Studies of depositional systems of the predominantly Wolfcampian Cutler Formation in the "Uncompahgre" (Paradox) basin have outlined five fluvial and two marine facies with associated eolian deposits. Outward from the source, the fluvial facies include (1) proximal braided, which consists of a fan-building sequence and a very coarse-grained fanhead sequence; (2) medial braided; (3) distal braided; and (4) 50 and (5) 100% meandering sequences. The braided facies outline three large (40 to 60-km radius) fluvial or wet fans: the Gateway fan in the northern part of the basin developed to the southwest of the Uncompahgre highland; the San Miguel fan in the central part of the basin formed to the south off the southern end of the Uncompahgre highland; and the Piedra fan in the outheastern part of the basin developed to the west off the San Luis highland.

The marine and eolian deposits occur only in the northern part of the basin around the Gateway fan. Transition of the streams from distal-braided to coarse-grained meandering occurred at the toe of the fan, which was near sea level. Westward of the toe, meandering became more common. A marine transgression occurred early during fan development, resulting in deposition of the limestones and shales of the Rico, or Elephant Canyon Formation of Baars. In a later marine invasion from the southwest, limestones, sandstones, and shales were deposited that are lateral equivalents of Cedar Mesa Member of the Cutler Formation. The eolian facies are closely related stratigraphically and geographically to the marine facies and are thus considered deposits of a coastal dune field.

The San Miguel and Piedra fluvial systems coalesced approximately along the present course of the Animas River. Transition of both systems from distal braided to coarse-grained meandering occurred along their southwest flanks and may also occur along their northeast flanks where reliable information is lacking.

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