186 
occur, viz: zircon, ainigmatite (?), ægirine-augite, catophorite- 
like hornblende, arfvedsonite, cryptoperthite, microperthite, and 
quartz. 
The apatite, which is almost entirely wanting in the 
nepheline-syenites and lujavrites of this region, occurs invari- 
ably and in relative abundance in the augite-syenite, partly as 
small and slender prisms enclosed in the augite, partly in 
larger grains and stout crystals that may attain a diameter of 
one millimeter and are irregularly dispersed in the rock. Iron- 
ore is a constant component; it is rather frequent, in crystals 
and irregular laps. It is sometimes accompanied by small 
titanite-like grains and seems to be highly titan-bearing. An 
ainigmatite-like mineral has been found as a subordinate con- 
stituent in only two specimens of olivine-bearing augite- 
syenite. 
Olivine is abundant in the main type of the rock but in 
other varieties it may be entirely absent. It is quite fresh and 
has the form of grains or very imperfect crystals that may 
attain a diameter of !/2 centimeter. In thin slices the mineral 
is colourless or of a faint yellowish-green. Sometimes it is filled 
with close-lying black lines due to linear-shaped inclusions 
imbedded parallel to (100) and elongated parallel to the cry- 
stallographic b-axis. These inclusions are metallic and, where 
they are very thin, brownish and translucent. Probably they 
consist of ilmenite. They produce a schiller-structure of si- 
milar but much coarser kind than that observed in the pyr- 
oxenes. 
Biotite is an almost constant but quite subordinate consti- 
tuent. It is strongly pleochroic with absorption-tints from pale 
yellow to almost black. 
The commonest pyroxene in the augite-syenite is a faintly 
coloured augite characterized by an extinction-angle c :c of 
about 42°. The pleochroism is not very pronounced the ab- 
sorption-tints varying from quite pale brownish-violet to some- 
