123 



part. The whole surface is covered with very fine closely set radiating striae, 

 but there are no elongated nodes or tubercles, as in conradana. 



The cardinal area is densely covered with fine vertical striae. Any one com- 

 paring the description of this species with that of conradana, will see that both 

 species agree in a great many essential characters, but, in spite of that, there 

 are several points of difference of sufficient value to entitle Sp. knappiana to 

 the full rank of a species. These points of difference are : 



1. The plications in the mesial sinus and the depression of the mesial fold 

 found in knappiana are wanting in conradana. 



2. The elongated nodes or tubercles of conradana are not possessed by 

 knappiana. 



3. The difference between width and length is greatly less in knappiana than 

 in the other species. 



4. The plications in knappiana are more prominent than those of con- 

 radana. 



6. The knappiana has fine regular radiating striae instead of the tubercles 

 of conradana. 



Some more differences might be pointed out, but I consider those enumer- 

 ated here fully sufficient to enable anybody, even the beginners in geological 

 science, to distinguish this new species from the preceding one without the 

 least doubt or trouble. With no other Devonian Spirifer could Sp. knappiana 

 be confounded ; it is, therefore, easily identified. 



Formation and Locality. This elegant species is associated with conradana, with which it is un- 

 doubtedly nearest related, in the Corniferous limestone of Kentucky, but it is of rare occurrence, at least 

 it is not represented in any collection of the Falls Cities but my own and that of Major Wm. J. Davis. 

 I have named it in honor of the late Dr. James Knapp, who collected, during his life-time, one of the finest 

 geological, or rather palseontological cabinets, not only of Louisville, but of the whole south and west. 

 He furnished many of the eastern prominent palaeontologists with valuable material for their palasontolog- 

 ical writings, and, in this manner, rendered great services to science. His collection contained a great 

 number of very valuable specimens of Devonian and Silurian crinoids, shells and corals, which were not 

 to be found in any. cabinet outside of Louisrille. 



Spirifera macconathii. N. SP. 



Plate XI., figures 1 to 6. 



Shell transverse, sub triangular or semi-elliptical ; hinge-line much ex- 

 tended ; extremities often mucronate ; valves unequal in depth ; area large; 

 surface plicate. 



Ventral valve elevated at the beak ; abruptly sloping to the front and lateral 

 margins, but with little convexity. Area one-third as high as long, and only 

 slightly concave ; fissure about twice as high as wide, and reaching to apex of 



