46 SYDNEY H. BALL: 
(one-sixteenth inch to one-quarter inch) in diameter. Some 370 m 
(1 200 feet) east of the pits on the same strike are two rather poor graphite 
“veins”, (the more northerly is 0.4 m (11/, feet) wide, the other 0.6 m 
(2 feet) wide) which may be extensions of the veins just described. 
The two exposures of graphite are separated from one another by gravels, 
filling the river bed. 
The material 13 an amorphous graphite of rather poor grade, being 
quite siliceous, and containing some limonite and with depth the limonite 
will be replaced by pyrite. Slickensides occur in places inthe graphite, show- 
ing that some movement has taken place since the graphite was deposited. 
The graphite in tabular bodies and irregular masses is believed to 
have been deposited by waters of pegmatitic origin, since the deposits 
are in close association with graphite-bearing pegmatites and because 
sillimanite, a mineral characteristic of the pegmatite intrusion, occurs 
in the wall rocks of the lenses. Microscopic study of the associated 
graphite-bearing granite gneisses shows that the graphite was introduced 
comparatively late in the history of the rock. The graphite presumably 
largely replaced sheared granite gneiss particularly perhaps the biotite, 
although in part may have filled cavities. 
Disseminated in granite Sneiss. 
The graphite vein-like bodies just described are all associated with 
granite gneiss containing flakes of graphite. There are, however, many 
bands of graphitic gneiss on the west coast of Greenland and several 
on the east coast in which no vein-like bodies of graphite are known 
to occur, although careful prospecting might show their presence. Some 
bands of graphite-bearing gneiss are traceable distances of up to 18 km 
(11 miles). Graphite-bearing granite gneiss occurrences are common not 
only in the vicinity of Holstenborg, but in many other parts of Green- 
land. The granite gneiss is frequently garnet-bearing. The graphite 
occurs much as scales of biotite do in ordinary gneiss. In some gneisses, 
graphite and biotite scales are associated, but in others there is no 
biotite, and presumably all has been replaced by graphite. The graphite 
in such gneisses varies from a few scattered flakes to flakes making 
up 6 percent of the rock mass, and near the graphite masses just described 
may reach 60 percent. The flakes of graphite are from 0.3 cm to 0.6 cm 
(one-eigth to one-quarter inch) in diameter, and their greatest areas 
are parallel to the gneissic planes. The coarser flakes often occur near 
pegmatitic masses. The “gossan’ of such graphitic zones has been 
described (See page 10). Sillimanite does not appear to have been devel- 
oped except near the graphite lenses just described or against graphite- 
bearing pegmatites. 
