394 DESCRIPTIONS OF NEW SPECIES OF FOSSILS, 



HELIX LEIDYI, n. sp. 

 PLATE III. FIG. 12, a, I. 



Shell sub-globose, wider than long ; spire elevated ; volutions four or five, last one 

 large and ventricose ; suture distinct ; surface unknown ; aperture unknown ; outer 

 lip reflected ; umbilicus small, or perhaps closed. Spiral angle about 105. Length, 

 .95 inch; breadth, 1.14 inches. The last volution .65 of the whole length. 



Our specimen is merely an internal cast with a few fragments of the shell adhering, 

 no portions of which retain the surface markings ; but faint impressions of coarse, 

 regular lines of growth are left by the interior of the shell upon the cast. The aper- 

 ture is distorted ; though it was apparently wider than long. At the base of the shell 

 the cast shows a distinct reflection of the lip. 



Locality and Position. Near the head of Bear Creek, Mauvaises Terres, turtle and 

 bone bed. Eocene Tertiary. 



AMMONITES COMPLEXUS, n. sp. 

 PLATE IV. FIG. 1, a-/. 



Discoid ; umbilicus deep, outer volution covering one half to two thirds of the next 

 one within ; volutions five or more, ventricose, nearly twice as wide as high ; orna- 

 mented on the ventral edge by about ten or twelve transverse nodes, slightly elevated, 

 and extending outwards in bifurcating annulations, which cross the back of the shell, 

 uniting again on the opposite side in the same manner. Between these annulations 

 are often other intermediate ones, which are equally prominent on the back of the 

 shell, and die out on the ventral edge. 



These nodes, although existing in the young shell, are scarcely prolonged into annu- 

 lating ridges, and the back of the shell is smooth, or marked only by the ordinary 

 lines of growth. 



In a young specimen of .64 inch in diameter, aperture .34 inch high, and 

 .49 inch wide, septa formed of three symmetrical lobes on each side. Dorsal lobe 

 as deep as the dorsal saddle, but wider, deeply divided at its extremity, and or- 

 namented by two large terminal branches, the outer sides of which are deeply 

 sinuate, a large lateral oblique branch midway between the apex and base of the 

 lobe. Dorsal saddle deeply divided at the extremity into two unequal parts ; the 

 upper one again deeply bifurcate, divisions digitate at the extremities; ventral di- 

 vision bifid at the tip; a small branch on each side opposite the extremity of the 



