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STRUCTURE OF THE ILIMAUSAK BATHOLITE. 
While the great batholite of Igaliko as far as is known 
shows a rather simple, geological structure, the Ilimausak 
batholite contains many interesting rock types which are ar- 
ranged in an unusual manner. The details of the geology and 
petrography of this complex have been presented in the preced- 
ing chapters, and at this place the principal features will be 
considered from a more theoretical point of view. 
The Ilimausak complex of abyssal rocks can be divided 
into two parts which are very different in their geological 
structure: a western which is unstratified, and an eastern, 
Stratified part. The main rock of the western part is a 
svenite. The eastern, stratified part consists largely of lujavr- 
ites and other peculiar rock types belonging to the family of 
nepheline-syenites. 
The unstratified part of the complex. — In the unstratified 
complex the inter contact surfaces of the abyssal rocks are ge- 
nerally more or less vertical, and present the ordinary struc- 
tures found in complex batholites. 
This part of the Ilimausak complex occupies a considerable 
area in the west of the district, from Sermilik to Kakarsuak. 
South of Tunugdliarfik Fjord it occupies only a narrow zone, 
and fringes the southwestern and southeastern border of the 
stratified complex. 
The rocks of the unstratified complex are essexite, syenite 
(nordmarkite and augite-syenite), and granite. These rocks are 
generally coarse-grained even at the very contact of one rock 
‚ with another, and must all, therefore, belong to one period of 
igneous activity. Wherever a difference of age is demonstrable, 
the essexite is seen to have consolidated prior to the syenite, 
which in turn is prior to or almost contemporaneous with the 
granite. 
