33 



bracing ; surface ornamented by a deep revolving groove 

 round the dorso-lateral margin, between which and the um- 

 bilicus is a single row of indistinct nodes, and about five or 

 six strong stria?, which are crossed by fine elevated striae. 

 Aperture transversely oval ; septae slightly concave, and 

 separated by spaces about equal to one-fourth the greater 

 diameter of the volutions. 



The specimen described is somewhat worn upon the dor- 

 sal side, which may have obliterated the fine transverse or 

 longitudinal striae, remaining upon the lateral edge of the 

 shell. 



Locality. — Spergen Hill, la. 



ORTHOCERAS, Breyn. 



^Orthoceras epigrus. — Shell sub-cylindrical, very gradu- 

 ally tapering ; section circular ; siphuncle small, sub-cen- 

 tral ; septa slightly concave, separated by spaces equal to 

 about one-third the diameter of the shell ; surface marked 

 by distant, rather faint, longitudinal lines. 

 Locality. — Spergen Hill. 



CRUSTACAEA. 



CYTHERE, Muller. 



y*/ Cythere carbon aria. — Shell oval or sub-ovate, gibbous; 

 slightly compressed towards the margins ; ventral margin 

 straight, one-third less than the greatest length of the 

 valves ; extremities rounded, broader anteriorly ; dorsal 

 margin forming a broad curve ; surface smooth. 



This species does not exceed a single line in length. 

 Compare with C. pusilla, McCoy. 



Locality. — Spergen Hill, la. 



[Trans, iv.] 6 



