The Jetmore Chalk Member of the Greenhorn Limestone is an early Turonian (Late Cretaceous) rock unit deposited under the Western Interior Seaway in North America in which its fossil vertebrate contents were poorly known previously. Recently, over 250 isolated teeth comprising a minimum of seven chondrichthyan taxa and nine osteichthyan taxa were recovered from a Jetmore Chalk locality in Washington County, Kansas, through surface collecting in the field and acid treatment of weathered chalky rocks in the laboratory. The abundance of vertebrate remains by specimen and by taxa that is revealed through our study was not necessarily predicted given that rocks of the Jetmore Chalk in the field superficially appear to be depauperate in fossil vertebrates. Therefore, our present analysis, that represents the first collective study of the Jetmore vertebrate fauna, is important because it indicates that there is still much to be learned about the paleoecology and evolution of the Late Cretaceous Western Interior Seaway.