192 
magma has become so completely altered that it has consoli- 
dated as a true soda-granite. The occurrence is described in 
p. 53 and p. 116. | 
NORDMARKITE. 
The nordmarkite covers an area of about) 12 km? in the 
extreme west of the peninsula between Sermilik Fjord and Tu- 
nugdliarfik Fjord. It is a coarse-grained, flesh-coloured or 
grayish-red alkali-syenite. In habit it shows considerable 
likeness to Bröscer’s original nordmarkite from the district 
of Christiania. The macroscopic description is given p. 98. 
Microscopic characters. — In thin sections under the mi- 
croscope the minerals seen are apatite, iron-ore, biotite, augite, 
ægirine-augite, hornblende, felspar, and frequently quartz. Ægir- 
ine, arfvedsonite, and ainigmatite have been observed in some 
specimens of this rock, fluorite only in one specimen. Calcite 
and brown or black ferruginous material are not seldom found 
as alteration-products of the ferromagnesian minerals. 
Apatite is abundantly present in small prisms. Jron-ore, 
in more or less irregular grains is not so abundant as in the 
augite-syenite. Ц is mostly magnetite (or titano-magnetite) but 
small crystals of pyrite may sometimes be found. Where the 
rock contains quartz in greater quantity, the amount of apatite 
and iron-ore is diminished. 
The biotite is strongly pleochroic, the absorption tints va- 
rying from a very dark red-brown or greenish: brown to quite 
pale yellow. It often surrounds the iron-ore and occurs in greatly 
varying quantities. 
Augite in rounded grains or allotriomorphic anhedra is 
rather abundant in some specimens, in others it is scant or 
absent. It is colourless, pale gray or greenish. In sections 
parallel to the plane of symmetry (010) the angle of extinction 
