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Both tabular and irregular-shaped masses of relatively solid magnetite
are exposed, one in an isolated exposure, three others as tabular bodies
associated with garnetized, metamorphosed tuff, and irregularly mixed
garnet and tuff, and one other, at the northwest extremity of the area, in
contact with a small, isolated exposure of granite. The largest of these
masses is east of the tunnel and it is 20 feet in width and 30 feet long in an
uphill direction. The tunnel also shows three small masses of nearly
solid magnetite, but these, also, are too small to be of any importance.

Most of the magnetite on the Crown Prince claim occurs interbedded
or irregularly mixed with garnet or metamorphosed tuff in a ratio by volume
roughly estimated as 50 to 50.

CHARACTER OF THE MAGNETITE

Outside of the five small areas mapped as solid magnetite, where the
magnetite is fine-grained, hard, blocky, and quite pure, most of the show-
ings on this property consist of intimately mixed magnetite and gangue.
Most of this gangue consists of silicates, such as garnet, epidote, and the
altered silicates of the tuff, with very little free quartz. The bedded
structure of much of the magnetite would seriously interfere with its
commercial extraction, as the individual layers are usually not over one
foot thick, and in most cases less than that.

| Three grades are present: (a) magnetite, including those bodies con-
ay taining about 70 per cent by volume of magnetite; (b) magnetite mixed
i} with rock in an approximate 50 : 50 ratio; and (c) contact metamorphosed
rock, including contact silicates with impregnations, lenses, and small
bunches of magnetite, not over 20 per cent by volume. The contacts

between these different grades are, of course, gradational.

ORIGIN OF THE DEPOSIT

The deposit is believed to have originated by replacement of the
series of bedded tuffs under the influence of an intrusive magma, whose
outcrops as observed on the Crown Prince claim are extremely limited.
The deposit is very similar in structure and mineralogy to the one on
Copper island, where the intrusive and the contact metamorphic nature
of the deposit are plainly evident.

Granite or monzonite underlies quite a large area extending from the
exposures on the Bald Eagle claim in a northeasterly direction at least as
far as a point 600 feet southwest of the southwest corner of the Lord of
| the Isles No. 4 claim. Whether this intrusive is the same as that found

in the two small exposures and in the small dykes and veinlets on the
Crown Prince claim has not been determined; but judging from a com-
parative study of the various deposits of magnetite along the coast, the
writer feels inclined to suggest that here again the iron mineralization is
due to the intrusion of diorite, so extensively exposed along the shores of
Sechart peninsula, and that the more acidic monzonitic or granitic intru-
sives exposed on the claims are subsequent invasions, dykes from which
\ in some cases cut the magnetite.