Although more vertebrate species have been reported from the Fairport Chalk Member (Middle Turonian) than from the overlying Blue Hill Shale and Codell Sandstone members (upper Middle Turonian) of the Carlile Shale in Kansas, the number is relatively small compared to that from the deeper water fauna of the Smoky Hill Chalk Member (Upper Coniacian to Lower Campanian) of the Niobrara Chalk. Ptychodontids are poorly represented in the Fairport Chalk, both in number of specimens and species. Here we report the first occurrence of Ptychodus mammillaris from a single tooth collected in the Fairport Chalk of Ellis County. This specimen adds new data concerning the faunal diversity of the Western Interior Sea during the Middle Turonian.