306 
The Ilimausak batholite is of the latter kind. Its cover is 
a porphyry — the Ilimausak porphyry — which is consan- 
guineous with the batholitic rocks, and it is interesting to note 
that this porphyry, while chemically very different from the 
arfvedsonite-granite which now forms the uppermost part of 
the batholite, is very closely related to another batholitic rock, 
viz. the augite-syenite (compare anaiyses 16 and 23), which for 
other reasons must be supposed to represent the composition 
of the batholitic magma during earlier stages of the intru- 
sion. This of course does not prove that the cover has 
been produced by an outburst of the batholitic magma itself, 
but it indicates the possibility of a connection of this kind. 
Mechanism of intrusion in other parts of South Greenland. 
As far as observation goes, the Ilimausak batholite is the only 
instance in South Greenland of a batholite with remnants of 
the cover still preserved. The Igaliko batholite is situated 
within the same area of subsidence, and is also in contact with 
the Devonian sandstone; but as it rises to greater heights its 
roof has been entirely removed by erosion. In other parts of 
South Greenland a great many Plutonic rock masses occur 
which are also younger than the Algonkian Julianehaab granite, 
and are probably contemporaneous with the batholites of Ш- 
mausak and Igaliko. These, however, are situated within areas 
from which all Paleozoic sediments have been denuded, and 
their age relations cannot be determined with certainty. These 
for convenience, will be spoken of as the ‘Paleozoic’ intrusions. 
They are of great interest in discussing the question of me- 
thods of intrusion, and illustrate the occurrence of different kinds 
of intrusive rocks within a deeply dissected crystalline mountain 
plateau which is almost everywhere exposed as bare rock. 
As a supplement to the evidence obtained from the Ili- 
mausak and Igaliko batholites we give here a brief review of 
the general characters of the other occurrences. These, as 
will be seen from the following data, are in close agreement 
