PLATE XIX.* 



Illustrating paper by Stuart Weller on the " Batesville Sandstone of 

 Arkansas," pp. 251-282. 



Figs. 1-3. Streptorhynchus wiUiamsi. 255 



1. Pedicle valve. 



2. Brachial valve. 



3. Anterior view of cardinal process, taken from a wax im- 



pression. 

 Figs. 4-5. Orhiculoidea batesviUensis. 255 



Figs. 6. Dielasma turgida, var. elongata. 260 



Figs. 7-9. Productus cestrlensis. 256 



Anterior, posterior and lateral views of the same specimen. 

 Figs. 10-12. Spirifer keokuk. 257 



Three specimens showing variation in form. 

 Figs. 13-15. Rhynchonella muiata. (?) 257 



Pedicle, brachial and anterior views of the same specimen. 

 Figs. 16. Athyris suhquadrata. 258 



* All the specimens figured are internal casts. 



