EXPLANATION OF PLATE LI. 



Figs. 1-2. SPIRIFER GRIMESI Hall p. 361 



Pedicle and brachial views of a large and nearly complete speci- 

 men. (W. M., No. 12942.) 



Burlington limestone, Springfield, Missouri. 



Figs. 3-8. SPIRIFER MAPLENSIS n. sp p. 357 



3-6. Views of four different pedicle valves. 7-8. Views of two 

 brachial valves. (W. M., No. 10580.) 



English River Grit, Kinderhook, Maple Mill, Washington 

 County, Iowa. 



118 



