs. 82 and 83 show the structure of these rocks. 



Near these rocks there are the greenish dyke-rocks which have 

 been described and regarded by Rekstad as complimentary to the 

 aplitic dykes occuring in the phyllites. These greenish rocks of 

 partly porphyry structure consist of felspar (chiefly plagioclase), 

 zoisite, chlorite, some biotite and some calcite. The chlorite is 

 formed by metamorphism of biotite and hornblende. 



There are different types among the granitic dyke-rocks. One 

 of these types consists of a whitish or greyish fine-grained horn- 

 blende-mass with rather large black needles of hornblende, the 

 length of which can attain the length of 1 cm . and with crystals 

 of garnet. The fine-grained ground-mass consists of quartz and 

 felspar, which is chiefly plagioclase. In \ T iew of the fact that I 

 have found a dyke of this type intruding the granite-zone of Kraa- 

 nipen (fig. 85), I must regard these dyke-rocks as most probably 

 belono-ing to the youngest of the rocks of the area. 



