PLATE LXXVII— Coiitimieil. 



Genus RENSSEL^RIA, Hall. 



Page 254. 



Renssel^ria Cumberlandi.4;, Hall. 



Fig's. 23-25. Dorsal, profile and ventral views of one of the original specimens ; showing- the form and pro- 

 portions of the shell, the marg'inal plication of the sui'face, the deltidial plates and sharply de- 

 fined cardinal .slopes. 



Oriskany sandstone. Cumberland, Maryland. 



RENSSELJiRIA INTERMEDIA, Hull. 



Fig. 26. Dorsal view of the exterior ; showing the form and character of plication. 

 Figs. 27. 28. Profile views of different individuals ; showing the convexity of the valves. 

 Criskany sandstone. Omnberlaiid, Maryland. 



