51 
decomposed. This coating gives the augite-syenite cliffs a con- 
spicuous, reddish brown appearance. 
Contact-facies of the augite-syenite. — The augite-syenite 
shows a very marked, endomorphic contact-modification at its 
southern and south-eastern border, where it comes into contact 
with the old granite. This contact-facies is a fine-grained, 
white or gray rock in which the black minerals appear as small 
dots; locally the structure is porphyritic, due to the presence 
of phenocrysts of felspar. On the south shore of Kangerdluarsuk, 
right opposite the Niakornarsuk Peninsula, this border-zone 
has a breadth of 4 to 10 meters, and in it occur a few irregular 
veins, 1 or 2 meters broad, of a newer granite. On the north 
side of Iviangusat, at an altitude of 6—700 meters, there is a 
zone, about 8 meters broad, of a characteristic, fine-grained, 
dark-gray rock between the syenite and the old granite (or 
perhaps in the granite but very near the contact); this rock 
forms a dark band conspicuous even at a distance. Seen under 
the microscope, it consists of egirine-augite and anorthoclase 
with some titanite and iron-ore; the structure seems to have 
been modified by contact-metamorphism. This rock is perhaps 
a dyke or a remnant of an ancient border-facies. Further to 
the east and near the foot of Kitdlavat the solid rock only 
projects from the debris-covered plain in small, isolated patches, 
but so far as could be observed, the augite-syenite with its 
usual fine-grained centact-modification borders directly on the 
Algonkian granite along the whole of this stretch. 
The junction of the augite-syenite with the nepheline- 
syenites is only exposed at quite a few places already referred 
to (pp. 47—50), and it will be seen from what has been 
said, that the augite-syenite has consolidated earlier than the 
nepheline-syenites. It follows from this that the augite-syenite 
is not a dyke, but constitutes the first consolidated part of the 
batholitic complex. 
The sandstone-fragments. — At the northern foot of the 
4* 
