For the most part the rocks are not calcareous. The few thin limestone beds could
not be traced for any great distance and their correlation was not possible. Many of
the rocks have a low to moderate amount of carbonate mineral which, when determined,
was found to be ankerite.

Green chloritic schists, some weathering brown and some exceedingly brightly
coloured, are also present. Some chlorite schist contains thin layers and lenses of grey
or white limestone. In several places pale, greenish-grey quartzite schists are exposed;
their green caste evidently is the result of the development of small amounts of chlorite.

The rocks represent a sedimentary succession that has been subjected to regional
metamorphism. Cleavage, in varying degrees of perfection, is developed in all rocks
and is the result of the oriented development mainly of sericite and less commonly of
chlorite. The perfection of the cleavage depends primarily on the initial composition
of the rock and the amount of argillaceous material that was available to form mica.
To a lesser extent the position of the rock in relation to the axial plane of a fold con-
tributes to the degree to which the cleaner, more massive quartzites are cleaved.

Microscopic examination of coarse, massive, or flaggy quartzites reveals the
presence of small amounts of oriented mica flakes. For the most part the cleavage
appears to be closely parallel to the bedding, though in many instances, particularly
close to the axes of drag-folds, it is seen cutting across the bedding at varying angles.

During the course of mapping it was never possible to trace any particular bed
more than a short distance either because of lack of outcrops or of lithologic changes
along strike. In some instances highly schistose beds disappear by being thinned and
drawn out or sliced off along the limbs of closely compressed drag-folds (see Plate IIB).

Microscopic examination of a number of thin sections of various rock-types reveals
that the commonest constituent minerals are quartz, sericite, chlorite, and ankerite. It
was observed that some of the coarser quartzites contain small amounts of feldspar,
both orthoclase and oligoclase, as fragmental grains and interstitial material. The
presence of feldspar fragments raises a problem as to the source of the material, for
the Proserpine intrusives are younger and no older feldspathic rocks are known.

Ankerite is acommon mineral of the rocks in amounts up to as much as 50 per cent.
Dark-grey, reddish-brown weathering ankeritic quartzites from Last Chance hydraulic
pit and the west branch of Oregon Gulch contain 30 to 50 per cent. ankerite. The
ankerite varies in composition from place to place and may contain a small amount of
manganese. It appears in some quartzites surrounding and partly or wholly replacing
the quartz grains, and replaces both phenocrysts and ground-mass minerals of the
Proserpine intrusives. In certain quartz-sericite schists, ankerite occurs as euhedral
crystals, which give a porphyritic texture to the rock and which cut across foliation
planes. The ankerite does not appear to be a primary rock constituent. It is believed
to have been introduced during a period of widespread ankeritization, during which
time not only the Cariboo schists but also the Proserpine intrusives were affected.

It was not found possible, because of the combination of scarcity of outcrops and
the lack of distinctive marker beds, to represent recognizable formational units on the
final map. However, in the succession there are some distinctive rocks of varying areal
extent that, with more detailed work and with more exposures, either natural or
artificial, could be delimited in some detail.

Black argillaceous and graphitic quartzites and black slate are particularly notice-
able on both sides of the canyon on Devils Lake Creek north of the Public Works camp.
These rocks appear on the west side of the road in two main belts, one of which runs
north-westerly uphill through Lot 11350, away from the road; the second is obscured
by overburden. On the south and east side of the road they appear in two areas, one
in the southern half of Lot 11354, and the other between Hong’s siphon and the Ketch
pit in a belt about 1,500 feet wide which extends eastward towards Burns Creek, where
it is presumably displaced southward along a fault. East of the Burns Creek fault,
argillaceous rocks outcrop on Burns Creek near the crossing of Hong’s ditch. Another

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