4

southwest of 4 miles. The gold belt is possibly offset an equal distance and
if so it should continue northwestward near Willow river, perhaps crossing
Montgomery and Dragon creeks. In view of the fact, however, that the
structure of the rocks in which the gold belt occurs changes to the north-
west into a northwesterly plunging anticline, the gold belt itself may not
extend far and if it should continue for 5 or 6 miles it would probably in
this distance swing from a northwesterly trend to a westerly trend in con-
formity with the change in strike of the strata. ;

From Island mountain southeastward to Grouse creek, a distance of 8
miles, the belt is fairly clearly defined and correlations within the belt are
satisfactory. From Grouse creek southeastward to Antler creek, a distance
of 4 miles, correlations within the belt are unsatisfactory, the belt itself
appears to swing more to the south, seems less clearly defined, and may be
losing its identity. Southeast of Antler creek less is known about the
belt. The mineral deposits there appear to be spread over a broader area.

The rocks of the gold belt have been subdivided into five members,
listed below:

Baker member, mainly fissile, grey, calcareous quartzite

Rainbow member, partly fissile, interbedded argillite and quartzite
B.C. member, black argillite

Lowhee member, mainly fissile, grey quartzite

Basal member, black argillite

Between Island mountain and Grouse creek the uppermost part of the
Richfield formation, named the Baker member, consists mainly of grey,
calcareous sediments, in general quite soft and sheared so that the rock
is fissile. Much of the rock is sericite schist, many specimens of which
contain enough calcite to effervesce when dilute hydrochloric acid is
applied. The rocks are mainly if not entirely fine grained. A few bands
contain argillaceous matter and are dark grey to black in colour. The
member contains a few discontinuous beds of limestone, one of which near
the base of the member at the Island Mountain mine holds a valuable ore-
body of replacement type.

The member occupies a belt approximately 1,500 feet wide and is
about 1,000 feet thick in the northwestern part of the gold belt, whereas
at Grouse creek the width is more than 2,000 feet and the thickness about
1,500 feet. Northwest of Barkerville the dips of the strata within the Baker
member range from 20 to 60 degrees and average about 40 degrees. South-
east of Barkerville they are steeper and average 50 or 60 degrees. South-
east of Barkerville the outcrop of the member may have been widened by
duplication of strata caused by minor folding. The member is cut by a
few quartz veins, but veins are uncommon compared with the numbers
occurring in underlying strata.

Northeast of this member is the overlying Barkerville formation, the
basal beds of which are massive, grey to bluish grey limestone.

The ore-bearing bed of limestone at the Island Mountain mine is in
general less than 10 feet thick, but locally, combined with very limy sedi-
ments, is 50 feet thick. The bed cannot be certainly correlated with lime-
stone beds southeast of Jack of Clubs lake, but at the Cariboo Gold Quartz
mine near the portal of the 1,500 adit a limestone bed occupies approxi-

i Johnston, W. A., and Uglow, W. L.: Geol. Surv., Canada, Mem. 147 (1926).