-252 Carl Fred. Kolderup. [Ni 



of the phyllites are alura-slate-phyllites. The colour of the ordi- 

 nary phyllites varies from greyish to greenish, while the alura- 

 slate-phyllites are black with variegated weathering colours. Both 

 types contain lenses of quartz, sometiraes with remains of calcite, 

 which probably derive from original lumps of calcite similar to those 

 founcl in the clay-slates in the Kristiania-area. Some gneissose 

 rocks, serpentines, soapstones, greenschists, tine-grained saussurite- 

 diabases and saussurite-gabbros also occur in the phyllite-zone. 

 Probably the gneissose rocks have eithcr been old volcanic rocks, 

 or also injected masses. At some places there seems to have been 

 a considerable supply of albitc in solution. 



The serpentines and the soapstones closely related to them 

 may safely be considered as metamorphosed igneous rocks ; prob- 

 ably the original rocks were peridotites or perhaps pikrites as in 

 the extensive area of Raunipen. 



The green-schists and the saussurite-diabases which occur at 

 different places in the phyllite-zone, have likely originally been 

 basic volcanic rocks and tufts. Similar rocks are found on the 

 western border of the phyllite-zone in the green-schist-zone of 

 Kraanipen. Probably thcse are tuffs. The saussurite-gabbros at 

 Aldal and Gjerde chiefly give the impression of metamorphosed 

 gabbros. 



The limestones which have been altered into marble, are of 

 a decidedly sedimentary origin, and occur in a zone in the western 

 part of the area, which is intersccted by several dislocations. The 

 fossils here found indicate their origin in the Middle-Silurian age, 

 the schists most probably belonging to stage 5 a. 



The polymict conglomerate, which is identical to the so-called 

 Moberg-conglomerate in the tracts of Os, contains at several places 

 fragments of the marble above mentioned, and cannot therefore be 

 older than Middle-Silurian. On account of the nature of the cementing 

 matrix and because of the general character of the conglomerates, I have 

 thought it probable that here we have to do with a volcanic conglome- 

 rate, the cement of which originally consisted of ingredients of tuff. 

 During the folding masses of granite have been injected in the 

 conglomerate, and have to a greater or smaller extent assumecl a 

 gneissose appearance. 



The so-called "green gneiss" is a rock of somewhat varying 

 composition, but which probably is of a similar origin as the poly- 

 mict conglomerate. 



