132 PALAEONTOLOGY OF KENTUCKY. 



Spirifera sculptilis. HALL. 



Plate XXXI., figure 13. 



Delthyris sculptilis, Hall. Geol. Kep. of 4th Dist. N. Y., p. 2021843. 

 Spirifera sculptilis, Hall. Pal. N. Y., Vol. 4, p. 221, pi. 351862-1866. 



Shell gibbous ; valves sub-equally convex, semi-elliptical or sub-triangular ; 

 hinge-line longer than greatest width of shell, and prolonged into mucronate 

 extensions ; length about one-half the width on the hinge-line. Surface 

 coarsely plicated. 



Ventral valve regularly convex, arcuate ; beak arcuate over a sub-linear area 

 of moderate height, extending to the limits of the cardinal line : mesial sinus 

 strongly defined, sub-angular. 



Dorsal valve regularly convex, the greatest convexity in the middle, and 

 regularly arcuate from beak to base; mesial fold abruptly and strongly 

 elevated, with the summit flattened or grooved ; beak incurved; area very 

 narrow. 



Surface strongly marked by three, four or five abruptly elevated angular, 

 plications on each side of the mesial fold and sinus, leaving a somewhat wide 

 corrugated space at the cardinal angles. The plications bordering the sinus 

 are stronger, more elevated, and continuing distinct quite to the apex. The 

 shell is concentrically marked by strong, imbricating lamellose striae, which 

 are abruptly bent backwards, and much elevated in crossing the plications, 

 giving them a sub-nodose character. In the bottom of the sinus these striae 

 have often a distinct backward bend, with a slight elevation indicating an 

 incipient plication, which corresponds with the depression in the mesial fold. 

 This species is readily recognized by its few strong plications, and the wide 

 space at the cardinal extremities marked only by the concentric striae. (Hall.) 



Formation and Locality. Found in the upper strata of the Devonian formation, around the falls, 

 in Kentucky and Indiana, where it is of very rare occurrence. My figure is taken from a very fine and 

 well preserved ventral valve, showing the inside and the hinge in perfect order. This specimen I found 

 at the Falls of the Ohio, in the so-called rotten hornstone, which furnishes the best preserved fossils. 



Spirifera segmenta. HALL. 



Plate XIII., figures 36, 37 and 38. 



Spirifer segrHentus, Hall. Tenth Kep. on the State Cab. 1857. 

 Spirifer segmentus, Hall. Descript. of New Pal. Fossils, p. 91 1857. 

 Spirifera segmenta, Hall. Pal. N. Y., Vol. 4, p. 207, plate 31. 



Shell transverse, semi-oval; length less than half the width; hinge-line 

 equalling the greatest width of shell, and terminating in salient angles. Sur- 

 face plicate. 



Ventral valve much elevated, sub-pyramidal, most prominent at the beak, 



