Facies study of the Spring Canyon Member indicates a shoreline characterized by beaches and river mouth bars. We envision the wave-affected river mouth bars building seaward and furnishing sediment to the downdrift, protected beaches. The beach sequences are characterized by a shoreface containing laminated-to-burrowed beds overlain by cross-bedded sands and a foreshore of parallel laminated sand. In contrast, the river mouth bar sands are hummocky bedded.

Associated transitional marine facies include channel-fill, splay, levee, swamp, and bays containing coal deposits. Three principal coal seams within this facies are related to the three Spring Canyon beaches. The lower two formed in a delta plane. The upper coal is associated with a marginal marine sheet sand. Low sulfur content, roots, plant remains, and continuity of coal seams suggests in-situ coal deposition in swamps flanking channels. Paleocurrent directions within most channels indicate a landward flow perhaps due to storm surges or flood tidal effects. The transitional facies contains abundant marine indicators including oyster shells, terrido borings, Ophiomorpha, and holes excavated by rays.

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