794 NORTH AMERICAN INDEX FOSSILS. 



Colorado formation (Pugnellus sandstone) of Colorado, also in 

 New Mexico ( ?). 



601. V. (Rostellites) ambigulus Stanton. (Fig. 1163, c, d.) Cretacic. 

 Whorls round but not bulging; sutures moderately depressed; 



earlier whorls with regular, somewhat oblique ribs rather close 

 together; body whorl with ribs only near suture; canal slightly 

 curved; two strong oblique plications on the columella, with faint 

 indications of others. 



Colorado formation (Pugnellus sandstone, abundant) of Colo- 

 rado; Benton of Kansas, also New Mexico(?). 



CLXXXV. Voluta Linn. 

 Fusiform or Fulguroid shells with moderate spire of angulated 

 (except the earliest) whorls, ribbed and generally tubercled on the 

 angle ; adult whorls smooth in certain subgenera ; aperture narrow, 

 canaliculate behind ; inner lip often with a thin callus ; columella 

 with numerous plaits of varying strength. Tertiary-Recent. 



602. V. musica Linn. Pliocenic-Recent. 

 Protoconch many-whorled, round, increasing regularly; later 



whorls with spirals; early conch whorls round with round ribs, 

 later ones ribbed and subsequently noded ; last whorl with strong 

 nodes bounding concave shoulder ; columellar plications numerous ; 

 surface marking chiefly in lines and spots resembling musical notes. 

 Pliocenic of Costa Rica ; Recent in West Indies. 



CLXXXVI. Caricella Conrad. 

 Like Aurinia, but with four strong columellar plaits. Eocenic. 



603. C. pyruloides Conrad. (Fig. 1 164.) Eocenic. 

 Pyriform, smooth, spire low, shoulder flat ; body whorl rounded, 



tapering regularly to anterior end; columellar plaits four, distant 

 and oblique. 



Claibornian of Alabama; Aquia of Maryland(?). 



CLXXXVII. Aurinia Adams. 

 Like Voluta but generally with rounded adult whorls, which are 

 free from ribs or spirals; outer lip regularly curved. Tertiary- 

 Recent. 



