-~G=

Jurassic
Fernie Formation

The term Fornie is used here to include all strata of
Jurassic age as it does in the Foothills belt of Alberta. The best
exposures were found on the west side of Pink Mountain, about 33
miles north of Halfway River, and at several places along Sikanni
Chief Rivere The thickness of the formation varies at different
places. On Pink Mountain close to Halfway River it has a thickness
of about 128 feet. Eighteen miles to the north, on Sikanni Chief
River, it is only 32 feet thick. About 11 miles upstream from this
locality the thickness has increased to 240 feet. Ona tributary
creek of Minaker River the formation has a thickness of 18 feet.

On Pink Mountain the formation consists of dark grey to
black, calcareous, platy, marine shale with several interbedded
dark grey limestone beds. The base is marked by 2 feet of argil-
laceous limestone containing fossils. The dark grey to black,
fissile shale is characteristic of the formation wherever it was
observed. |

UM ee cn The Fernie formation in this region is of Lower

Jurassic age. Fossils from the “basal limestone were identified by

F. H. McLearn as follows: Gryphaea, Pecten, Rhynchonella, and

_. . ...Oxytoma cf. cygnipes Young and Bird. McLearn states "A tentative
Lower Jurassic correlation can be made, but the evidence is not
absolutely conclusive’. The black shale contains the ammonoid ~~
“Arnioceras" of Lower Jurassic age. i

The formation is correlated with strata on Peace River
and adjacent areas to the south where the beds are described as
those of the Pine River formation.: Owing, however, to some un-~
certainty as to the age of the beds of the original Pine River
section, the southern formational name "Fernie" is here used for
these Jurassic strata.

Lower Cretaceous
Bullhead Group

Overlying the Jurassic shales is a group of sandstone

‘and shale beds and thin coal seams, all of which are of freshwater
origin. On Peace River, McLearn (1917) gave the name Bullhead
Mountain formation to this assemblage, which has a distinct upper

_member, the Gething, containing commercial coal seams. Wickenden

'.- and Shaw (1943), working on Pine River farther south, have named
this thick assemblage of beds the Bullhead group. This term is used
in this report to apply to all freshwater sandstone and shale beds
that lie between the marine shales of Jurassic and Lower Cretaceous
ages. haa

Strata of the basal part of the Bullhead group form the
surface rocks over the greater part of Pink Mountain. Outcrops are
numerous above timber line and along the streams that drain the
mountain sides, There are three almost complete sections of the
group exposed on Sikanni Chief River. ‘Two of these are north of
Pink Mountain and from 1 to 3 miles above the lower. waterfalls,
which is about 11 miles west of the bridge. The other section is
located at the upper waterfalls, 9 miles upstream from the lower.
The hard quartzitic character of the rocks and their resistance to
erosion results in rapids and waterfalls where they cross Sikanni
Chief River.