103 
which brings out the fact that the ore-body does not lie 
close to the contact of the intrusive and the limestone. 
The altered limestone near the ore-body contains in 
addition to calcite a colourless monoclinic pyroxene, pro- 
bably diopside; scapolite, which sometimes shows strain- 
shadows, and, as might be anticipated, has a birefringence 
near that of meionite; microcline and a little plagioclase, 
both strained and often broken into small grains; and a 
considerable quantity of titanite characterized by strong 
reddish pleochroism. Graphite is associated with calcite 
and feldspar, more especially with the latter mineral and 
is for the most part of later formation than these minerals, 
though in some instances it preceded the feldspar. Pyrite 
was formed later than the graphite. The rock is banded in 
structure, some bands being richer in calcite than others. 
The graphite occurs mostly in the feldspathic bands. 
The whole rock gives evidence of having been subjected to 
pressure, subsequent to its alteration, the scapolite show- 
ing this more clearly than any other mineral. A thin section 
of the ore consists chiefly of graphite together with some 
titanite, a later formed scapolite and still later pyrite 
which sometimes has grown along the cleavage cracks of 
the scapolite. The relation of the graphite to the minerals 
which accompany it is not shown, but the presence of these 
minerals indicates that the ore is an impregnated altered 
limestone, a conclusion which is also reached by studying 
the field relations. 
At an opening 500 feet (152 m.) north of the main pit 
graphite forms bodies one foot in width on both sides of a 
pegmatite dyke. The flakes of graphite are parallel to 
the walls of the dyke, and are regarded as impregnations 
of the country rock. The ore here and at the main pit 
belongs to the type known as ‘‘disseminated ore’’. 
At the now overgrown openings at the extreme south- 
western corner of the map area (Nelly group of Osann) 
[2], the ore occurs as ‘‘vein or columnar graphite’. So far 
as can be seen from the poor exposures, the veins contain- 
ing graphite are developed near the contact of a gabbro with 
Grenville limestone. A few specimens of the columnar gra- 
phite may be obtained from the dumps, which also furnish 
apatite, titanite, scapolite and pyroxene, the associated 
minerals of the graphite veins. Titanite crystals up to 
the size of a hazel nut can be found and also pyroxene combs 
like those of the apatite and mica veins. The graphite, 
