The Queen, like several other formations of the Permian basin, contains a widespread quartz sandstone-dolomite unit in its uppermost part. The Shattuck Member is a widespread surface-subsurface marker unit. In the outcrop area investigated, the Shattuck Member of the Queen Formation undergoes facies change up depositional dip into marginal-marine evaporite (gypsum on outcrop, anhydrite in the subsurface) and intertongues south-southeastward with marine carbonate rocks. Prior to development of the Seven Rivers embayment as a topographic feature and before erosion of the upper part of the Queen from the Queen Mesa area, the updip facies change to gypsum is believed to have covered a sizable area, probably at least several hundred square miles.

The Shattuck Member at outcrops in the Guadalupe Mountains is largely of marine origin, although it may have passed through an eolian stage prior to deposition in a marginal-marine lagoon. It was not deposited by southward progradation of dune sand updip from, and eventually over, an evaporite environment. Subsurface areas of largely, if not wholly, continental eolian Shattuck probably exist. Origin of a unit as widespread as the Shattuck should not be conceived as the product of one, or even mostly one, environment.

The top of the Shattuck is neither an unconformity nor a terminus of the nonmarine phase of a cycle throughout its extent. Rather, this formational contact is a broadly subtle one intertonguing with marine to marginal-marine dolomites and dolomitic limestones of the overlying Seven Rivers Formation.

Our evidence shows north-northwestward-sloping depositional topography flanking carbonate-sand barrier islands north of the Goat Seep bank. This slope reversed itself farther north to form the narrow-to-broad lagoon. The current regime was such as to allow quartz- and carbonate-sand transportation parallel with the barriers along the south side of the lagoon. Such a setting would foster quartz sand deposition in facies relation with marine carbonates flanking the islands on the south-southeast and marginal-marine evaporites on the north-northwest. Quartz sand could have reached the lagoon elsewhere along the coast by eolian or deltaic processes, or both.