903 



Rhyn. 



in front ; jp, cast of a ventral valve, with the lobed muscular 

 impression plainly shown. Found in the shaly limestone of 

 the Lower Helderberg, — In Perry Oo. Pa. Claypole collected 

 it from various places along the outcrops of the chert heds under 

 the Oriskany ; for example, Spec. 11,830 (11-6, about two- 

 thirds remain to show conclusively the species. G. B. S.) VL 

 Rhynehonella ventricosa, Hall, Pal. N. Y. Vol. 3, 1859, 



page 238, plate 43, figs. 1 a, J, c?, d, back, belly, side, front of 

 specimen of ordinary size and proportion ; e, /*, ^, A, of a more 

 pot-bellied (ventricose) specimen; ^, A, of an extreme case; 

 Z, one longer than usual ; m, enlarged^ plications showing im- 

 pressed lines and strong striae in the front of the shell. Belongs 

 to the type of R, wilsoni and is one of the forms often re- 

 ferred to that species. In some of its variations it resembles 

 E. pyramidata ; and sometimes still more R, nuoleolata^ but 

 with stronger plications. Apparently restricted in the Mohawk 

 valley to one single bed in the upper part of the Lower Eel- 

 derlerg formation, — In Pennsylvania, has been found on the 

 Delaware river (G6, p. 134) ; on the JS. Branch Susquehanna 

 in the Bastard limestone (G7, 101); in Bedford Co., near New 

 Paris, Napier, on the weathered surface of cherty limestone in 

 the upper part of the formation. (T2, pp. 88, 121.) VL. 

 Rhynchonella venustula, Hall, Pal. N. Y. Vol. 4, page 



viiia.,^ Vfiia. viif 



30 



