Dubiel, et. al. reports:

Lower contact: "The De Chelly is actually "cut out" below the Hoskinnini by erosion at the Permian-Triassic unconformity. This relation parallels that of the eolian White Rim Sandstone, which we saw yesterday on the west side of the Monument upwarp. The relations indicate that the Monument upwarp was tectonically active and controlled erosion and/or eustatic sea level adjacent to the uplift that affected development of the Permian-Triassic unconformity."

Upper Contact: " We will examine the transition from the upper part of the Organ Rock fluvial and eolian deposition to the eolian erg deposits of the De Chelly Sandstone. The Organ Rock here contains sandstones and shales with rain drop imprints and adhesion ripple marks. What is the environment of deposition? Note the transition upward toward the De Chelly Sandstone with its steep cliffs. The upper part of the Organ Rock contains thicker and more abundant eolian sand sheet and small dune deposits. The De Chelly represents an eolian deposit on the eastern flank of the Monument Upwarp. Both the De Chelly and the White Rim are eolian units are cut out on opposite flanks of the Monument Upwarp as a result of being eroded below the Permian-Triassic unconformity."

Russell F. Dubiel, Jacqueline E. Huntoon, John D. Stanesco, Steven M. Condon, and Debra Mickelson, 1996, Permian-Triassic Depositional Systems, Paleogeography, Paleoclimate, and Hydrocarbon Resources in Canyonlands, Utah; Colorado Geological Survey, Open-File Report 96-4, Field Trip No. 5.