The Navajo Sandstone (Upper Triassic(?)-Lower Jurassic) has beeninterpreted as desert-eolian in origin principally based upon "eolian type" cross-bedding; well-rounded, well-sorted, and frosted grains; and lack of fossil evidence. Reevaluation of these criteria reveals that they are ambiguous, non-diagnostic, and insufficient tosubstantiate an eolian interpretation. It was found that comparisons of log-probability curve shapes of samples from Navajo and modern tidal-current environments show they were deposited by similar processes. The Navajo possesses sedimentary structures, such as current lineation, bioturbation, andlarge-scale contorted bedding characteristic of subaqueous conditions of deposition. Pelletal glauconite occurs in a correlate of the Navajo, the Nugget Formation of the Wind River basin, indicative of a marine environment. Vertical sequence and facies patterns of the Glen Canyon Group and Carmel Formation suggest a transgression of Navajo and Carmel marine deposits eastward from the Cordilleran geosyncline onto continental deposits of the Kayenta, Moenave, Wingate, and Chinle Formations.