The following forms of Actinocamax are described and figured from the Upper Cretaceous Benton and Niobrara formations of Kansas: A. manitobensis (Whiteaves) f. typ., A. manitobensis var. kansanus n. var., A. cf. manitobensis var. spicularis n. var., A. sternbergi n. sp., A. Walkeri n. sp., Actinocamax sp. aff. A. laevigatus Arkhangelsky, Actinocamax sp. indet. A. (? aff. A. manitobensis Whiteaves). The belemnite material studied includes all Niobrara belemnites recently described by Miller as Belemnitella praecursor Stolley. These belemnites are revised and placed in the genus Actinocamax s. str. The described Actinocamax forms from Kansas range from late Turonian to the late Santonian or early Campanian age. The Coniacian to (?)early Campanian Actinocamax forms are closely allied to the W. Greenland Actinocamax faunas recently described by Birkelund. The late Turonian Actinocamax fauna is identical with the A. manitobensis fauna from Manitoba. The previously informally described Canadian Actinocamax sp. aff. A. strehlensis Fritsch and Schloenbach is revised in connection with the description of the Kansas Actinocamax; it is assigned to the species A. manitobensis as its new variety (var. spicularis n. var.). The alveolar and apical ends of several Actinocamax forms from Kansas are deformed so as to indicate that they were sufficiently soft and pliable to be squashed or bent by the pressure of sediment after the burial of the guards.