Figure 39. Isoclinally folded impure orange weathering
marble and green pelite of the Kee Khan succession of
the Snowshoe Group on the logging road on the east side
of the foot of Tregillus Lake. (GSC 191033)

quartz and sericite suggest a clastic source and the abun-
dant chlorite and epidote a volcanic one. The quartzite
represents the continuation of the sedimentary conditions
of Tregillus time interrupted by the anomalously quiet
carbonate deposition.

As with the Tregillus clastics the age of the Kee Khan
marble is unknown. Because the marble unit is conform-
able with the Tregillus it is part of the same tectonic inter-
val and therefore is considered Hadrynian and correla-
tive with the Windermere Supergroup.

Keithley succession

The Keithley clastics consist of phyllite, fine micaceous
quartzite and orthoquartzite. The orthoquartzite is unique
among units of the Snowshoe Group but may be con-
fused with Yanks Peak Formation orthoquartzite east of
the Pleasant Valley Thrust. The olive and olive-grey
phyllite is similar to others of the group but is most con-
tinuous in, and defines, this unit. The phyllite could be
confused with that of the Yankee Belle Formation east
of the Pleasant Valley Thrust. The Keithley clastics wedge
out laterally in places as the facies changes to coarse
grained micaceous quartzite.

The Keithley clastics lie along the western part of the
map area from Pinegrove Mountain southeastward to
Cariboo Lake. They were previously mapped as the
Yankee Belle and Yanks Peak formations by Holland
(1954) and Campbell (1963) and as Snowshoe Formation
by Campbell et al. (1973). These rocks are renamed to
avoid confusion with the Yankee Belle and Yanks Peak
formations east of the Pleasant Valley Thrust with which
they have been previously correlated. It is argued, partly
on lithological difference, but mostly on differences in
bounding stratigraphy that the sequences separated by
the fault are not the same. The Keithley rocks are named
after Keithley Creek that drains the Snowshoe Plateau,

'This feature is also described by Holland (1954, p. 17)

54

an area where the rocks are relatively well exposed. A
reference locality is the abandoned type section of the
Yankee Belle and Yanks Peak formations on Yanks Peak
as described by Holland (1954). Thickness of the unit is
less than approximately 300 m throughout the area.

The lower contact of the Keithley succession is poorly
understood. The Keithley overlies the Kee Khan marble
at Dilman Creek, suggesting stratigraphic continuity from
the Tregillus through to the Keithley. However, near
Keithley Creek the Keithley overlies the Ramos. The con-
tact is not well exposed, therefore it is not known whether
either of the relationships is a stratigraphic one. The
Keithley is underlain by a marble unit 3.5 km northeast
of Cariboo Mountain. The black rocks that underlie the
marble are anomalous for the Ramos succession, resem-
bling more the rocks of the Harveys Ridge succession.
Thinly laminated dark grey fine quartzite and siltite
included in the Keithley near Wingdam are uncharacter-
istic of the unit and are only included in the succession
by default. Their contact relationships with other rocks
of the area are unknown.

Olive to grey phyllite and fine grained quartzite char-
acteristic of the Keithley can be found on Yanks Peak,
north-northeast of Cariboo Mountain, on Pinegrove
Mountain and near Dilman Creek. The rock weathers
olive grey or light brown; sometimes rusty. The phyllite
and quartzite interbeds are thin or medium thick and
commonly indistinct. Locally coarse grained micaceous
quartzite beds (less than 50 cm thick) are interbedded with
the finer rock. The coarse grained quartzite resembles that
of the Ramos succession. At French Snowshoe Creek the
Keithley phyllite contains 1 to 4 mm thick interlaminae
of white dolomite, ankerite and/or quartz.! They appear
to be veinlets parallel with the schistosity. Here also are
abundant 2 to 20 mm pyrite cubes scattered throughout
the phyllite. Grey glassy quartz veins and pods occur in
many exposures of Keithley rock and are most charac-
teristic of the Keithley and underlying Ramos successions.
The pods are lenticles of quartz vein intruded prior to
translation along the schistosity. The only other unit in
which the glassy grey quartz veins occur with any abund-
ance is the Goose Peak.

The orthoquartzite of the Keithley is known confi-
dently from Yanks Peak, north-northeast of Cariboo
Mountain and on Pinegrove Mountain. It is white, light
grey, pink or light brown. The quartz grains are well
sorted, medium- to coarse-grained and glassy or white.
The matrix is composed of fine grained quartz with little
Or no impurities of sericite. The orthoquartzite is mas-
sive with no internal sedimentary features such as grad-
ing or crossbedding. It is less than 15 m thick and forms
very resistant rounded outcrops. Although commonly
missing, where present, it forms the top of the unit. Hol-
land (1954) mapped it as the Yanks Peak Formation.

The Keithley succession is underlain by various units
suggesting: 1) it unconformably overlies them, 2) it is