The lower portion of the formation shows polygonal desiccation cracks and localized salt-hopper casts while the upper portion contains considerable gypsum, consistent with deposition in a sabkha on the margin of the Sundance Sea.It is exposed in the San Rafael Reef, the Waterpocket Fold, in the Henry Mountains, with additional exposures scattered across the region from the San Rafael Reef to the Paradox Basin,[2] and in north-central New Mexico.

Here the formation is just 1.2 meters (3.9 feet) thick and rests directly on Entrada Sandstone.

The Morrison Formation represents a return to more humid conditions with increased clastic input.

[7] The Summerville Formation is interpreted as recording a regression of the Sundance Sea to the north, with simultaneous infilling of both the Curtis and Todilto basins.

This produced a depositional environment of very low relief, in which occasional encroachments of eolian sand during times of drought were subsequently worked into thin strata by wave action in ephemeral saline lakes.