7 i8 



NORTH AMERICAN INDEX FOSSILS. 



Nanaimo of Vancouver ; Chico and Tejon of California. 

 377. N. (Lunatia) marylandica Conr. (Fig. 1041.) Eocenic. 

 Suborbicular to subovate, with low, broad spire of five volu- 



Fig. 1040. 

 (After Gabb. 



Lunatia shumardiana. 



Fig. 1041 



Survey. ) 



Lunatia marylandica. (Md. 



tions ; whorls slightly depressed below the suture ; the aperture 

 with a faint posterior canaliculation ; umbilicus moderate. 



Nanjemoy and Aquia of Maryland, Virginia, etc. A closely 

 related form, N. eminuia, occurs in the Chickasawan and Clai- 

 bornian of Alabama and Texas. 



378. N. (Lunatia) semilunata Lea. (Fig. 1042.) Eocenic. 

 Smaller than N. heros and with higher spire ; callus of inner lip 



partly covering umbilicus, which is normally surrounded by a 

 carination. 



Chickasawan (Lignitic) of Alabama and Texas. 



379. N. mediavia Harris. Eocenic. 



Fig. 1042. Natica semilunata. Fig. 1043. Natica {Cryptonalica) Jlori- 

 ( After Harris.) dana, X4- (After Dal 1.) 



With about 5 whorls, slightly shouldered or flattened near the 

 depressed sutures ; large globular body whorl ; aperture ellip- 

 tical, with thickened lip forming a varix. 



Midwayan of Georgia and Alabama. 

 380. N. (Ampullina) mississippiensis Conrad. Oligocenic. 



Large ; spire somewhat elevated ; suture deeply canaliculate ; 



