23

Drysdale! describes a similar formation in the Bridge River map-
area in the following terms: “The Bridge River series is composed of
metamorphosed sedimentary formations with interbedded voleanic rocks.
The chief sedimentary member of the series is a bluish-grey chert which
is much contorted in places. The chert grades into a cherty quartzite
traversed by small branching veinlets of white quartz generally normal
to the bedding plane, and locally known as ‘Crowfoot’ quartzite. The
cherty beds occur in bands one-half inch or more thick, and often form
great thicknesses of strata. Each narrow band is separated from the next
by thin layers of argillite. . . . The cherty quartzites are very fine-grained
like hornstone or chert. ... The argillite members are composed of
thin-bedded, dark argillaceous strata highly siliceous in places, with a
tendency to pass into chert.”

Cairnes* describes a similar formation in Coquihalla area, B.C., as
follows: “A massive, dark-blue, and exceedingly fine-grained, cherty
formation, usually minutely intersected with numerous quartz veinlets
and interbedded with considerably slaty or argillaceous material and some
calcareous beds... With the dark cherty rock is often associated a
lighter coloured variety, commonly occurring in thin, but regular, bands
or ribbons an inch or so wide, and separated by thin, argillaceous partings.
They are commonly minutely crumpled and contorted.”

On stratigraphical, lithological, and paleontological grounds, there-
fore, there is every reason to believe that the Slide Mountain series is to be
correlated with the lower part of the Cache Creek series of other parts of
the province.

JURASSIC (?)

MOUNT MURRAY INTRUSIVES

Distribution. The Mount Murray sills are confined to areas underlain
by the Antler cherts and indurated shales; a few basic dykes cut the
Cariboo series. It was found impossible to map the outlines of the indi-
vidual sills, partly on account of the narrowness of many of them, and
partly because of their intimate lit-par-lit injection relations to the Antler
formation. What is coloured on the geological map as the Antler formation
consists predominantly of chert and indurated shale and subordinately
of sills. The opposite is the case with the mapping of the Mount Murray
intrusives. The line of contact drawn between them on the map separates
what is principally chert and shale from what is principally basic sills.

Typical exposures of these sills occur on the southwestern nose of
Slide mountain (Figure 2); on the top of mount Murray and on the hill
lying between mount Murray and mount Greenberry; along lower Antler
creek; and on the top of mount Howley.

The basic dykes of this formation are exposed on the saddle due south
of Groundhog lake and in the hydraulic pit of the Point claim on Slough
creek.

iFrom unpublished manuscript quoted in Mem. 130, Geol. Surv., Canada, p. 23.
2Geol. Surv., Canada, Sum. Rept. 1920, pt. A, p. 26.