> 
— 
augite or felspar often contains several of the black metallic 
grains. A dark brown biotite often surrounds the iron-ore 
grains, and apatite in minute crystals is abundantly dispersed 
throughout. At the contact with the diabase at Nunasarnausak 
a fine-grained contact modification of augite-syenite containing 
the same mineral constituents as the main type of the rock, 
has also been observed. 
Quartz-bearing contact facies. — Where the augite- 
syenite borders on sandstone, as at Nunasarnausak, its border 
facies, on microscopical examination, invariably proves quartz 
bearing and often contains this mineral in considerable quantity. 
The same applies to the apophyses which the angite-syenite 
sends into the sandstone The size of grain in the quartz 
bearing augite-syenite is often rather coarse right up to the 
contact with the sandstone. When the quartz is only present in 
smaller quantity it is always interstitial between the felspar 
crystals and when the rock contains more quartz it also occurs 
in micrographic intergrowth with the felspar. The other mine- 
rals are generally the same as in the normal augite-syenite, 
with the exception that olivine and barkevikite are always 
wanting. In one specimen, however, from the southern side of 
Nunasarnausak, no augitic mineral was found, but a very light 
brown-green hornblende with a fibrous (uralitic) structure. Here 
a uralitization of the augite seems to have taken place through 
the influence of the acid magma!. 
As the augite-syenite only becomes quartz-bearing when 
in touch with sandstone and not by the contact with granite 
and diabase, there can be no doubt that augite-syenitic magma 
has dissolved silica from sandstone. This process has reached 
its maximum development round the huge sandstone fragments 
in the augite-syenite at the foot of Iviangusat where the 
? Cfr. Г. Duparc, Sur louralitisation du pyroxene. Comptes rendus 1907, 
Nov. 4. 
