Curtis Formation

It preserves fossils dating back to the Callovian age of the Jurassic period.

The Curtis Formation is composed of shallow marine sandstone, with thin beds of mudstone and minor limestone and gypsum.

It represents a high stand of the Sundance Sea in the Callovian.

[1] The formation was first described by Gilluly and Reeside in 1928 and named for exposures in the northeast San Rafael Reef at Curtis Point (39°07′36″N 110°26′51″W / 39.126665°N 110.447615°W / 39.126665; -110.447615).

Pipiringos and Imlay reassigned the Curtis as a member of the Stump Formation in 1979,[2] but this was rejected by Peterson in 1988.

Light-colored beds of the Curtis Formation in abrupt contact with the underlying Entrada Formation. This contact marks the J3 unconformity,
Curtis Point, namesake for the Curtis Formation visible as the light gray strata.
Lightly-colored Curtis Formation at Wild Horse Butte