faulted against them, or 3) the underlying units undergo
lateral changes. The lower contact is too poorly exposed
to determine whether it is an unconformity or fault, but
rocks near the contact do not show any deformation that
may be associated with faulting. Lateral changes of the
Ramos succession to rocks of the Keithley succession are
indicated in several places.

East of Keithley Creek, the Keithley is overlain by the
Harveys Ridge succession and underlain by the Ramos.
West of Keithley Creek, Harveys Ridge-like rocks directly
overlie the Ramos with no intervening Keithley. The omis-
sion may be due to a facies change from the Keithley
phyllite to the Ramos quartzite; as noted by the presence
of Ramos-type quartzite included within the Keithley
phyllite along the lower part of French Snowshoe Creek,
east of Keithley Creek. Northeast of Cariboo Mountain
the Keithley olive phyllite contains beds of Ramos-type
quartzite; unlike the occurrence at French Snowshoe
Creek this one is near the top of the Keithley sequence.
At Ramos Creek, Keithley-type phyllite is interbedded
with the quartzite sequence of the Ramos and this
sequence underlies Harveys Ridge-type black siltite. From
these relationships the Keithley and Ramos are interpreted
as partial facies variations of the same horizon. The
Tregillus and Ramos successions may also be partly
equivalent.

The age of the Keithley succession is unknown but
may be Precambrian.

Harveys Ridge succession

The Harveys Ridge succession consists of black and grey
siltite, micaceous quartzite, phyllite, limestone and minor
dolostone. It is dominated by black and dark grey rocks.
The interbedded black siltite, phyllite and micaceous
quartzite with black quartz grains are characteristic of
the unit, although all occur in other sequences, and in
isolated outcrops could be confused with those from other
successions within the Barkerville Terrane. Any of the
quartzite coarse enough to show the poor sorting and type
of quartz grains, however, cannot be confused with rocks
of the Cariboo Terrane. The limestone and dolostone are
restricted to the upper part.

The Harveys Ridge succession traverses the area from
Willow River southeastward to Cariboo Lake. It has also
been traced beyond the map area south to Ishkloo Creek.
The Harveys Ridge rocks were previously mapped as
Midas and Snowshoe formations by Holland (1954) and
Campbell (1963) and as Snowshoe Formation by
Campbell et al. (1973). The rocks are renamed to avoid
confusion with the Midas Formation of the Cariboo
Terrane and because the present definition includes rocks
from various previously defined formations. As with the
Keithley rocks, differences of lithology and bounding
stratigraphy distinguish the Harveys Ridge from any unit
east of the Pleasant Valley Thrust. The succession is
named after Harveys Creek and Harveys Ridge where it
is relatively well exposed. No type section is proposed for

this unit although Harveys Ridge exposures are typical
of the sequence. The type section of the Midas Forma-
ton as defined by Holland (1954) at Yanks Peak is in-
cluded in the Harveys Ridge succession. The thickness
varies considerably, but is estimated to be everywhere less
than 300 m.

The Harveys Ridge succession overlies, in the north-
west, the Kee Khan marble and Keithley clastics, and in
the southeast, the Ramos and Keithley. The contact that
has been seen, with the Keithley orthoquartzite, is sharp
although there is an insufficient area of it to determine
whether it is an unconformity.

The black siltite is dense and featureless. It commonly
contains | to 3 mm laminae of white quartz parallel to
the bedding. It occurs in 2 to 20 cm beds separated by
black or grey phyllite. Holland (1954, p. 19, 20) called
this rock a silty quartzite. The siltite and phyllite are in
places altered to light grey siltite and sericitic phyllite
respectively. The alteration follows bedding in some
places and in others cuts across the beds as a blotchy
mottling. Pyrite, siderite and ankerite are common sec-
ondary minerals of the phyllite and less so of the siltite.
Local silty phyllite displays poorly developed foliation.
Green calcareous phyllite occurs rarely within the siltite-
phyllite sequence.

Harveys Ridge quartzite can be black, grey or olive
grey; pure or micaceous. The pure quartzite (ortho-
quartzite) is always black and is generally sorted and of
medium grain size. It is featureless, resistant and com-
monly cut by numerous white quartz veins, some of which
are vuggy. The micaceous quartzite characteristic of the
Harveys Ridge is black or dark grey, poorly sorted, and
of variable grain size. Quartz clasts are mainly clear, but
up to 10% black and 1% blue glassy ones are common.
In thin section the quartz can be seen to contain trails
of fine bubbles. All the quartz grains larger than 0.3 mm
have undulatory extinction and are broken into subgrains.
Potassium and plagioclase feldspar may form up to about
8% of the rock but average less than 3%. The potassium
feldspar is most altered, up to 30%. The olive-grey
quartzite is much the same as that of the Ramos, Eagles-
nest or Tom successions. A rusty brown weathering grey
ankeritic quartzite occurs locally. Holland (1954, p. 20)
described it in the vicinity of Yanks Peak where it appears
to be confined. A similar rock is found in black siltite
and phyllite at the head of Penny Creek.

Dark grey limestone forms a thin horizon near the top
of the Harveys Ridge sequence. It is rarely present but
can be found throughout the map area. The calcite
crystals range from 0.1 to 1 mm across. The laminations
that exist are metamorphic and nothing can be said about
the original bedding. Holland (1954) suggested that expo-
sure of the limestone may be sporadic because of partial
removal below an erosional unconformity.

The sedimentary characteristics of the Harveys Ridge
differ little from that of the Ramos or Tregillus quartzite-
pelite sequences. It shows the same regularity of bedding,

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