256 On! Fred. Kolclerup. [Nr. 8 



correspondenco with the layers at Os; I have not in Bergen found 

 any of the varieties of rocks typical of the Silurian series at Os and 

 Trengereid, it should be some single modifications of hornblende and 

 some saussurite-gabbros". This comparison applies to the relation 

 between the inner Bergen-arch in and about Bergen and the outer 

 arch in the district of Os and in part of Samnanger. According 

 to our present knowledge the rocks at Os betong to thoso which 

 have undergone the slightest metamorphism, and they therefore 

 show the least correspondenco with those of the inner arch. In 

 order to obtain a proper comparison it is necessary to consider the 

 arches in their whole extension. The principal rocks of the inner 

 Bergen-arch are: phyllitcs, marbles, quartz-schists, congiomerates, 

 hornblende-schists and saussurite-diabase-schists (the latter partly 

 with intrusive veins of grey aplitic rocks),, eye-gneisses and serpen- 

 tines; the latter I have found south of Nordaasvandet, Do theso 

 rocks occur and with the same degrec of metamorphism in the 

 outer arch? As for the phyllitcs Ave know that these play an 

 important part in the outer as well as the inner arch, and phyllites 

 of the same type as those of the town of Bergen are found partly 

 in the area of Samnanger, and also in Osterøen and farther north. 

 The phyllites at Os and most of those in Samnanger are less meta- 

 morphosed than the former, but in the inner Bergen-arch, for instance 

 at Nestun, we have also phyllitcs which show a slighter metamor- 

 phism than those from Bergen. The phyllites of Nestun remind one 

 rather much of those of the area of Os, and look as if we might entertain 

 a slight hope of tinding fossils thcre Marble has been found 

 in the inner Bergen-arch in Marmorø (the islet of marble) at 

 Fjøsanger, at Tveteraas and at Nygaard. It is indeed strongly 

 metamorphosed, although no more strongly than in the northern 

 oecurrences in the outer arch, where no fossils have been found. 

 The quartz-sericite-schists and the associating congiomerates in and 

 at Bergen correspond to the quartziferous sandstones and congio- 

 merates at Ulvenvand and to the quartz-sericite-schists in the area 

 of Samnanger. The tinc-grained, greenish hornblende-schists and 

 the closely related saussurite-diabase-schists in and about Bergen 

 correspond to the green-schists, the hornblende-schists and the saus- 

 surite-diabase-schists in Os and Samnanger and are undoubtedly 

 old volcanic rocks and tutts. Fine-grained, greyish-white aplitic 

 dykes are found in these rocks in both arches. Having found a 

 serpentine-occurrence south of Nordaasvandet I have obtained a 



