GASTEROPODA. 57 



Periphery flattened, oblique to the plane of the shell, and sloping outwards 

 from the upper margin. Volutions probably three or more, gradually 

 enlarging from the apex ; the remains of two only are shown in the 

 specimen figured, in which the extremity of the outer volution is much 

 wider than high. Aperture unknown ; transverse section triangular, with 

 the inner angle truncated. 

 Surface of the upper side and periphery preserving the remains of striae, which 

 bend abruptly backwards at the lower carina. 



The specimen is essentially a cast of the interior, and somewhat worn. The 

 species is extremely similar to the E. Decewi, with more slender volutions, and 

 the dorso-basal margin more acutely angular. 



Formation and locality. In the upper part of the Chemung group in the town 

 of Nichols, Tioga county, N. Y. 



EUOMPHALUS PLANODISCUS. 



PLATE XVI, FIGS. 1-4. 



Etwmphahat planodiscus, Hail. Thirteenth Rep. N. Y. State Cab. Nat. Hist., p. 109. 1860. 



" " " Illustrations of Devonian Fossils : Gasteropoda, pi. 16. 1876. 



Sn ill discoid planorbicular ; spire depressed, the apex being below the plane 

 of the outer volution ; lower side broadly concave ; periphery rounded. 

 Volutions about four or five, slender, barely contiguous, very gradually 

 enlarging from the apex, and regularly rounded, the adjacent sides not 

 being perceptibly flattened ; the last one near the aperture somewhat flat- 

 tened above. Aperture slightly expanded, subcircular, a little transverse. 



SriM-M'K innrkeil by fine close striae, which are sometimes crowded in regular 

 fascicles, giving the appearance of annular ridges, which bend a little 

 forward at the edge of the periphery. 



This species presents few strong features of distinction; but the surface 

 markings, when preserved, seem to be sufficiently characteristic. 



Formation and localities. In the Goniatite- limestone of the Marcellus shale 

 (Hamilton group), at Manlius, and other places in Western New York. 

 8 V 



