86 
it contains many and broad veins of arfvedsonite-lujavrite and 
down by the river the lujavrite prevails. On the right side of 
the glacier-river the lujavrite extends towards the north up the 
mountain slope and reaches here its northernmost point about 
four kilometers north of Tasek. Naujaite and lujavrite continue 
along the river right up to the glacier, and the terminal moraine 
mainly consists of naujaite boulders. 
The uppermost sheet of the nepheline-syenite complex, the 
sodalite-foyaite, which at North Siorarsuit is about two hundred 
meters thick, becomes gradually thinner towards the west (see 
p. 79). No investigation was made on the mountain side north- 
east of Tasek, to see whether it was present there or not, but 
further to the north, on the south side of the glacier valley, 
the foyaite is exposed in a zone of considerable thickness be- 
tween the naujaite and the granite at a height of about 700 meters. 
The eastern part of the naujaite and lujavrite area extends 
from North Siorarsuit northwards and east of Hatten, then bends 
round towards the west and culminates at a little over 1100 
meters in the narrow ridge, which separates the Narsak Glacier 
from the cirque behind Hatten. Towards the east and north 
the nepheline-syenite area borders upon the diabase and por- 
phyry sheets. At the junction the nepheline-syenite is usually 
represented by lujavrite; east of Hatten, however, the naujaite 
comes into direct contact with the diabase. At the contact the 
size of grain of the naujaite is somewhat smaller than usual 
(the sodalite crystals average about 1'5 millimeter in diameter 
and the felspar shows rectangular sections of about 5 centimeters 
by I centimeter); the diabase is intensely metamorphosed, being 
filled with very small, dark-brown scales of biotite. North of 
this place the naujaite is separated from the porphyrite sheets 
by a zone of white augite-syenite with numerous fragments of 
porphyrite and porphyry. The highest part of the naujaite that 
forms the above-mentioned ridge south of the Narsak Glacier, 
is remarkable for its brick-red colour, which is conspicuous 
