BBACHIOPODS. 4 



Horizon and localities Lower Carboniferous, Kinder- 

 hook beds : Hannibal ( Marion county ). 



Productus laevicostus WHITE. 



Plate xxxviii, fig. 1. 



Productus Icevicostus White, 1860: Boston Jour. Nat. Hist., vol. VII, p. 



230. 

 Productus corceformis Swallow, 1863 : Trane. St. Louis Acad. Sci., vol. II, 



p. 94. 



Closely approaching P. cora, but narrower and more 

 slender. 



Horizon and localities. Lower Carboniferous, Kinderhook 

 beds : Louisiana ; Burlington limestone : Louisiana. 



Productus burlingtonensis HALL. 



Productus fiemingi, var. burlingtonensis Hall, 1858: Geology Iowa, vol. I, 



p. 598, pi. xii, figs. 3a-g. 

 Productus mesialis Hall, 1858: Geology Iowa, vol. I, p. 636, pi. xix, figs. 



2a-c. 



Shell rather above medium size, longer than wide, strongly 

 arched ; hinge-line shorter than greatest width of shell. Radi- 

 ating costre rather coarse. 



Horizon and localities Lower Carboniferous, Burlington 

 limestone : Hannibal, Helton ( Marion county ), Louisiana, 

 Springfield, Ash Grove ( Greene county ) ; Keokuk limestone : 

 St, Francisville ( Clark county ), Boonville ( Cooper county ). 



Productus magnus MEEK & WORTHEN. 



Productus magnus Meek & Worthen, 1861 : Proc. Acad. Nat. ScL, Phila., 



p. 142. 

 Productus pentonensis Swallow, 1863 : Trans. St. Louis Acad. Sci., vol. II, 



p. 93. 

 Productus magnus Meek & Worthen, 1868: Geol. Sur. Illinois, vol. Ill, p. 



528, pi. xx, figs. 7a-c. 



Shell attaining a large size, subhemispherical, or in out- 

 line semioval ; hinge line equaling, or slightly exceeding, the 

 greatest breadth of the valves at any other part ; ears nearly 

 rectangular, not arched. Ventral valve moderately gibbous, 

 or forming a more or less nearly regular, semicircular curve 



G 4 



