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difference between the augite-syenite of the Igaliko batholite 
and that of the Ilimausak batholite. Furthermore it will be 
seen from the table that the Korok augite-syenite closely agrees 
with the larvikite from southern Norway, especially as far as 
the figures for lime and alkali are concerned. The main dif- 
ference is in the iron oxides. 
Border facies of augite-syenite. 
The augite-syenite, at its western border at the junction 
of the sandstone and the basement granite, shows a very 
marked endomorphic contact modification which, however, is 
only a few meters wide. Towards the point of contact the 
rock gradually becomes more fine-grained and often porphyritic. 
Sometimes a coarse-grained and a fine-grained rock alternate 
in ‘‘schlieren”. Dense modifications, not seldom with well 
developed flow structure, have also been observed in the nu- 
merous apophyses penetrating the sandstone. Examined under 
the microscope this border facies essentially displays the same 
mineral composition as the main rock: it is made up of soda- 
orthoclase (in one specimen: microperthite) and augite with 
some iron ore, apatite, and often some brown hornblende and 
biotite. As a contrast to the main rock it must be mentioned 
that in all the specimens examined of the border rock olivine 
as well as nepheline are absent, whilst in some few cases, the 
more coarse-grained apophyses, quartz enters as an essential 
constituent; it is also worth mentioning that the dark minerals 
are not crowded together in specks, but are evenly distributed 
throughout the rock. 
Occurrence of rare minerals on Narsarsuk. 
The rocks in the Igaliko batholite, the augite-syenite as 
well as the nepheline-syenite are altogether poor in rare mi- 
nerals, whilst the case is the reverse as regards the rocks in 
the Ilimausak batholite. Still there is one exception and a 
