110 PALEONTOLOGY OF KENTUCKY. 



Spirifera conradana. s. A. 



Plate VII., figures 11, 12 and 13. 



Delthyris fimbriata, Conrad. Jour. Acad. Nat. Science, Philadelphia, Vol. VIII., p. 2631842. 

 Spirifera fimbriata, Conrad. Billings in Canadian Jour., p. 259 1861. 

 Spirifera fimbriata, Hall. Pal. N. Y., Vol. IV., p. 214, pi. 33. 



Shell transversely sub-elliptical, gibbous; hinge-line less than width of 

 shell ; cardinal extremities rounded. 



Ventral valve gibbous in upper half, regularly curving to front and sides ; 

 sinus well denned, usually shallow^ and rounded, sometimes deep and angular, 

 and much produced in front. Beak small and incurved over the area, which 

 is high and concave, and extending about half the entire width of the shell ; 

 foramen often limited by a sharp elevated border, which appears to be a pro- 

 jection of the dental plates. 



Dorsal valve gibbous, regularly convex on the sides, a little flattened at the 

 cardinal extremities ; mesial fold abruptly elevated in the lower part, often but 

 little elevated or scarcely denned in the upper part ; beak small, slightly 

 arched over the sub-linear area, which is somewhat concave. 



Surface marked by from three to nine low, rounded, often obscure plications 

 on each side of the mesial fold and sinus ; these are crossed by imbricating, 

 lamellose striae, which are sometimes wide or distant, and often crowded. 

 The concentric striae are studded with elongated nodes or tubercles, which are 

 thus arranged in parallel bands, more or less contiguous, according to distance 

 of the concentric striae. 



The elongate tubercles may, perhaps, more properly be regarded as inter- 

 rupted radiating striae, which, in the perfect condition of the shell, have, 

 doubtless, extended in slender spines or setae ; they are termed by Mr. Conrad 

 short longitudinal striae. 



The cardinal area is strongly striated vertically. This species begins its 

 existence, so far as we know, in the Oriskany sandstone, where it has been so 

 rarely observed. It occurs in the Schoharie grit, and reaches its greatest 

 dimensions in the Corniferous limestone, where it not seldom attains a width 

 of nearly two inches by a length of an inch and a quarter. It is often found 

 well preserved in the Hamilton formation, but does not here attain the size 

 it has in the Corniferous limestone. (Hall.) 



The Sp. conradana is not found in strata younger than the Hamilton, but 

 it is represented in later periods by forms showing great similarity to it. 



Formation and Locality. Under this heading I give only the places and groups in which the 

 species in question is found in Kentucky. Sp. conradana is found in the Devonian limestone of Kentucky 

 and Indiana, near and at the Falls of the Ohio, but is not abundant This species has been known 

 ever since Mr. Conrad's first description of the same as Spir. fimbriata, but it can not retain its specific 

 designation, inasmuch as Mr. Morton pro-occupied the name Spir. fimbriata, in 1836, for a different Spiri- 



