PLATE LXVII—Continued. 
Pentamerus oblongus, var. Maquoketa, var. nov. 
Figs. 11, 12. Dorsal and profile views of an internal cast of a characteristic example ; showing the ovoid 
and regularly convex valves. 
Fig. 13. A cardinal view of another individual; showing the position and extent of the internal plates. 
Niagara dolomites. Near Dtibuqtie, Iowa. 
Pentamerus oblongus, Sowerby. 
Fig. 20. The interior of the umbonal portion of a silicified shell; showing the spondylium and median 
septum. 
Niagara dolomites. Hillshm'o, Ohio. 
