The two sections of the Spray River Formation of the Triassic System, one near Banff and the other near Cadomin, Alberta were measured and sampled. The Spray River Formation is divisible here into a Lower Triassic Sulphur Mountain Member and a Middle Triassic Whitehorse Member. The Sulphur Mountain Member consists of dolomitic and calcitic siltstones, silty dolomites and dolomitic limestones and dolomitic very fine sandstones. The Whitehorse

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Member comprises dolomites, dolomitic siltstones and limestones and dolomitic and calcitic orthoquartzites and protoquartzites.

Samples were examined in thin sections and grain mounts, X-rayed for dolomite/calcite ratios and analyzed for carbonaceous material and iron content. An attempt was made to correlate the two sections, to determine the provenance and to reconstruct the depositional history of the formation.

Two possible correlations have been suggested: one on the basis of change of angularity, which occurs near the Sulphur Mountain-Whitehorse contact, and the other on the quantitative relationship between tourmaline and zircon. The latter correlation agrees with the questioned position of this contact in Warren and Stelck's correlation.

At the time of deposition of the Sulphur Mountain member, the sediments were largely derived from a low and/or distant Precambrian source, taken to be the Canadian Shield to the east. The Whitehorse Member has greater sedimentary contribution and indicates a possible change of source.

The sediments were laid down in a shallow marine environment. The lower part of Sulphur Mountain Member was deposited in a somewhat reducing environment below the action of the waves and in somewhat deeper water than the Whitehorse Member, which was probably deposited above wave-base.

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