174 PALEONTOLOGY OF KENTUCKY. 



Fleurotomaria sulcomarginata. CONRAD. 



Plato XXI., figures 11 and 12. 



Pleur. sulcomargmata, Conrad. Jour. Acad Nat. Sc. Phil., Vol. 8 1842. 

 Plcur. sulcomarginata, Hall. Descript. of New Sp. of Foss., p. 18 18C1. 

 Pleur. sulcomarginata, Hall. Fifteenth Rep. N. Y. St. Cab. 18G2. 

 Pleur. sulcomarginata, Hall. Illust. of Dev. Foss. Gastr., pi. 191870. 

 Pleur. sulcomarginata, Hall. Pal. N. Y., Vol. 5, part 2, p. 691879. 



Shell depressed trochiform ; spire moderately elevated ; apex minute. Volu- 

 tions four or five, very depressed convex on the upper side, gradually enlarging 

 to the last one, which becomes somewhat ventricose. Aperture subquadrate, 

 somewhat wider than high, the columella much extended below. 



Surface ornamented by two distinct, narrow, revolving carinae on each 

 volution, one just below the suture and the other near the periphery, with 

 finer intermediate striae, which are rarely visible ; the entire surface marked 

 by strong, regular and even concentric striae, which crenulate the revolving 

 carinae, and, passing over the lower one, bend backward to the concave per- 

 ipheral band. Sutures sometimes sharply canaliculate. In entire specimens, 

 the apex is very minute, and, when the outer carination is crenulated by the 

 strong transverse striae, the shell has a coronate aspect. This carination, how- 

 ever, is often obsolete on the outer volution, and is more rarely noticed on the 

 next above, and the striae then continue uninterruptedly, bending backward 

 to the peripheral band, and continuing on the lower side, often very nearly of 

 the same strength as above. There is frequently a narrow depressed band just 

 below the peripheral band on the last volution, causing a slight deflection of 

 the striae. The striae are usually finer, and sometimes become nearly obsolete 

 below the outer carination, and more rarely on other parts of the shell, espe- 

 cially near the aperture. 



Formation and Locality. Found very abundantly in the cherty layers of the Corniferous lime- 

 stone around the Falls of the Ohio, in Kentucky and Indiana, and very often in very fine and well pie* 

 Served specimens. 



Genus Callonema. nan. 



Calloncma, Hall. Pal. N. Y., Vol. 5, pi. 2. 

 Etymology: kallos, beautiful; nema, a thread. 



Shell sub-globose, turbinate or ovoid-conical. Volutions rounded or some- 

 times sub-angular above and below ; outer lip apparently thin ; columellar lip 

 thickened and spreading over the volutions above and extended below; axis 

 umbilicate. 



Surface marked by fine, even striae, which extend equally over the volutions, 

 rarely divided, and sometimes merging into the ordinary striae of growth, and 



