Named Upper Jurassic Dewey Bridge Member, lower member of Entrada Sandstone of San Rafael Group in Paradox and Piceance basins. Type section designated and measured near center of sec 8, T23S, R24E, Grand Co., CO. Name applied to rocks east of Green River, UT and west-central CO that were formerly assigned to Carmel Formation. Composed of reddish-brown siltstone, sandy siltstone, and silty sandstone 50-150 ft thick. Sorting is moderately good. Most samples are very silty, very fine grained, feldspathic sandstone. Erosional remnants form grotesque shapes. Basal contact with Navajo Sandstone marked by detrital chert grains and pebbles. Overlain everywhere by Slick Rock Member, middle member of Entrada.

Source: GNU records (USGS DDS-6; Denver GNULEX).