EEOM NOETH AMERICA, WALES, AND IRELAND. 13 



Beyrichia regularise Emmons, ' American Geology,' vol. i. pt. ii. 

 1855, p. 219, fig. 74 6 ; ' Manual of Geology,' 2nd ed. 18G0, p. 100. 



Beyrichia lata, Jones, ' Ann. & Mag. Nat. Hist.' ser. 2, vol. xvi. 

 1855', p. 168, pi. vi. fig. 13 * 



Length. Height, 

 mm. mm. 



r Fig. 1 -8 -46 



Size^ 2 -73 -46 



[ 3 1-0 -66 



Valves having a Beyrichian aspect, but bearing centrally a bent 

 ridge, somewhat like a horse-shoe, with the curvature downwards, 

 in the ventral region, and variable in thickness. The ends of the 

 valves have raised margins, sometimes much thickened (fig. 2) and 

 even doubled (fig. 3). Thus usually the valve bears a short, but 

 broad and strong sulcus in the middle of the dorsal region ( " Sub- 

 central depression," Hall, I. c), and two longer, curved furrows 

 across the valve near each end. The surface sometimes shows a 

 delicate reticulation. 



The B. uncfula of Pennsylvania, in Dr. Claypole's collection, is a 

 close ally of B. lata. 



Tliis species has evidently been confused with another form at 

 p. 301 and in pi. a Ixvi. figs. 10 a-e ; c and e being a true Beyrichia, 

 near to B. Kloedeni. Prof. Hall's si)ecimens were from the Clinton 

 Group of Oneida County, N.Y. Prof. Emmons mentions the Blue 

 Limestone of Ohio, and the Trenton Limestone, as the source of his 

 Beyrichia. 



Our figured specimens are in a thin limestone seam, largely made 

 up of small Ostracoda (BoUia lata, JEchmina spinosa, Primitia 

 cylindrica), with Brachiopods, Encrinites, Tentaculites, and frag- 

 ments of Trilobites. Prom Lockport, State of New York. Given 

 to me by Prof. Whitfield in 1884. 



YII. Genus Kloedenia, Jones and Holl. 

 Kloedenia, J. & H. 'Ann. & Mag. Nat. Hist./ ser. 5, vol. xvii. 1886, 

 p. 347. 



1. Klcedenia notata (HaU). (PI. lY. figs. 22, 23.) 



Beyrichia notata, HaU, ' Palaeont. New York,' vol. iii. p. 379 

 (pl. Ixxix. IJ, figs. 3 a-c ; not published). 



Length. Height, 



mm. mm. 



Size ^^'S- 22 1(3 -80 



""^^ 23 1-8 1-1 



I 



This is a Kloedenia closely allied to Kl. Wilchensiana, Jones •!•, 

 but the subcentral lobe and its lateral sulci are feebly dcvelo[jed, 



* The ventral curve of the horse-shoe ridge is not suffieientlj' distinct from 

 the subsidiary ridge in this figure. 



t Ann. & Mag. Nat. Hist. ser. 2, vol. xvi. 1855, p. 00, yA. v. fics. 17-10; and 

 Bcr. 5, vol. xvii. 188G, pp. 347, 362 ; and ser. 6, vol. i. 188S, p. 308, note. 



