32 Cincinnati Society of Natural History. 



furrow limiting the narrow marginal border. The groove 

 between the posterior and middle lobes is only slightly nar- 

 rower than that between the middle and posterior lobes. 

 Considering the amount of variation shown by the specimens 

 found in Lewis county, it is doubtful whether the specimens 

 from the Crab Orchard beds of Kentucky are to be consid- 

 ered distinct from the typical Beyrichialata from the Clinton 

 of New York. 



Kloedenia kokomoensis, sp. nov. 

 Plate I, Figs. 3 A, B. 



Carapace small, length 3 mm., height 1.7 mm. Ventral 

 edge nearly parallel to the dorsal, the height of the carapace 

 increasing slightly posteriorly. Left valve with a vertical 

 groove about 1.3 mm. from the anterior end, extending for 

 more than half the distance to the ventral margin. Posterior 

 to this groove is a small, globose lobe, similar to that of 

 Kloedenia sussexeusis, Weller, but more distant from the 

 dorsal margin. Posterior to this middle lobe is a groove, the 

 center of which is about 2 mm. from the anterior margin of 

 the carapace. Ventrally the middle lobe is not well differ- 

 entiated from the remainder of the carapace, and the groove 

 bordering this lobe on the posterior side is less distinct than 

 that on its anterior. Near the dorsal margin, the posterior 

 edge of the lobe is slightly elevated. A broad and relatively 

 steep marginal area borders the ventral margin; it is less 

 conspicuous along the anterior margin, and merges poste- 

 riorly into the relatively steep slope of the posterior part 

 of the carapace. This marginal area is slightly concave, 

 seen from the anterior or posterior ends of the carapace, and 

 it is sufficiently conspicuous to form a characteristic feature. 

 The marginal border is widest antero-ventrally ; it is less 

 conspicuous anteriorly, and disappears as a distinct border 

 posteriorly. Surface smooth. ., 



Kokomo limestone in the thin-bedded chert at the top of 

 the old George W. Defenbaugh quarry, in Kokomo, Indiana. 



32 



