1914 — 15] Fjeldbygningen mellem Sørfjorden og- Samnanger f jorden. 223 



The Series of Layers to the West of Trengereid 

 Railway Station. 



(Pages 36—63.) 



As is evident from the detailed investigations, the above zone, 

 which stretch es westward to the border of the gneiss-area of Ulrik- 

 ken and eastwards to Trengereid railway station, shows an exceed- 

 ingly rich variety of rocks, of which it is difflcult to get a survey 

 because of the steep and partially overgrown ground. If we regard 

 the section on plate II, the zones up to, and including VI, must 

 be reckoned to the gneiss-area of Ulrikken; III and IV, however, 

 are zones of phyllite and hornblende-schist, which during the 

 folding have been pressed into this gneiss in a similar way as the 

 phyllite-zones have been pressed into the Archæan gneiss on the stretch 

 Boge — Vaksdal in the north-eastern part of the map. The Silurian 

 layers commence with the strougly compressed conglomerate in zone 

 VII, which may be parallelized with the Moberg-conglomerate in 

 Os, and until we get eastwards to the large zone of green gneiss, 

 somewhat east of Trengereid, there is a variation of strongly pres- 

 sed conglomerates, marbles, quartz-sericite-schists, hornblende-schists, 

 gneissose rocks, and finally outcrops from the large saussurite-gab- 

 bro-area in Gulfjeldet, In the marble-zones traces of fossiles have 

 been found, similar to those found in the southern parts of the 

 Samnanger-area and in the tract of Os; these belong to the 

 middle Silurian age. The conglomerates which in some zones are 

 so strongly pressed that the conglomerate-structure is difficult to 

 make out, may undoubtedly be parallelized with the Moberg- 

 conglomerate; and as pebbles of marble of the same species as just 

 mentioned are found in this conglomerate, the latter is, as already 

 shown in an earlier treatise, of Silurian age. 



The quartz-sericite-schists most likely correspond to the quartzi- 

 tic sandstones in Os, where the transformation is considerably 

 less intense. The hornblende-schists are principally metamorphosed 

 basic superficial rocks or tutts; at any rate the gneissose rocks 

 have in several cases been proved to be of eruptive origin (see the 

 analyses pages 41 and 47). The saussurite-gabbros are to be re- 

 garded as strongly pressed outcrops from the saussurite-gabbro-area 

 of Gulfjeldet, They have a distinct ' : flaser"-structure. While some 



