EXPLANATION OF PLATE LX. 



Figs. 1-15. BRACHYTHYRIS SUBCARDIIFORMIS Hall p. 376 



1-3. Pedicle, lateral and brachial views of a sulphur cast of the 

 holotype. (W. M., No. 14213.) 



Salon limestone, above Alton, Illinois. 



4-6. Pedicle, lateral and brachial views of a large specimen. (W. 

 M., No. 8617.) 



Edwardsville, Indiana. 



7-11. Pedicle, brachial, posterior, lateral and anterior views of a 

 nearly perfect specimen. (W. M., No. 6352.) 12. Posterior 

 view of a pedicle valve showing the raised margins of the 

 true cardinal area. (W. M.) 13-14. Posterior and pedicle 

 views of a large pedicle valve. 15. Anterior view of another 

 specimen. (W. M., No. 7520.) 



Salem limestone, Spcrgcn Hill, Indiana. 



136 



