MAKVLAMJ UKOLOLIICAL SUUVLV 1-il 



Length, 3(> iiim.; widlli, 17 nun. 



Occurrence. — Ac^uia 1'oj{.matiox. Upper Marlboro, Ilardosty. 



Collection. — Maryland Geological Survey. 



Supcrfamilv TAHNIOGLOSSA. 

 Family TRITONIDAH. 



Genus TRITONIUM IJiik. 



Teitonium showalteri (Conradj. 



Plate XXIY, Figs. 1, la. 



Shnpulnia xfiowalicri Conrad, IsCii), Jmir. Acad. Nat. Sci. Pliila., vol. iv, j). 293, 

 1j1. xlvii, tig-. 11. 



Description. — "Fusiform; whirls eight, angular, peripliei'v of angle 

 acute, situated heloAV the middle of the whirl; whirls of spire costate 

 longitudinally, but not very tlistinctly; revolving lines closely arranged, 

 fine, with a few distant prominent lines; three first whirls of the 

 spire smooth, the next two tuberculated; angle tuberculated ; a promi- 

 nent, acute line on the body whirl runs from the upper extremity of the 

 aperture, and a similar finer line between it and the angle above; colum- 

 ella rugose, with a prominent fold near its upper end; labium dentate 

 within." Conrad, 1860. 



Length, 26 mm.; width, 13 mm. 



Occurrence. — Aquia Foemation. Mouth of Paspotansa Creek, 2 

 miles below Potomac Creek. 



Collection. — Maryland Geological Survey. 



Family DOLIIDAE. 



Genus PYRULA Lamarck. 



Pteula penita vae. Conrad. 



Plate XXIV, Fig. 2. 



rijrula penita Conrad, 1833, Fossil Shells of the Tertiary, Xo. 3 [1st Edit.], p. 32. 

 Pi/ruJa cancellata Lea, 1833, Contrib. to GeoL, p. 154, pL y, fig. 160. 

 Fyrnla elegantissima Lea, 1833, Contrib. to Geol., p. 155, pi. v, fig. 161. 

 Pyrula tricarinata Conrad, 1835, Fossil Slaells of the Tertiary, No. 3 [3nd Edit.], 

 p. 38, pi. XT, fig. 6. 



Description. — "Shell subfusiform, reticulated, with three cariuations 

 on the body whorl: striae alternating in size: five volutions; spire ele- 

 vated and pointed. Lip thickened toward the margin. 



