The Wynd map-area is underlain by a sequence of six argillaceous and arenaceous units whose lithology and sedimentary structures suggest deposition in the topset region of a delta. These strata lie near the top of the lower part of the Miette Formation which, by stratigraphic position, is correlated with the Upper Precambrian Hector Formation of the Bow Valley and the Horsethief Creek Formation of the Western Cordillera of British Columbia. The composition and size of detrital minerals in the Miette indicate it was derived from an igneous, pegmatitic and metamorphic source which, as suggested by sedimentary structures, lay to the east. The coarseness and low degree of rounding of the detritus may mean that the source, lying close to the edge of the craton, was not far from the deposition site and was of at least moderate relief.

Pebble-size grains of albite in the Miette Formation commonly show chessboard twinning. The chessboard pattern is formed by the (001) cleavage truncating albite twin lamellae and appears to be the result of post-depositional stress.

Rocks of the Wynd map-area have undergone folding, minor faulting, fracturing and metamorphism, presumed to have taken place during the Laramide orogeny. Eight nearly symmetrical folds account for the most of the crustal shortening. Fracture cleavage, studied around the nose of one syncline, is parallel to the axial plane, suggesting it originated from reorientation of mineral grains to form a plane of weakness, rather than from a simple shear. A study of joints throughout the area yielded a pattern too complex for reliable interpretation. The writer believes that a joint study must be confined to a single well-exposed fold, where the number of variables and their effects are at a minimum, before a reasonable interpretation is possible. The metamorphic minerals present fall within the quartz-albite-muscovite-chlorite subfacies of the greenschist facies.

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