stone beds dispersed throughout the pelites tends to dis-
tinguish it from higher pelites of Quesnellia, but not from
units such as the black pelite of the Black Stuart Group
of the Cariboo Terrane and the Hardscrabble Mountain
or parts of the Harveys Ridge successions of the Barker-
ville Terrane.

The black phyllite unit overlies the Crooked Amphi-
bolite in most places but is locally missing, as near Cari-
boo Mountain. No type section has been established for
this unit, but for reference the logging area east of
Wingdam Lake and the gorge of Fontaine Creek, where
it meets the Swift River road, can be used. Thickness of
the black phyllite is unknown due to poor exposure and
structural complexity, but could be 400 m or more.

The character of the black pelite varies from thinly
platy to argillite depending on the concentration of silica.
Its 1 to 6 cm thick beds generally are more abundant than
interbedded siltite or limestone.

The siltite is generally dark grey to grey and makes
up approximately 15% of the interbedded sequence with
black pelite.

The limestone is dark grey to black and weathers rusty
brown. It is finely crystalline, massive and cut by numer-
ous white calcite and less quartz veinlets. The beds are
2 to 40 cm thick and occupy approximately 5% or less
of the black phyllite unit. Locally calcareous siltstone to
fine grained quartzite has the weathering characteristics
of the limestone.

The conglomerate is light grey consisting of rounded
pebbles to small boulders of quartzite and smaller clasts
of the same with quartz and feldspar. The matrix is

mainly silica and locally dolomite. Channelling and asso-
ciated scouring characterize the well-bedded conglomer-
ate (Fig. 58). The unit has a maximum thickness of
approximately 15 m and lies between Wingdam Lake and
Highway 26. The conglomerate is bound by black phyllite
of which the overlying rocks contain some calcareous
siltstone.

Age and correlation

The age of the black phyllite unit is partly Middle Triassic
(Ladinian) as determined from conodonts extracted from
limestone near Benny Lake in Spanish Lake map area to
the south. It may include older and younger rocks but
is assumed to be entirely Triassic. The conodonts (GSC
Locality C-102808) as described by M.J. Orchard were
Carinella? sp. and Neogondolella spp. They were col-
lected from a road cut along the Abbot Creek forestry
road (Liat: 52°33716”s “‘Long:121°18'02”’)s The black
phyllite is correlated to the south with the Slocan Group
and Tsalkom Formation. The conglomerate may be
related to the Triassic conglomerate of Dragon Moun-
tain near Quesnel (Struik, 1984).

Mafic volcaniclastics

The mafic volcaniclastic rocks are mainly basalt and
andesite agglomerate and tuff. These rocks are distin-
guished from the volcaniclastics of the Downey succes-
sion by the coarse clastic detritus.

The mafic volcaniclastic rocks at one locality west of
Cariboo Mountain directly overlie Snowshoe Group, but
neither the contact relationships or thickness are known.

Figure 58. Conglomerate within the Triassic black pelite of the Quesnel Terrane on Highway 26
near Wingdam. Although shown horizontal, the bedding in the outcrop is nearly vertical. For scale
the thickness of the beds shown is approximately 3 m. (GSC 191047)

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