On the southeast Brope of Tsitsutl Mountain, bands of
limestone up to 150 fect wide occur interbcdded with the argillites,
slates, and cherts.

Along the shores of Trembleur Lake, interstratified with
the cherts, argillites, and slates, are andesite greenstones
500 feet thicle,

Group 2. This croup, which is composed of andesite greenstone with
interstratified beds of argillite, chert, and limestone up to 200
feet thick, overlies conformably and grades by interbedding into
group 1. The rocks of this group occupy about 150 square miles, the
larger areas occurring near the cast end of Babine Lake, west of
Cunningham Lake, and at the west end of Trembleur Lake. This group
attains a maximum thickness of 10,000 feet near Babine Lake

The andesite greenstones are fine-grained, srey-green
to dark green rocks. They normally show a rough gdesiGa of the
mineral constituents, and where the deformation has been intense
they have been changed to hornblende and to chlorite schists.

Intrusive bodies of serpentine and pyroxenite up to
500 feet wide and of unimown length occur in the greenstones, and
the writer belicves they are related to the younger basic rocks
described elsewhere in this report.

Group 3. This group is composed of massive limestone with some
intercalations of ergillite, chert, and andesite greenstone. East
of iiiddle River it reaches a maximum thiclkmess of 4,000 fect or more
West of Trembleur Lake these limestones conformably overlic the
greenstones of group 2.

Mount Copley is composed entirely of massive, groy
limestone forming part of a great limestone band, 5 or more miles
wide, that extends southcast to Pope Mountain, Stuart Lake, and
northwest to Takla Lake. This limestone band was noted by A.

36C
Selwyn in 1875+ who described it as follows: "From the swmit,

1 Report on Exploration in British Columbia in 1875, Geo
Surv., Canada, Rept. of Prog. 1875-76, p. 78 (1877)