=p4—

rocks, whereas the southern end is formed of darker groy to dark
green types. Throughout this area of darker rock, extending from
the top down the west slope to the base, thore are innumerable
roof pendants or inclusions of older rocks, mainly of volcanic
rocks, rarely of limestone, which are altered and made schistose
and largely altered to garnet and epidote. Presumably the upper
surface of the albite-rich intrusive body corresponded roughly %o
the present surface of Thornhill mountain except at the north end
where Skeena valley has cut very decply into the intrusive mass.

Mineralization is abundant everywhere. Much of it is
confined to the masses of older rock and in places wiere this
does continue into the albite-rich intrusives it dics away or
becomes poorer. At some places where mineralization occurs in
the intrusive it becomes poorer with depth. Practically all the
mineral occurrences are so nearly alike as to indicate that they
are related. In the inclusions most of the deposits hold
sphalerite, galena, chalcopyrite, and pyrite; in deposits in the
intrusives sphalerite and galena are less abundant or are lacking;
chalcopyrite and pyrite are the common metallic minerals. In
places in the lighter grey granitic intrusives, presumably deeper
within the intrusive bodies, molybdenite occurs. The mincraliza-
tion is related to the albite-rich intrusives, though it is later
than some phases, including the green albite porphyry and albitite
dykes. As most of the contact zone has been eroded away, most of
the mineral-bearing zone has also been removed.

The known deposits are small and are valus.le for their
gold content which in places is very high. Three small pockets of
a few tons each are reported to have yielded about $4,500 worth of
gold. Some high-grade silver deposits are also reported. One

deposit contains tungsten, end another molybdenite.

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