325 
of the batholite. — Though north of Tunugdliarfik Fjord the 
stratified part of the batholite is separated from the un- 
stratified part by a strip of voleanic rocks, it may be inferred 
from the inclinations of the junction surfaces exposed in the 
large valley north of Narsak, that the two parts of the batholite 
are in contact below sea level. South of Tunugdliarfik Fjord 
the unstratified part of the batholite is only represented bv a 
narrow zone of augite-syenite which encircles the southwestern, 
southern, and southeastern boundaries of the stratified ba- 
tholite (see Pl. III), which itself here consists entirely of ne- 
pheline-syenites. The augite-syenite thus forms, as it were, an 
outer shell around the southern third of the stratified batholite, 
and on both sides of Kangerdluarsuk the junctions are well ex- 
posed. 
The relations between the nepheline-syenites and the bor- 
dering zone of the augite-syenite are of more than local interest, 
for apparently similar geological features are also met with in 
other localities, such as the western side of the Igaliko batholite 
(Pl. IV) and at Umptek in Kola!. At Umptek the northeastern 
margin of a great nepheline-syenite mass is bordered by 
a narrow zone of umptekite (a syenite related to the nord- 
markite of Narsak), but Kangerdluarsuk is the only one of these 
localities where the contact relations have been studied in any 
detail. 
A glance at the map, (PI. Ш), will show that the distribu- 
tion of the rocks admits of three different interpretations: 
(1) The syenite may represent an endomorphic contact 
modification of the nepheline-syenite. This is the hypothesis 
indicated by Ramsay to explain the conditions at Umptek, but, 
as Harker remarks”, no observations which could give any di- 
rect support to this view are cited. 
1 W. Ramsay und У. Hackman, Das Nephelinsyenitgebiet auf der Halbinsel 
Kola. Fennia XI, No. 2, 1894, p. 81. 
? Natural History of Igneous Rocks, 1909, р. 136. 
