Rhyn. 



902 



Em.A.G. 





Rhynchonella subtrigonalis. {Atrypa suhtrigonalis^ 



Hall, Pal. N. Y. Vol. 1, 1847, Tren- 

 ton). Emmons, A. S. I, ii, page 190, 

 plate 10, fig. 12, a^ 5, c ; tapers to a 

 small beak ; about 20 folds, 3 in the 

 '° middle channel. Trenton. II c. 

 Rhynchonella tennesseensis, Roemer, Sil. Fauna, W. 



Tenn., 1860, Pal. Ohio, Vol. 

 2, 1875, page 136, plate 7, 

 figs. 16, 17, dorsal and ven- 

 tral views of internal cast 

 from Yellow Springs, O. ; 

 - i A .t- .. -/w» shorter than it was before 



the thick shell at the beak 

 was dissolved away. Species easily known by its broad, sub- 

 triangular shape, and coarsely plicated surface, with broad sinus 

 and ridge, especially when looked at in front. Niagara. Vh. 



Ehyn. tJialia. See Stenoschisma billing^sii. Villa. 



Rhyn. tetJiys. See Stenoschisma tethys. VIII a^ 



* Rhynchonella uta. ( Terehratula uta^ Marcon, Geology of 



of N. America, Coal Meas- 

 ures.) BhynGhonella osag- 

 ensis^ Swallow, Transact. 

 St. Louis Acad. Sci. Vol. 1, 

 1858. Geol. Illinois, Vol. 

 5 plate 25, figs. 22 a, b.) Oollett's Indiana Et., 1882, page 132. 

 plate 25, fig. 6, enlarged^ ventral view, closely related to the 

 L. Carboniferous Rhynchonella ottumwa^ and ranging from In- 

 diana to N. Mexico ; throughout U. Coal Measures. XV? 

 Rhynchonella vellicata, Hall. Pal. N. Y. Vol. 3,1859 



Hcdl.Fal.Ny, p^23^Q,jxtiyx^\\\ ^ 



page 230, plate 33, selected figs. 1 a., 5, dorsal valve aud profile 

 of a characteristic specimen ; ^, a more gibbous form which 

 may be a variety of R, alrupta ; o^ enlargement of plications 



