12 
inferred from its microscopical characters that it belongs to the 
granito-dioritic series of igneous rocks, following Rosrnsuscn’s 
classification. This is of importance because the newer igneous 
rocks of the area here considered belong to the alkali series. 
Diorite. — In several localities in South Greenland there 
occur smaller bodies of diorite which appear to be genetically 
related to the Julianehaab granite. Within the area represented 
in Plate II, however, the diorite is rare. One of the localities 
is at the inner (northern) end of Igaliko Fjord where the diorite 
covers an area of almost a square kilometer. This rock is 
medium-grained and rather dark in colour. The felspar is of a 
thick-tabular habit and is somewhat decomposed; the fresh 
portions of it prove to be andesine and the decomposition pro- 
ducts are muscovite, epidote, and calcite. A green hornblende 
and a brownish-green biotite are abundantly present, and quartz 
occurs in small amount. 
A more basic diorite is found at Sigsardlugtok, on the 
western side of Igaliko Fjord, and is conspicuous even ata long 
distance on account of its dark colour. This diorite is traversed 
by irregular veins of a light-coloured granitic rock. 
Ore deposit. — A small deposit of copper-ore is found 
in the granite not far from Julianehaab. The locality is 812 
kilometers due east of the settlement, in the eastern part of the 
island of Kekertarsuak. The ore is copper-glance with some bornite 
and occurs in grains, nodules, and veinlets, impregnating a breccia 
of various crystalline rocks (granites, felsites, gneisses, and amphi- 
bolites) with quartz as the principal cementing material. The ore is 
very unevenly distributed in this brecciaandis, on the whole, rather 
scarce. In the neighbourhood of the ore deposit several diabase 
dykes occur having a direction from north-east to south-west. 
This ore deposit was found as long ago as before 1800, 
and appears to be the first one known from Greenland. It was 
investigated by Giesecxe in 1806'. In the middle of last century 
ge Meddelelser om Gronland, XXXV, p. 29 (1910). 
