1914—15] Fjeldbygningen mellem Sørfjorden og Samuangerf jorden. 253 



The rock designated by Reusch as "grey gneiss" must, how- 

 cver, according to the investigation which has been made, be 

 regarded as a compressed granite, this being also the case with the 

 partly gneissose rocks, which occur on the western side of the 

 greenschist-zone of Kraanipen. 



As mentioned, granitic dykes of somewhat different habitus 

 also occur in (he area together with dykes which must chiefly be 

 regarded as metamorphosed saussurite-diabases. 



The western border of the rock-zones mentioned above, is 

 occupied by the saussurite-gabbros and gneissose rocks of Gul- 

 fjeldet. These rocks are compressed granites, which have pene- 

 trated the saussurite-gabbros, of which they eontain fragments. 



The eastern border is formed by a zone of compressed 

 labradorite-rocks and othcr relative rocks, mangerites, birkremites, 

 norytes and pyroxenites. 



In the north-eastern corner of the map we finally tind a varia- 

 tion of gneisses, probably Archæan gneisses, and phyllites, which in 

 the same way as the series of layers of the Bergen-arches are 

 pressed as folds into the Archæan. In the tracts south of \ r aksdal 

 we are tims getting a kind of "Schuppen-Structur", which con- 

 tributes to the understanding of the tectonic relations of the 

 Bergen-arches. 



As may be scen on the general map of the Bergen area 

 (p. 10) the so-called "Guter Bergen Arch" stretches from Os across 

 Samnanger to Osterøen and henco farther north on the continent 

 west of Fensfjorden. It being of interest to see which rocks are 

 contained in the different tracts of this zone. I have (on page 210) 

 tabulated G different sections across the arch. The profiles are 

 stated consecutively from south to north. 



1. The district of Os (Søfteland— Bjaanes). 



2. Samnanger (Haugen — Storenut). 



3. The south side of Ostcrø (Stokke— Bruvik). 



4. The north side of Osterø (Veten— Fotlandsvaag). 



5. The north side of Osterfjord (Dyrsvik— Askviknes) 



6. Northernmost at Lindaas (Vabønes). 



As may be observed wiren regarding these sections, the rocks 

 as well as their mutual relations vary in the different parts of the 

 arch. The farther north we advance, the narrower grows the arch, 

 and the more metamorphosed its rocks. The rich variation of 

 different rocks in the southern part gradually diminishes toward 



