GENUS DALMANIA. 



335 



GENUS DALMANIA (Emmerich). 



DALMANIA VIGILANS. 



Dalmanifes vigilans : Hall, Rep. of Progress Geol. Survey of Wisconsin, 1861, p. 51 

 1 2 



Cheirurus insignis 



Ceraurus insignis 



a r 1 vt ^ I ^, 



Figs. 1 & 2. Dalmania vigilans; head and pygidium, "Waukesha, "Wauwatosa, and 

 other localities in Wisconsin. 



GENUS CERAURUS (Green). 



CHEIRURUS (Beyrioh). 



CERAURUS INSIGNIS.- C AvUiii 

 Beyrioh, Ub. Bohm, Tril. p. 12, f. 1. (^ 



Barrande, Syst. Sil. du Centre de la Boh^me, pa. 782, pi. 41. 

 CoRDA, Prod. pa. 133, pi. vi, f. 70. 

 Hall, Pal. N. Y. Yol. ii, pp. 300 & 305, pi. 67, f . 9 Sc 10. 



Specimens from Wauwatosa and other localities in Wisconsin do not 

 differ from those of the Niagara shale in New-York, which I have referred 

 to the European species cited above. 



GENUS LEPERDITIA (Roualt). 



LEPERDITIA FONTICOLA (n.s.). 



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 con- 

 tracted towards the anterior end ; greatest gibbosity in the middle ; eye 

 tubercle nearer the cardinal margin than the anterior extremity, with a 

 distinct depression between it and the gibbous centre. 

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

 bers in some of the beds where there are few or no other fossils. It has a 

 length of j^ of an inch, and the cardinal line is f^ of an inch. The great- 

 est width is Y^ 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. 



81 



