0.36 Carl Fred. Kolderup. [Nr. 8 



Aadlandsfjorden in the narrow peninsula west of Tysse. The rocks, 

 which in some plaees bear rather a resemblance to the eye-gneisses 

 from the town of Bergen, may possibly be old volcanic rocks, 

 possibly granite-porphyries. This kind of rock is already known 

 from the continuation of the Rergen-arches in Rømmelø. I have 

 had analysed an eye-gneiss from the naze south of Vaagen. In a 

 somewhat irregularly foliated ground-mass with numerous small 

 specks of mica and chlorite, the microscope shows us large, irregu- 

 larly deflned individuals of felspar, whereof the greatest part is 

 microcline-microperthite and microcline; some parts are plagioclase, 

 other orthoclase, and still others consist of microperthite. The 

 interjacent mass of these grains must be regarded as a detritus 

 which is perhaps partly recrystallized. It consists of quartz and 

 felspar, numerous small folia of biotite, chlorite and some sericite. 

 Together with these folia we also see some grains of epidote and 

 titanite; some small crystals of apatite are also seen in the rock. 

 The chemical analysis and its calculation will be seen on page 126. 

 A calculation of the mineralogical composition of the rock shows 

 about 58 % felspar, 32 % quartz, 5 % mica and chlorite, 4 % 

 epidote and Va % titanite. 



Serpentines and Soapstones. 



(Pao-es 129—152.) 



In the Samnanger-area there are some occurrences of serpen- 

 tines and soapstones, which all belong to the phyllite-zone. Most 

 of the occurrences have their longitudinal direction nearly parallel 

 to the strike of the adjacent phyllites, whilst others, as for 

 instance the occurrences north of Nordvik, form an exception from 

 this rule. The rocks vary somewhat with the various areas, but 

 also within the same area there are serpentines of various kinds. 

 The essential types found are the following : 



1) Massive and homogenous dirty-green serpentine; by micro- 

 scopical investigation we can see some of the original minerals of 

 the rock these being in most cases olivine. 



2) Massive, dark-green serpentine with irregular streaks of 

 dense serpentine of a lighter colour, or with veinings of chrysotile. 



3) Massive, dark-green serpentine with aggregates of individuals 

 of magnesite and folia of tale. 



