DEVONIC FISHES OF THE NEW YORK FORMATIONS 59 



more or less provisional. This fact being understood, it is convenient to 



retain the generic title pending such time as our knowledge of the entire 



organization remains sub judice, notwithstanding the prior employment of 



Diplodus amongst bony fishes (porgies, bass). S. A. Miller, in his work on 



North American Geology and Palaeontology, has proposed its replacement 



amongst fossils by Dissodus ; and Dr O. P. Hay prefers the earlier 



synonym of Dittodus. 



Diplodus priscus Eastman 



Plate I, figures 7, 8 



1899 Diplodus priscus C. R. Eastman. Jour. Geol. 7: 490, pi. 7, fig. i, 2 



1899 Diplodus priscus .S". JVeller. Jour. Geol. 7 : 484 



Teeth minute ; the two principal cusps of dental crown divergent and 

 slightly inclined backward, robust, conical, round in section, without lateral 

 carinae ; coronal surface marked with relatively few, prominent, slightly 

 curved striae extending from the base nearly to the extremities on the 

 anterior face, but shorter and usually fainter on the posterior face. Median 

 denticle slender, sometimes much reduced, or in one specimen wanting 

 altogether. Anterior border of root slightly produced downward ; lower 

 surface concave, elliptical in outline ; posterior button developed. 



This species, together with the one immediately to be described, is 

 known by a number of examples of striated teeth from a peculiar deposit 

 of the Upper Devonic in the vicinity of Elmhurst, 111. As described by 

 Dr Stuart Weller, Avho first noted the unconformable relations of the beds, 

 the Devonic fossils are deeply buried in fissures of Niagaran limestone, 

 appearances indicating that the joints Avere open, and became filled Avith 

 sand and fossiliferous remains during the late Devonic. The sort of 

 unconformity presented by this singular occurrence has also been observed 

 and described by Clarke at Buffalo, N. Y. between the uppermost Siluric 

 and Oriskany sandstone. It is designated by Dr Weller as "subterranean 

 unconformity." 



Formation and locality. Upper Devonic ; Elmhurst, 111. 



