John, the thick white band is probably White Rim sandstone, one of four strata that make up the Cutler group of sandstones. A geology book of the area lists the names of all the the rock strata found in the Moab area (more than are shown in this photo). They are, from top to bottom: GreenRiver, Wasatch, Mesa Verde, Mancos, Ferron, Mancos (another one), Dakota, Cedar Mountain, Morrison, Entrada, Navajo, Kayenta, Wingate, Chinle, Moenkopi, Cutler (composed of White Rim, Organ Rock, Cedar Mesa, and Lower Cutler), Upper Hermosa, and Paradox Salt (an intrusion of salt far below the surface).