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position that sediments have been absorbed on a large scale in 
the upper part of the batholite. It is found that, although the 
Plutonic rocks of both districts, from a chemical point of view, 
belong to similar types (nepheline-syenites, soda-syenites, soda- 
granites), the sediments invaded are very different. Thus, while 
in the Christiania district the Plutonic masses are often bounded 
by limestones and shale, sediments of these kinds are entirely 
absent at Julianehaab'. Moreover, when the junction of the 
Ilimausak batholite with the country rock is studied in detail, 
it is found that indications of a marginal assimilation are 
entirely absent at many places. This applies to the whole 
contact surface between the arfvedsonite-granite and the over- 
lying porphyry; probably it holds good also of the contact be- 
tween the batholite and the Algonkian granite south of Tunug- 
dliarfik. 
It is easy to see, however, that these arguments do not 
suffice to refute the assimilation hypothesis. All that can be 
concluded is that the bulk of the visible part of the Ilimausak 
batholite is not an assimilation product, but consists of material 
which has originated from some unknown source in the interior 
of the earth, and that if assimilation has played any part in 
the mechanism of intrusion, it must have been accompanied by 
other processes. Now proofs are not wanting that a local 
assimilation of the invaded rock has actually taken place at 
llimausak. Thus, both the augite-syenite and the lujavrite pass 
! The complete absence of carbonate-rocks in the whole country around 
the very large nepheline-syenite areas of south Greenland is inconsistent 
with the hypothesis recently set forth by Day relating to a genetic 
connection between carbonate-rocks and nepheline-syenites (Origin of 
the Alkaline Rocks. Bull. Geol. Soc. of America XXI, p. 87, 1910). 
The only carbonate bearing formation of South Greenland is the Arsuk 
group (р. 9). The possibility that dolomites of this group have once 
existed at Julianehaab cannot be denied. But the late-Algonkian igneous 
series (Julianehaab granite etc.) which is later than the Arsuk group 
consists of sub-Alkaline rocks. Thus, actual observations tell against 
the hypothesis in every way. 
