40 



I'KNiri KSKOI.A. 



M.-N. Kl. 



Ornose, III, 5, 3, 5. 



A similar composition is common in basalts as well as in gabbroic 

 rocks, the latter always containing orthopyroxene, if they do not belong 

 to the amphibolite-facies, in which case they may consist almost exclusively 

 of hornblende. A basalt from the Hawaiian islands having nearly identical 

 bulk composition is said to contain phenocrvsts of olivine. 



In the Silden eclogite all the minerals are unaltered, excepting nar- 

 row zones around the pyroxene crystals which are turbid from incipient 

 separation of diopside-plagioclase-myrmekite. These zones are so thin that 

 they rather appear as thick boundary-lines drawn with a coarse pencil. 



The structure is shown in hg. 4, pi. I. Parallel arrangement of the 

 minerals is not very pronounced. The rutile is found equally enclosed in 

 all the minerals, the garnet shows crystalline forms towards the pyroxene 

 and quartz, while the pyroxene is always irregular. 



The Eclogite from Saltkjael, Selje, Xo/yf/jort/. 



In the collections of the Geological Museum in Christiania there exi.sts 

 a specimen collected by H. Reusch and marked "from a 3 foot thick layer 

 in gneiss, Saltkjael, Selje". The rock is aphanitic, and at first sight I 

 thought it to be some hornfels. Microscopic observation revealed garnet 

 and c 1 i n o p y r o X e n e as the main minerals, besides a little pale brown 

 mica. The average pyroxene grain is 0.15 mm in diameter, while the 

 rounded grains of garnet attain 0.3 mm. 



