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“The gneiss occupies the lake shore from Robillard river westward. It is
the oldest of the four above-mentioned formations and is of no importance from
an economic point of view. It is the typical Laurentian granite gneiss with some
dark lenses of basic rock and dykes of lighter coloured pegmatite. It is much
disturbed and contorted, but has a general trend to the northeast.

“The Athabaska sandstone forms the south shore of the lake, but east of
Pine Channel narrows it occupies also part of the north shore where it is some-
what disturbed. Its age is assumed to be Keweenawan. On the south shore it is
a white siliceous sandstone lying in a horizontal attitude, but on the north shore
of the lake, owing to the intrusion of the norite, it becomes a garnetiferous
quartzite and has been tilted at a higher angle with dip to the southward. On the
contact of the norite it becomes mineralized with iron sulphides and many
mineral claims have been staked on it.

“The norite occupies the area lying between the gneiss and the sandstone
on the north side of the lake. It extends from the mouth of Robillard river east-
ward to the end of the lake, but east of Pine Channel narrows it lies a short
distance back from the lake shore and is separated therefrom by a strip of
metamorphosed Athabaska sandstone. It is distinctly foliated and cut by many
small and irregular veins of quartz. The strike of the foliation varies from north-
east to east and the dip is southward at an angle of about 40 degrees. It has
apparently been intruded in the form of a great sill or series of sills between the
gneiss and the Athabaska sandstone, the former below and the latter above. The
actual nature of the intrusion of the norite, whether a single sill or a series of

sills, has an important bearing on the occurrence of any ore deposits in it, but

this was not definitely determined, though the weight of evidence appears to
favour its having reached its present form by a succession of intrusions. It is

-cut by sheets of diabase and is mineralized at intervals along the same horizons

by sulphides of iron. These bunches of mineralized norite constitute the prin-
cipal “showings” of the district and on them the greater number of mineral
claims have been staked.

_“Djiabase dykes and sills intrude both the gneiss and the norite, but they
are generally of small size. They contain some calcite in vugs and small fracture
planes, but no regular veins were noticed.

MINERAL DEPOSITS

“ Practically all the mineral claims that have been located are situated in
the norite, and with the exception of the contact phase of the sandstone and
some of the dark bands in the gneiss this is the only formation that shows any
evidence of important mineralization.

“The norite is a siliceous foliated rock, striking northeasterly and dipping
to the southward. At wide intervals on the same strike and at the same horizon
in the formation are bodies or bunches of ore weathering red and consisting of
pyrrhotite, pyrite, chalcopyrite, and arsenopyrite disseminated through a gangue
of silicified country rock. The sulphides are not massive except in small cross
fractures, 1 to 2 inches wide, which traverse these bodies. The width of these
bodies ranges from 5 to 20 feet and the boundaries in this direction are fairly
definite. The length lis also variable and while most of them are only a few feet
in length the maximum of those seen is perhaps 100 feet. Along the strike the
sulphides gradually diminish in quantity until they disappear altogether. The