530 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



for P. concentrica, and in 1888 Herrick 1 says: "Productus shumardiana is 

 doubtless identical with P. spinulicostatus H., P. concentriciis H., and P. 

 pyxidata H." 



I believe that Productella shumardiana and P. concentrica are distinct, but 

 the former is probably identical with P. pyxidata. I also feel confident that 

 P. cooperensls will be found to be the same as P. concentrica, but, not having 

 the material to prove the point, I have used Swallow's name, which, 

 however, will have to be dropped in case my suspicions prove correct. 



Prod actus cooperensis (?) of Winchell 2 , from Sciotoville, I believe to be 

 a quite different species, and have accordingly omitted this citation from 

 the synonymy. 



Formation and locality. Madison limestone, Crowfoot Ridge, Gallatin 

 Range, top of bed 24; J. P. Iddings. Same, lower part of bed 27; J. P. 

 Iddinsrs and W. H. Weed. East side of Gallatin River, west of Electric 

 Peak; George M. Wright. East face of Antler Peak, Gallatin Range; 

 W. H. Weed. Crowfoot Ridge, Gallatin Range, top of bed 25; J. P. 

 Iddings and G. M. Wright. Summit of Three River Peak, Gallatin Range; 

 J. P. Iddings. North of Owl Creek, northeast slope of Teton Range; 

 W. H. Weed. Kinderhook age, Burlington, Iowa, Cuyahoga shale of the 

 Waverly group, Richfield, Lodi, Bagdad, Burbank, Cuyahoga Falls, etc.; 

 Chouteau limestone, Stevens Fork, Missouri; Chouteau Springs, Cooper 

 County, Missouri. 



Productella alifera n. sp. 



PI. LXVIII, figs. 10a, 106, 10c. 



Shell rather above medium size. Ventral valve strongly arched both 

 longitudinally and transversely. A transverse section near the umbo 

 would be subquadrate, broadly flattened on top (but not impressed) ; sides 

 curving sharply downward, but turning again near the margin for a 

 slightly projecting lip. Longitudinal section also slightly flattened about 

 the middle; posterior slope strongly deflexed and incurved; anterior slope 

 falling more gently and reflexed toward the margin. Sometimes, however, 

 this valve is geniculate in front and somewhat spread out posteriorly. The 

 beak is formed by the gradual convergence of the lines defining the body 



» Herrick, 1888 : Bull. Denison Univ., Vol. Ill, Pt, 1, p. 32. 

 sproc. Am. Phil. Soc, Vol. II, 1870, p. 249. 



