9 



American Tertiary Shells 



9 



third the distance between the suture and the upper furrow a 

 fine groove occurs which gives to the upper portion of the whorl 

 the appearance of a narrow ridge. Numerous longitudinal striae 

 occur over the whole surface of the whorls, much enlarged on 

 the margin of the whorl just below the suture, giving a slight 

 crenulated appearance ; base flat. 



Type and specimens figured. — Paleontological Museum, Cor- 

 nell Univ. 



Horizon. — St. Maurice Eocene. 



Locality. — James river, just below City Point, Va. Collect- 

 ed by the ist Ianthina Expedition, '97. 



Genus ADEORBIS S. Wood 

 Adeorbis novi-castri, n. sp., PI. 1 Fig. 11, 12 



Description. — Size and general shape as indicated by the fig- 

 ures ; whorls four or five ; spire depressed ; suture area excava- 

 ted ; whorls marked with a strong carina just above the suture ; 

 surface smooth except for fine lines of growth. Body whorl dis- 

 coidal, ornamented with three very strong, equally distant carinae ; 

 aperture subovate, posterior margin straight ; umbilicus moder- 

 ately large, surface decorated with fine, regularly, revoling striae; 

 base convex, smooth ; at about the middle of the volution of the 

 bod} T whorl the basal carina divides, gradually producing two 

 ribs or ridges of equal size with a slight interspace ; they appear 

 to merge into the aperture as one carina, but examination under 

 the microscope shows the dual character. 



Type figured. — Paleontological Museum, Cornell Univ. 



Horizon. — St. Maurice Eocene. 



Locality. — Newcastle, Va. Collected by ist Ianthina Ex- 

 pedition '97. 



Adeorbis? virginiensis, n. sp., PI. 1 Fig. 13 



Description. — Size and shape as indicated by the figures; 

 whorls five ; suture appressed ; surface ornamented b}^ very fine, 

 revoling striae which occur on the lower portion of each whorl, 

 beginning at the suture and extending about half the width of 



