57 
porphyritic with numerous tabular erystals of plagioclase about 
half a millimeter thick and 6 millimeters long. Epidote and 
calcite are often seen as alteration-products. At the junction 
towards the underlying sandstone the diabase assumes a dense 
structure. As will be mentioned later, this diabase may be 
classed as a trachydolerite, according to the system of ВозЕмвозсн. 
A comparison with the sections north of tbe Tunugdliarfik 
Fjord shows, that the diabase at the top of Nunasarnausak is 
an intrusive sheet, the original sandstone cover of which has 
been removed by erosion. The diabase is cut by several dykes 
of a reddish brown syenite-porphyry which have the direction 
NNW SSE 
Fig. 9. Nunasarnausak, from УМ. $. W. 
The hills in the foreground are Algonkian granite. 
from N.E. to S. W.; the largest of these dykes has a width of 
five meters. 
2. Under the thick diabase sheet lies a sandstone bed of 
about 300 meters in thickness with subordinate, thin, intrusive 
sheets. The whole of this part is inaccessible from Kanger- 
dluarsuk owing to the precipitous nature of the mountain wall. 
The upper, about 100 meters thick, portion of the sandstone 
wall towards this fjord is of a pure white colour; under this 
comes a narrow, but conspicuous, dark coloured sill; beneath 
this again sandstone, which consists of alternating white and 
black beds. In the north-western part of the mountain the 
upper white sandstone layer is divided into two by an intrusive 
diabase sheet (see Fig. 9). 
