[3] The Glencairn Formation consists of dark gray shale and buff sandstone and siltstone.

It disconformably overlies the Lytle Formation, underlies the Dakota Group, and varies in thickness from 10–145 feet (3.0–44.2 m).

[1][3] The formation is present from central Colorado[1] to the valley of the Dry Cimarron in northeastern New Mexico.

[1] The exposures at the valley of the Dry Cimarron include a basal sandstone bed, the Long Canyon Sandstone Bed, that is up to 3 meters (9.8 ft) thick, is heavily bioturbated, and contains an abundant late Albian invertebrate fossil fauna.

[5] The lower beds of the formation are heavily bioturbated and contain abundant fossils of the gryphaeid oyster Texigryphea.