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from quartzites and argillites that contained, perhaps, calcareous matter. The shear planes coincide practically with the strike of the rocks, but they tend to cross minor folds and rolls at an angle to the dip of the strata.

The crest of the anticline, the structural form in which the series occurs, is approximately horizontal near Barkerville pitching locally 5 to 10 degrees. To the northwest in Willow River map-area the crest pitches northwest, the angle of pitch steepening to 45 degrees. On the whole the anticline is simple and the limbs have moderate dips. Minor longitudinal folds occur on the limbs but are of small size. In general the tendency to minor folds is exemplified only by small changes in dip and strike. For example, on the northeastern limb the northeasterly dip of the strata is about 45 degrees and the strike is southeast, but locally the dip flattens to 10 degrees for a dip length of 100 feet or less and then swings back to 45 degrees, and locally also the strike swings as much as 30 degrees from the usual direction of strike.

The Cariboo series and Slide Mountain series are cut by northeasterly striking normal faults. There are two other sets of normal faults in the Cariboo series that may or may not cut the Slide Mountain series. One set strikes north and the other northwest.

GEOLOGY OF THE BARKERVILLE GOLD BELT

The upper part of the Richfield formation in the vicinity of Barker- ville is cut by a multitude of quartz veins, many of which are gold bearing. The part of the formation characterized by the numerous quartz veins is called the Barkerville Gold Belt and in general underlies an area less than a mile wide and at least 10 miles long. There are quartz veins elsewhere in Cariboo district and many are gold bearing, but they cannot yet be grouped into well-defined belts. Although the belt was examined in considerable detail, outcrops of bedrock were so infrequent that correlation of lithological members and individual beds was uncertain in many places. However, excellent exposures along the west side of Jack of Clubs lake, along Lowhee creek, Stouts gulch, and Williams creek, together with underground and surface openings made by mining companies and prospectors, provided enough information for satisfactorily mapping the northwestern half of the belt and for more general mapping of the southeastern half.

No base map was available for detailed mapping of the belt so for that purpose a map was compiled from various mineral claims maps, and geological features were located with reference to claim posts. A similar plan had been started the preceding year by Dr. Smitheringale of Island Mountain Gold Mines, Limited, but had not been finished. The writer had access to this partial mineral claims compilation and found it very useful.

Only that part of the Barkerville gold belt extending from Island mountain southeastward to Grouse creek has been mapped geologically and only this part will be described in detail. Bedrock exposures are very infrequent on the northwestern part of Island mountain and beyond that place the position of the northwestern continuation of the belt is uncertain. Uglow has mapped a northeasterly striking fault passing along the northwestern side of Island mountain and the strata on the northwest side of the fault are represented as having a horizontal displacement to the