eS

basal part of the formation is exposed in this area, and the total
thickness of the group there is believed. to be less than on Sikanni
Chief’ River. The sandstones in the upper part of the group are
generally finer grained and thinner than those in the lower part,
and the interbedded shaly strata are thicker. The conglomerate beds
in the upper 200 feet were observed at several localities.

No fossils were found in the Bullhead group, and its age
is based upon its position in the stratigraphic sequence and on
correlation with similar beds on Peace River, where the group is re-
garded as of Lower Cretaceous age. That part of the group that lies
below the thick conglomerate on Pink Mountain resembles the Kootenay
formation of southern Alberta and the conglomerate and overlying
sandstone and shale beds resemble the lower part of the Blairmore
group. The great variation in the thickness of the beds between the
conglomerate and the Fernie shale suggests an interval of erosion,
and the possibility of an unconformity at the base of the conglomer-
ate should be kept in mind. There is also some evidence for be-
lieving that a disconformity, if not an unconformity, exists at the
Fernie contact. i

Fort St. John Group

The Fort St. John group includes the marine beds of
Lower Cretaceous age that lie between the Bullhead group and the
Upper Cretaceous Dunvegan formation (Wickenden and Shaw, 1943).
Within the area investigated the group has been subdivided into a °
lower, or Buckinghorse formation and an upper, Sikanni formation.

Buckinghorse Formation. It is proposed to adopt a new
formational name, Buckinghorse, for a thick assemblage of dark grey
marine shales that overlies the Bullhead group. The greater part
of the formation is exposed along Buckinghorse River west of the
Highway. Along Sikenni Chief River a complete section is exposed
west of the Highway bridge in a distance of 8.5 miles. These shales
underlie the greater part of the area between the Highway and the
mountains to the west. Because of their ‘softness they are easily
eroded and the area underlain by them bears a subdued topographic
expression. Outcrops are largely along stream channels.

The formation consists mainly of dark grey, bedded and
chunky shale containing minor, fine-grained, thin sandstone and
sandy shale beds and varying amounts of brown-weathering ironstone
concretions. Thin bentonite beds are present in the basal part.

On Sikanni Chief River, 14 miles west of the Highway bridge, the
basal beds of interbedded sandstones and shales are transitional
from the Bullhead group. The following is a measured section of the
passage beds at that locality:

Thickness
Top of Section Feet

Sandstone, grey, hard, fine-grained; a few chert

PEDDLES acnccvrreavrrerccsrccvesecccoeseserssers 4.6
Shale, dark grey, thinly beddede.ccsccsscccncvceve lee
Sandstone, dark grey, fine-grained; ripple-marks.,. 1.0
Shale, dark grey; interbedded with siltstone in

beds 1 inch thickecsecvescevecvcccessececesoce 5.0
Sandstone, brownish grey, medium=grained.s.ccaceve el

Shale, dark grey, thinly DSAG Oden eelaicraielelelelelelere sl siete 1.4
Sandstone, dark grey, medium-grained; with small
DOVICTOLTONS sae ciars ere stuioie mia atte wiaiate ee eiaraele nce eae aie 1.0