21
(2) Porcher Island

LOCATION

Ten or more mineral claims known respectively as Rupert No. 1,
Rupert No. 2, etc., have been located on the east side of Porcher island
close to the shore of Chismore passage and about 17 miles south of Prince
Rupert. The claims are staked along a northwesterly trending line,
commence in the south on the slope descending to the bay into which
Spiller river empties, and extend northwards for 3} miles to a point about
directly opposite the northwest end of Elizabeth island. Commencing at
the point at the north end of the line of claims, outcrops of magnetite occur
along or close to the shore for about one-half mile or to the head of a small
bay. From the head of the bay a trail leads southward, rising and falling
several hundred feet, and passing on the way the various known ‘‘show-
ings’ of iron ore. These lie one-half mile or less inland from the east
coast of the island, in a tract of comparatively low ground which borders
the higher country of the interior.

Except for passing references in several annual reports of the Minister
of Mines, British Columbia, these mining claims do not appear to have
been reported upon hitherto.

GENERAL GEOLOGY

Porcher island lies within the general area of the Coast Range batho-
lith, but as indicated by V. Dolmage,! a large part of the island is occupied
by the Prince Rupert formation consisting of crystalline schists and lime-
stone presumed to be of Carboniferous or Triassic age. These schists
form the country rock in which the iron ore occurs. In the vicinity of the
small bay at the north end of the mining claims, various types of schist
outcrop as well as a narrow zone of white limestone, which weathers pale
yellow. The limestone was seen at intervals over a length of one-half
mile with a strike of east 40 degrees south (true) and dipping northeast
at an angle varying between 60 and 70 degrees. The limestone occurs in
beds up to 10 feet thick with thinner interbeds and layers of nearly dense,
dark greenish grey, chloritic schist. The bedding planes and planes of
schistosity nearly coincide. To the northeast of the limestone, the rocks
are various types of schist, for the most part very fine-grained, chloritic,
sericitic, or biotitic, but in part coarser-grained, banded, and siliceous and
resembling deformed clastic sediments or granitic rocks.

To the southward rock exposures are comparatively few in the vicinity
of the iron ore occurrences which lie in a narrow zone striking southeast
approximately parallel to the strike of the schistosity.

DESCRIPTION OF THE ORE OCCURRENCES

The exposures of magnetite occur in several detached groups distri-
buted along a course whose northern part strikes east 45 degrees south
and southern part east 55 degrees south. The outcrops of magnetite com-
mence in the north on the eastern shore of what is a small island at extreme
high tide, and occur at short intervals along or near the shore for a distance

of 2,100 feet. In this distance, eighteen distinct exposures of magnetite
were observed within a zone haying a maximum width of 200 feet. The

1 Dolmage, V.: ‘‘Coast and Islands of British Columbia between Douglas Channel and the Alaskan Boundary”;
Geol. Surv., Canada, Sum. Rept. 1922, pt. A.