220 Carl Fred. Kolderup. [Nr. 8 



A petrograpliical examination of the metamorphosed gabbro- 

 rocks from Gulfj eldet shows that we have here to do with two 

 principal types: (1) The saussurite- or zoisite-gabbro without 

 note-worthy pressure-structure, and (2) more or less thinly schistose 

 saussurite-gabbro-schist or zoisite-hornblende-schist. 



The typical saussurite-gabbros have in most cases preserved 

 their original strncture. The metamorphism which has tåken 

 place, consists in the diallage having been altered into hornblende 

 with diallage-like polarization-colours, and in the alteration of 

 plagioclase to a mixture of zoisite-epidote, some albite and quartz. 

 Several of the granular varieties of uralite-gabbros and uralitisized 

 pyroxenites have a partial streaked arrangement of their components, 

 and tims a petrograpliical transition to the schistose, occasionally 

 fine-grained varieties, is prepared. The latter are either pure 

 hornblende-schists, or felspar-bearing more or less saussuritisized 

 hornblende-schists, or also zoisite-hornblende-schists. 



In the cross-section from the railroad we have a good opportu- 

 nity of studying the outcrops from the saussurite-gabbro-area, and 

 the four zones nos. XXX, XXXV, XXXVII and XXXIX have 

 accordingly been subject to a clcse examination. 



Already on my first excursions in the mountains S. W. of 

 Trengereid railway station, I found rather large masses of greyish, 

 gneissose rocks, which were mapped down. Through their homo- 

 geneous aspect and their position on the borders against the saus- 

 surite-gabbros, these rocks make in several localities, despite their 

 schistose strncture, the impression of being compressed eruptive rocks. 

 In several places my assistents and myself have also found dykes 

 from the gneissose masses in the saussurite-gabbros. Fig. 6 displays 

 a dyke of compressed granite of greyish-white colour intersecting 

 a rather large flake of saussurite-gabbros, which is on all sides 

 surrounded by the gneissose compressed granite. Besides the some- 

 what larger dyke we also see smaller granitic veins, which because of 

 their lighter colours make a contrast to the dark saussurite-gabbros. 

 The saussurite-gabbro-flake lies at an elevation of about 500 m. 

 above the sea-level and directly east of Southern Maasetjern (west 

 of the map). The light-coloured dyke-rock exhibits i'ather a parti- 

 cular structure, there being in the fine-grained whitish felspar-mass 

 some elliptic and more coarse-grained aggregates of quartz. Possi- 

 bly we have a protoclase-structure. Of minerals are seen: Felspar, 

 which in any case partially is plagioclase, quartz, partially chloriti- 



