9

and argillites have very nearly the same composition but differ in the size
of their component grains. They are made up essentially of quartz and a
micaceous mineral resembling muscovite. Certain of the argillites have a
large carbonaceous content that gives them a black colour, and, where
well foliated, a glossy lustre on the cleavage planes. The argillites are in
many cases well banded with much of the micaceous mineral and are more
properly called phyllites. The coarsest quartzites examined contained
grains about 0-05 millimetres in diameter and the finer argillites ranged ~
in grain down to 0-005 millimetres and smaller. All the rocks are, there-
fore, very fine-grained. The quartzites range in colour from white to dark
grey, the argillites from grey to black. Large and small bands of dark
grey limestone are developed at a number of the localities studied. An
especially large band crosses Scottie creek near its mouth.

Igneous rocks, probably originally lava flows and now much meta-
morphosed, occur in the Cache Creek formation near Clinton, at Pavilion
creek, and elsewhere. Dawson mentions the occurrence of grey-green
altered diabases on Pavilion creek. A green, altered diabase was found
in the hill southeast of the epsomite lake at Clinton (Figure 2, locality 30,
and F gure 8, locality 9) apparently interbedded with actinolite schist. _
It contained labradorite, violet-tinted augite, and a great deal of secondary ©
chlorite, actinolite, epidote, and zoisite. Metamorphosed quartz syenite
porphyries and hornblende andesites were seen on the railway about
3 miles north of Pavilion.

Actinolite schists are developed east of the epsomite lake at Clinton.
They are white to green fissile schists made up in some cases of actinolite,
quartz, and -sericite and in other cases of actinolite associated with augite
and plagioclase, suggesting an igneous derivation.

The serpentines are massive, green and bluish green, soft rocks that
occur with the chromite ore at Scottie creek (Figure 2, locality 35), in
several places on Bonaparte river, on the railway track north of 17
Mile ranch, Fraser river, and also on the track just south of Fourmile creek
above Clinton. Their petrographic character is described in the chapter
dealing with the chromite deposits. :

The Upper Cache Creek consists chiefly of light grey limestones.
These form massive cliffs in Marble canyon in Pavilion mountains and in
Marble mountains north of Cutoff valley. They crop out in a strip lying
between the two areas of the Lower Cache Creek series.

In the northwestern area of the Kamloops map-sheet, the Cache
Creek rocks have a general strike of about north 20 degrees to 25 degrees
west and they lie in a great syncline whose trough line runs along Pavilion
and Marble mountains with the lower portion of the formation dipping
under the upper limestones from both the east and west sides. Certain
minor folds within the syncline are overturned to the east. On the
Bonaparte the Lower Cache Creek strata vary in strike from that given
above to northwest. Near the epsomite lake at Clinton the beds are much
twisted and are apparently close to a large fault, the strike changing from
place to place. In the residual clay banks in Baker canyon and at the
Chimney Creek bridge, the beds are much crumpled and in places thrown
into folds. All of the Cache Creek rocks have been much metamorphosed,
both by mechanical shearing and recrystallization.