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and quartzitic sandstones of the Dunlevy formation outcrop on the anti-
clinal axes of this structure, and are responsible for the high elevations of
Butler Ridge and Portage Mountain.

The eastern component of this ‘anticlinorium’ is the Bullhead anti-
cline. On Portage Mountain, the west limb is broken by a west-dipping
thrust fault, close to the axis. To the north, on Butler Ridge, the trend
changes from north to about north 5 to 20 degrees west, and the fold is
nearly symmetrical, with dips of from 50 to 60 degrees. Locally, however,
Beach and Spivak have observed attitudes as high as 75 degrees or even
vertical on the east limb, and some faulting has been noted. The anticline
is said to have “a closure of about 500 feet at the top of the Dunlevy
formation” and to continue northwestward for 9 miles to where the closure
decreases and the fold ends along the northeast slope of Butler Ridge.

The Bullhead syncline, west of the Bullhead anticline, lies between the
Bullhead and Butler anticlines. It is faulted locally, and has steep flanks
on Butler Ridge (Beach and Spivak, 1944).

The Butler anticline, west of the Bullhead syncline, is broken by a
high-angle fault on the east limb, on Portage Mountain—the same fault
that on Butler Ridge disturbs the centre of the Bullhead syncline. The
west limb, as recorded by Beach and Spivak, has dips of 60 to 75 degrees,
and the northeast limb, on Butler Ridge, is moderately steep. Near the
headwaters of Brenot Creek, a gentle, synclinal fold is said to form on the
crest of this anticline, and yet farther north the Butler anticline loses its
identity in a fault zone (Beach and Spivak, 1944).

The Danish Creek anticline, lying southwest of the Butler anticline on
Butler Ridge, is symmetrical, and appears to plunge rapidly to the south-
east. To the northwest this fold is also lost in a fault zone (Beach and
Spivak, 1944).

A small anticline and a fault have been mapped by Beach and Spivak
on the lower part of Cust Creek, on the west flank of the Portage-Butler
structural zone.

To the south and near Mount Johnson, the folds of the Portage-
Butler structure plunge steeply to the south, so that progressively younger
formations, the Gething, Moosebar, Gates, Hasler, and Goodrich, outcrop
along the crestal area, south of Coalbed Creek (Beach and Spivak, 1944),

Dunlevy Syncline

A broad, shallow syncline west of the Portage-Butler structural zone
crosses Peace River Valley between Butler Ridge and Stott Creek, and has
been mapped by Beach and Spivak (1944). The Gething formation out-
crops along the axis of this structure, in the valley of Dunlevy Creek and
on the northern and eastern slopes of Mount Gething.

Gething-Stott Structural Zone

The Gething-Stott structural zone lies west of the Dunlevy syncline,
and trends north 20 degrees west from Gaylard Creek, through Mount
Gething, to the upper part of Stott Creek, south of Peace River. It may
be the eastern or northeastern part of a wide, folded and faulted zone.
It has been studied by Beach and Spivak (1944).

EE