NOTES ON THE BIOSTRATIGRAPHY OF THE PLETHODID MARTINICHTHYS IN THE SMOKY HILL CHALK (UPPER CRETACEOUS) OF WESTERN KANSAS. Everhart, M. J., P. A. Everhart.

Martinichthys is an obscure genus of plethodid fish whose remains have been found only in the Smoky Hill Member, Niobrara Chalk, of Western Kansas. The genus was originally described by C. E. McClung (1926) and was named by him in honor of H. T. Martin who had collected one of the most complete specimens in 1909. Earlier workers, including Cope (1877) and Hay (1903), had assigned the fragmentary and enigmatic remains to the genus Protosphyraena. While several of the specimens of Martinichthys collected by McClung and others do include locality data, there has been no information published on the stratigraphic interval in which these rare fossils were found. Field work by the authors between 1988 and 1992, and examination of more recent and better documented specimens in the Kansas University and Fort Hays University collections have shown that Martinichthys occurs only in the lower one third of the Smoky Hill Chalk, and more precisely, in the stratigraphic interval between Hattin's (1982) Marker Units 3 and 5. The approximate five meter interval corresponds to the upper portion of the biostratigraphic Zone of Protosphyraena perniciosa proposed by Stewart (1990) and is of late Coniacian age.