1870.] 4:61. [St. John. 



4. Gorbula (Azara) pyriformis, Meek. 



5. " " " var. concentrica, Meek. 



6. " " Engelmanni, Meek. 



7. Cyrena ( Gorbicula) Durlceei, Meek. 



Shell attaining a moderately large size ; subtrigonal in outline, thick and 

 strong, gibbons in the central and umbonal regions, and cnneate postero- 

 ventrally ; posterior side sloping above, and narrowly rounded below ; 

 beaks rather elevated, pointed, and curving inward and forward, so as 

 nearly to touch each other ; posterior dorsal region much inflected from 

 the beaks down the slope nearly to the extremity of the valves, so as to 

 give the posterior umbonal slopes a prominently rounded appearance. 

 Surface with moderately distinct marks of growth. 



Very closely allied to O. antiqua, Ferr., and G. Forhesi, Desh., from 

 Lignite Lower Eocene beds of the Paris Basin, but differs from both in 

 the details of the hinge, its lateral teeth being nearly or qviite smooth, and 

 like the cardinal teeth, differing in other respects. 



Named in honor of Mr. H. R. Durkee, who sent large collections of the 

 species to the Smithsonian Institution, from Wyoming. 



8. Tiara humerosa, Meek. 



Elk Station, Gent. Pac. B. R., beyond Salt Lake. 



9. Spliceriiim (two or more species, in highly bituminous shale). 



Fort Bridger\ Wyoming (McCarter). 



Vnio Haydeni, Meek. 



Melania ( Ooniobasis?) Simpsoni, Meek. 



Viviparus (two or more undt. species). 

 Planorbis spectabiles, Meek. 



Gypris {undt.) In Oolitic ? matrix. 



DESCRIPTIONS OF FOSSIL FISHES, FROM THE UPPER COAL 

 MEASURES OF NEBRASKA. 



By Orestes St. John. 

 Bead by Br. F V. Hayden, before the American PMlosopMcal Society, 



May 6, 1870. 



Gektjs CLADODUS, Agassiz. 



Cladodtjs mortiper, N. and W. 



-Be/er^Tice.— Newberry and Worthen, Geol. Illinois, Vol. II, p. 22; PI. I, 

 fig. 5. 



In the collection there are fragments of three individuals of the above 

 species — two showing the base with portions of the crown, and one pre- 

 serving about a third of the lower portion of the median cusp of a very 

 large specimen. There can be no doubt that the teeth before me are re- 

 ferable to the above species; but as they exhibit characters not shown in 

 the imperfect specimen figured and described by Messrs. Newberry and 

 Worthen, a short description of the Nebraska teeth is here appended. 



