The Queen Formation, as observed in the U.S.M. Queen Field, Pecos County, Texas, consists of alternating siliciclastic and carbonate sequences deposited as shelf sediments during the Middle Permian. Eight of eleven lithofacies present are of siliciclastic origin, and their deposition can be related to sedimentation during periods of sea-level lowstand when detritus was probably transported across the shelf by fluvial and eolian processes. However, subsequent reworking by currents and infauna during sea-level rise destroyed the original sedimentary structures, making the actual processes of transport difficult to interpret directly from these rocks. Carbonate sequences, which are composed of three lithofacies, were deposited during sea-level highstand periods and characteristically formed as initial deepening followed by shallowing-upward sequences.

Thin-section, core, and log studies have focused on the clastic deposits, especially the Gray Sandstones, which are the principal reservoir rocks. Typical Queen sandstones have variable amounts of silt, clay, and cement, which result in relatively low porosities (average 16.9 percent) and very low permeabilities (average 0.39 md). Siltstones often contain enough very fine-grained sand to be considered reservoir rock; however, they have a lower average porosity (12.1 percent. and permeability (0.08 md) than the sandstones due to more abundant clay and cement.