Dolomite of the Middle to Upper Cambrian Jubilee Formation underlies a ridge that rises southeastward from Fairmont Hot Springs, culminating in the summit of Fairmont Mountain and continuing eastward to the Kootenay River for a total length of 10 kilometres. The unit is overlain by limestone and argillite of the Upper Cambrian to Middle Ordovician Sabine Formation (McKay Group) and underlain by slate, quartzite and conglomerate of the Hadrynian Horsethief Creek Group. Bedding strikes 094 to 132 degrees and dips 25 to 63 degrees north. The formation is estimated to be 600 metres thick along the ridge.

The Jubilee Formation is composed of an upper, massive to thickly bedded dolomite member and a lower, well-bedded dolomite member. In the vicinity of Fairmont Hot Springs, the upper dolomite member is dark bluish grey and fine grained. Near the top of the ridge, further east, the dolomite becomes pale bluish grey to pinkish grey and medium grained. Both rock types weather to a rough, dark brownish grey surface. Two samples analysed as follows (in per cent) (CANMET Report 811, page 214, Samples 91, 91B):

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Sample CaO Mgo SiO2 Al2O3 Fe2O3 Sulphur

91 31.14 21.11 0.18 0.20 0.26 trace

91B 30.98 21.40 0.06 0.14 0.29 trace

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Sample 91 is from exposures near the west end of the ridge, just south of Fairmont Creek. Sample 91B was taken near the top of the

The underlying lower member is comprised of light to dark grey, well-bedded dolomite frequently displaying fine laminae as exposed in a 288 metre thick section on the south slope of Mount Fairmont. Some of the beds contain numerous chert nodules.