428 REPORT ON THE STATE CABINET. 



pean one, and I expressed this opinion in Vol. ii, Palceontology N. Y. 

 The species occurring in Tennessee, which is probably the same as ours, 

 has been identified by Dr. Rcemer with Ceraurus bimucronatus of Murchi- 

 SON, which he regards as synonymous with Calymene speciosa of Hisinger, 

 not of Dalman. Our species bears as close a resemblance to C. quenstecUi 

 and C. ohtusatus of Barrande as it does to C. insignis. 



GENUS LEPERDITIA, Roualt. 

 Leperditia fonticola, n. s. 



PLATE XXI, FIGS. 1, 2,.3. 



Obliquely ovate or subreniform, gibbous in the middle ; hinge-line straight, 

 and equalling two-thirds the entire length, and about equalling the 

 greatest width. Valves equal or subequal ; posterior side rounded, 

 wider than the anterior ; base broadly rounded, and somewhat 

 abruptly contracted towards the anterior end ; greatest gibbosity in 

 the middle ; eye tubercle nearer the cardinal margin than the ante- 

 rior extremity, with a distinct depression between it and the gibbous 

 centre. 



The specimens are casts of the interior, and occur in considerable 

 numbers in some of the beds where there are few or no other fossils. It 

 has a length of .47 of an inch, and the cardinal line is .29 of an inch. 

 The greatest width is .30 of an inch. Some individuals are larger, 

 while the greater number are smaller than the dimensions here given. 



Formation and Locality. — ^In limestone of the Niagara group, near Fond 

 du Lac, Wisconsin. 



