It preserves fossils dating back to the Albian Age of the early Cretaceous period.

[1][2][3] The formation consists of highly fossiliferous gray shale and buff calcareous sandstone with some limestone nodules.

[2] The formation is interpreted as marine shales deposited during the Kiowa-Skull Creek transgression.

Species found in the formation include the solitary corals Desmophyllum and Platycyathus, the bivalves Scabrotrigonia, Pteria, Texigryphaea, Botula, and Lopha, and gastropod Turritella.

[7] Dobrovsky and Summerson assigned the unit to the Purgatoire Formation as the Tucumcari Shale Member in 1947.