254 Carl Fred. Kolderup. [Nr. 8 



the north, and finally we lind only phyllites and a small oecurence 

 of serpentine. The same decrease of breadth from south to north 

 is also observed in the inner Siluriah arch of the Bergen-area. 

 This indicates a drawing out of the northern part of both arches. 

 Probably we have, as already suggested, originally inclined folds, 

 which have now been eroded to a relatively horizontal level. Origi- 

 nally I thought I should succeed in proving distinct folding of the 

 various rock-zones of the outer arch by means of the minute inve- 

 stigations which have now been made. This has, however, proved to 

 be impossible. In places, as for instance in the cross-section of 

 Stokke— Bruvik, a partial repetition of the zones may indeed be 

 seen, and thus we may regard the whole complex as a single 

 original fold; but this is also the only section which, although 

 but in part, could lend support to such a supposition. By con- 

 sidering the whole outer arch we get the impression that it consists 

 of a good many different rock-zones, which through the intense 

 folding has got an approximately parallel arrangement, and which, 

 if we follow it in a longitudinal direction, gradually is drawn out. 

 In this way it may be explained that the series of layers differ 

 in Samnanger and Os. and also on the nothern side of Oster- 

 fjorden. It also seems as if some cross-faults have exerted their 

 influence on the arrangement of the rock-series. I may thus 

 mention, that in the district of Os we have a fault stretching along 

 the longitudinal direction of Ulvenvand, as suggested by Reusch; 

 and, as shown above, we have in any case two somewhat greater 

 cross-faults in the Samnanger-area, and that finally it is probable 

 that we have some dislocations along the southern part of Sør- 

 fjorden, the latter explaining the above-mentioned difference in 

 the succession of layers on the southern and northern side of this 

 part of the fjord. In spite of these dislocations, however, and 

 because of the correspondencies with regard to the general habitus 

 and the geological oecurence of the rock-zones it must be considered 

 as beyond all doubt that the rocks which now constitutc the 

 entire outer arch, have once belonged to a series of layers which 

 as an entire whole have been pressed down into the Archæan. 

 Zones similar to the Bergen Silurian arches, but more narrow than 

 these and notably consisting of phyllites, have. in a somewhat 

 similar way to that mentioned above, been pressed down into the 

 Archæan in the tract south of Vaksdal. These zones taper toward 



