[1][2] The formation was deposited in the Little Hat Top basin, a downwarp on the southern flank of the Hidalgo uplift.

It is overlain by the Bluff Creek Tuff, which has been radiometrically dated as 35.1 million years old.

The formation is interpreted as a fanglomerate produced by erosion of early Tertiary Laramide uplifts.

[2] The formation was first named by Zeller and Alper in 1965 for outcrops near Cowboy Spring in the Animas Mountains.

[1] Elston and Erb recommended merging the formation with the underlying Cowboy Spring Formation due to lack of a clear lithological distinction,[3] but this has not been universally accepted.