FROM THE TERTIARY OF VIRGINIA. 265 



Shell conical, elevated, rather thick, imperforate, costate, striate; spire conical, acuminate; sutures very small; 

 whorls five, flat; costae transverse, three, noduliferous, alternating with very small striae; last whorl acutely angular, 

 carinate; base very much flattened, with large and small striae; mouth quadrilateral. 



Length .15. Breadth .18 of an inch. 



Remarks. The transverse ribs are generally noduliferous, but, in some cases, they 

 are partially or even entirely smooth. The carina, on the last whorl, is always smooth. 

 The strise which alternate with the ribs are exceedingly small, so as to be invisible 

 except with the aid of a powerful microscope. Those on the base are of various sizes. 

 There are generally two large ones near the columella, and near the periphery, while 

 those between are smaller. The base is unusually flat, and the mouth is quadrangular. 



T. CONUS, PL. 37. FIG. 82. 



T. testa conica, crassd, umbilicatd, striatd; spird sub-ovatd, depressd, oblusd, ad apicem Icevi; suturis latis, im- 

 pressis; anfractibus sex, planulatis, ad suturam superiorem subcanaliculatis; striis transversis, impressis, parvis } 

 crebris; anfractu ultimo angulato; basi striata; umbilico parvo, valde profundo, striis duobus marginato; columella 

 recta; aperturd quadr Hater ali, obliqud. 



Shell conical, thick, umbilicate, striate; spire sub-ovate, depressed, obtuse, smooth near the apex; sutures wide, 

 impressed; whorls six, flattened, sub-canaliculate near the upper suture; striae transverse, impressed, small, nume- 

 rous; last whorl angulate; base striate; umbilicus small, very profound, margined with two stria?; columella straight; 

 mouth oblique, quadrilateral. 



Length .25. Breadth .35 of an inch. 



Remarks. The striaB of the base are rather larger than those on the upper part of the 

 whorls. They increase as they approach the umbilicus, which is margined by two or 

 three much deeper than the rest. They gradually become obsolete as they approach the 

 apex, which is smooth. The umbilicus is not large, but very deep, so much so, indeed, 

 as, apparently, to extend to the apex of the shell. It is continued downwards in a groove 

 behind the columella. The mouth is nearly rhomboidal. 



This species is closely allied to the T. eboreus, Wagner, from the Tertiary of S. Caro- 

 lina, but the umbilicus and numerous striaB are sufficient to distinguish it. 



T. LENS, PL. 37. FIG. 83. 



T. testa lenticular^ inferne et superne deprcsso-conicd, crassiusculd, politd, umbilicatd, striata; spird brevissimd, cornea, 

 minime obtusd; suturis latis, sub-profundis; anfractibus quatuor, planulatis, ad suturam superiorem canaliculatis; striis 

 transversis, impressis, parvis, raris; anfractu ultimo acute angulato, carinato; basi conica, striata; umbilico parvo, profundo, 

 striis duobus profundis marginato; aperturd quadr ato-ovatd. 



Shell lenticular, depressed-conical above and below, rather thick, polished, umbilicate, striate; spire very short, 

 conical, slightly obtuse; sutures wide, rather deep; whorls four, flattened, canaliculate at the upper sutures; striae 

 few. transverse, impressed, minute; last whorl acutely angular, carinate; base conical, slriate; umbilicus deep, small, 

 margined with two deep striae; mouth quadrately ovate. 



Length .10. Breadth .15 of an inch. 



Remarks. The unusually long base gives the shell the appearance of a double cone. 

 The angle on the last whorl is about half way between the apex and the base. On the 

 whorls of the spire, the stria3 are two in number. There are three on the upper part of 

 the last whorl, the lowest of which is the deepest. There is also a rib margining the 

 lower part of the carina, making it appear double. The outer lip appears to be very 

 fragile, as, out of four or five specimens now before me, not one has the mouth perfect. 

 The whorls are perfectly flat, or even sometimes a little concave. 

 VOL. ix. 70 



