SOME NEW DEVOXIC FOSSILS 



287 



cation of the sharp riblets, an almost flat dorsal valve with low 

 broad median depression and a medially elevated ventral valve 

 with broad not acute keel. It is closely similar to O r t h i s 

 tectif ormis Walther, as cited, from the upper Coblentzian of 

 the Haiger. 



Loiver Devonic. Edmunds Hill, Chapman Plantation, Me. 



Orbiculoidea montis nov. 



Shell very large, brachial valve highly elevated, suberect, much 

 longer on the posterior than on the anterior slope. Posterior 

 •curvature concave beneath the arched beak ; in front of the beak 

 the surface is convex, the shell being uniformly expanded in the 



Orbiculoide 



pallial region. Marginal outline subcircular. Surface bearing fine 

 ■distant elevated concentric striae which may undulate and inoscu- 

 late. These are crossed by very fine radial lines which probably 

 do not pertain, to the epidermal layer. 



The pedicle valve is concave exteriorly though the beak is ele- 

 vated and the pedicle slit does not extend to the margin. 



