103 
JUNCTION OF THF NORDMARKITE AND SANDSTONE. 
In Sermilik Fjord the junction of the nordmarkite and 
sandstone is finely exposed just under Mount Steenstrup. The 
plane of contact is almost vertical and at a right angle to the 
shore-line. Towards the contact the nordmarkite becomes fine- 
grained and porphyritic; about one meter from the sandstone 
it passes into a quartz-bearing syenite-porphyry consisting of 
a brownish-gray, fine-grained, ground-mass with thick, tabular 
felspar phenocrysts about one centimeter long. Still closer to 
the sandstone the rock becomes so rich in quartz that it must 
be characterized as a granite; the structure here is medium- 
grained and the colour light-brown. Microscopic examination 
shows, that the quartz-grains of this contact-facies are not 
sandstone fragments, but have crystallised together with the 
other constituents. Thus, the syenite magma appears to have 
absorbed a very considerable quantity of silica from the sand- 
stone, in a zone along the contact about one meter broad. 
At the contact with the nordmarkite the sandstone ex- 
hibits distinct effects of contact-metamorphism: it has become 
quartzite-like and the red colour has disappeared. Under the 
microscope the interstitial matter of the sandstone is seen to 
have entirely disappeared and the rock consists of clear inter- 
locking quartz grains. The white quartzite-like contact-zone 
has a breadth of some meters. 
TOTAL THICKNESS OF THE RED SANDSTONE AND 
OF THE VOLCANIC SERIES. 
The natural section exposed on the south side of Sermilik 
Fjord gives us a means of forming a fairly trustworthy estimate 
of the thickness of the red sandstone. The beds have a very 
regular inclination of about 2° on the average towards $. 5. W. 
At the head of the small side-fjord Kangerdluak (furthest to the 
left in the section Pl. VI, Fig. 2), the basement rock appears 
