The Precambrian Miette Formation in the vicinity of Jasper is divisible into two members. The lower member, some 2500 feet thick, consists of a monotonous succession of interbedded and lenticular pebble conglomerates, sandstones, siltstones and argillites. The upper member, about 1600 feet in thickness, is predominantly

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argillaceous but contains a conglomerate with dolomite boulders up to 12 feet in diameter. Conspicuous graded bedding, together with more sporadic cross stratification, ripple marks, flute casts, scour and fill structures, occur within the formation. Convolute bedding, load casts and sandstone sills and dykes are also present. Deposition of the lower member probably occurred in a shallow-water, near-shore environment. The source, which apparently lay to the northeast, consisted largely of plutonic and metamorphic rocks. The upper member was deposited in a deeper water invironment. The rocks belonging to the Miette Formation have been deformed into a series of tight similar folds. The thickness of the incompetent argillites is considerably thicker in the axial regions of folds whereas that of the competent arenaceous strata is essentially constant. The attitude of axial-plane cleavage varies continuously from the argillaceous to the arenaceous beds. Jointing and veining are locally conspicuous. The bulk of the formation appears to be in the quartz-albite-muscovite-chlorite subfacies of the greenschist metamorphic facies. Although albite is the only feldspar in the lower member, albite and potash feldspar occur together in the upper member.

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