has affected, in the Barkerville area, only the Cariboo series and is consequently pre-
Mississippian in age. The second deformation, which is represented by the gentle open
folds in the previously cleaved Cariboo schists, probably may be correlated with the
gentle folding of the Slide Mountain series. If so, its age is younger than the Slide
Mountain series and is indicated by Uglow (1926, p. 40) as being probably Jurassic.
It may have been contemporaneous with the more severe folding of the Jurassic,
Quesnel River group to the south-west.

FAULTS.

The rocks are cut by numerous faults, most of which trend 10 to 20 degrees east
of north, and, of these, three major ones have been mapped. North-westerly, northerly,
and north-westerly trending faults of small displacement were observed in various
places. Strike-faults, possibly of small displacement, were seen. Their presence is
difficult to detect, and, as with the other faults of small displacement, their extension is
in most instances impossible to trace beyond the limits of the individual exposure in
which they are seen.

On the eastern side of the area a major fault, trending about north 20 degrees east,
is mapped from Last Chance Creek to Slough Creek bench near the south-west corner
of Lot 10544c. The exposure on Slough Creek bench indicates that the fault has a
steep easterly dip of about 80 degrees. Movement along the fault has resulted in the
horizontal displacement for about 700 feet to the right of a south-easterly dipping
limestone-bed on Last Chance Creek at the junction of its west branch. The actual
amount and direction of movement on this or the two other major faults is unknown.

This fault, called the Last Chance-Nelson Creek fault, has been projected through
the following points :—

(1) A 100-foot crushed zone exposed on the Slough Creek bench near the
south-west corner of Lot 10544c.

(2) A straight 1,000-foot depression on the ridge-top near the north-west
corner of Lot 10481.

(3) A point on the west branch of Oregon Gulch on Lot 10427 where a well-
exposed 40-foot black argillite bed is abruptly terminated at its south-
eastern end.

(4) An open-cut on the Acme group that exposes a strong gouge-zone.

(5) The upper stretch of Last Chance Creek, where dissimilar rocks outcrop
on the two sides of the creek and where a limestone-bed at the junction of
the west branch has been displaced about 700 feet southward.

A north-striking fault exposed in the Last Chance hydraulic pit during the course
of work in the mid-thirties may be a branch strand of the major fault.

A second major fault, called the Grub Gulch-Coulter Creek fault, is believed to
extend in a direction about north 15 degrees east from Grub Gulch to the lower part of
Coulter Creek. An easterly dip of the fault is indicated by a 70-degree east dip of one
of the fault-planes observed in Leo Bedford’s hydraulic pit. The movement along it
has resulted in the left-hand displacement of about 600 feet of a northerly dipping
limestone-bed on lower Coulter Creek.

The right-hand displacement of the limestone-bed on Last Chance Creek and the
left-hand displacement of the limestone-bed on Coulter Creek could be explained by
postulating a downward relative movement of the block lying between the two faults.

The fault is projected between the following points, where evidence of its presence
has been observed :—

(1) The displaced limestone-beds on lower Coulter Creek.

(2) The west end of the Ketch hydraulic pit, where a limestone-bed is
terminated.

(3) Along lower Devils Lake Creek, where dissimilar rocks on each side of
the valley are exposed.

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