162 GEOLOGY AND PALEONTOLOGY. 



VENUS VESPERTINA. 



Plate XIX, Figure 5, a, h. 



Subtriangular, inequilateral, convex ; lengtli and height equal ; buccal end acutely rounded; 

 anal end more obtuse ; summit prominent. 



A small Eocene species, with the external surface somewhat worn. It appears to have had 

 concentric lines. 



Locality. — Western Texas. 



CYTHEBEA, Lam. 



CYTHEREA NUTTALI. 



Plate IV, Figure 5. 



CytJierea Nuttali, Con. Foss. Shells of Tert. Form. 



Subrotund, inflated, equilateral, ornamented with fine, regular, concentric lines, anal end 

 obtusely rounded. 



An Eocene species, found both in Texas and Alabama. 

 Locality. — East of Frontera, associated with Cassidula alveata. 



VOLUTALITHES, Swainson. 

 VOLUTALITHES SAYANA. 



Plate XIX, Figure 6. 



Voluta Sayana, Con. Foss. Shells of Tert. Form. 

 Voluta Be/rancii, Lea, Cont., p. Ill, pi. VI, fig. 179. 

 Voluta gracilis, Lea, Cont., p. 172, pi. VI, fig. 180. 

 Voluta jMrva, Lea, Cont., p. 173, pi. VI, fig. 181. 



Turbinate, with revolving impressed lines ; coronated ; shell thin; volutions 7, subangulated; 

 body volution either smooth or with longitudinal acute lines or folds. 



There is only one small specimen of this abundant Claiborne species. It is imbedded in the 

 same piece of rock which contains Corhula nasuta and Natica limula. 



Locality, — Western Texas. 



NATICA, Lam. 



NATICA LIMULA. 



Plate XIX, Figure 7. 



Natica limula, Con. Foss. Shells of Tert. Form. 



Natica mamma. Lea, Cont. to Geol., p. 109, pi. IV, fig. 95. 



Subglobose, flattened at base ; spire rounded, pointed at the apex ; columella much thickened 

 above ; umbilicus large ; shell thin ; mouth ovate. 

 Locality, — Same as preceding. 



