12

extent outside of its boundaries. The Cariboo series was mapped by Bow-
man’ as covering approximately the same area, but the base of his Bear
River series was placed low enough to include a part of what is now called
the Barkerville formation of the Cariboo series. The series as at present
outlined is made up of the Richfield, Barkerville, and Pleasant Valley
formations and consists of quartzite, quartz slate, sericite and chlorite
schist, slate, limestone, and volcanic breccia.

Age and Correlation

The only available information regarding the age of the series is that
it lies unconformably beneath the Slide Mountain series of Mississippian
age. Contemporaneous with its deposition, there was volcanic extrusion,
followed by igneous intrusion on a small scale. The much greater meta-
morphism of the Cariboo series, pointing to a period considerably ante-
dating the Mississippian, as well as the lithological similarity of the mem-
bers of the Cariboo series with the Beltian rocks, suggests that the Cariboo
series is possibly of Beltian age. In making this tentative suggestion, the
writer is aware of the gap of about 500 miles between this area and that of
the recognized Beltian series, and of the danger of attempting to correlate
groups of rocks located, as these two series are, on opposite sides of the
Beltian axis. It might also be pointed out that the Barriere series? on
North Thompson river and the Niskonlith series’ between North Thomp-
son river and Adams lake possess a lithology and structure similar to both
the Cariboo series and the Beltian rocks.4

Richfield Formation

Distribution. This is the lowest formation recognized in the Cariboo
series of Barkerville area. It underlies more than half of the western and
southwestern parts of the map-area, and is bounded on the northeast by
the limestone of the Barkerville formation. Its breadth is due partly to
the topography, but largely to the fact that it is exposed along both limbs
and the crest of a broad, open anticline, whose axis traverses the area in a
northwesterly direction. The formation takes its name from the excellent
series of exposures in Williams creek between Barkerville and Richfield.

Partial sections of the formation are well exposed at the following
localities: canyon of Antler creek below Sawmill flat; canyon near mouth
of Stevens creek; upper Grouse creek; Bald Mountain plateau from
Proserpine mountain westerly across the anticline on mount Agnes to
the western part of Elk ‘mountain; Devils Canyon creek; Stouts and
qeainee gulches; tops of Burns and Amador mountains; and Lightning
creek.

1Bowman, A.: ‘Report on the Geology of the Mining District of Cariboo, British Columbia”’; Geol. Surv.,
Canada, Ann. Rept., vol. III (pt. I), pt. C. (1889).
: ed W. L.:‘‘Geology of the North Thompson Valley Map-area’’; Geol. Surv., Canada, Sum. Rept. 1921,
pt. A, p. 72.
’ SAE M.; ‘‘Report on the Area of the Kamloops Map-sheet, B.C.”’; Geol. Surv., Canada, Ann. Rept.,
vol. V 5
‘Schofield, S. J.: ‘Geology of the Cranbrook Map-area, B.C.’’; Geol. Surv., Canada, Mem. 76 (1915).