llic U'UiiHi iif llic Maxi'illc Limestone. 387 



1895. Ritmctria vera var. costata. Hall and Clarke, Pal. X. Y., \'ol. VIM. 

 l)t. 11, pi. 51, figs. 27-33. 

 Chester limestone: Crittenden County, Kentucky; Chester, Illinois. 

 18!:>5. Rumctria vera. Hall and Clarke, Pal. N. Y., Vol. VIII, pt. II, 

 pi. 51, figs. 36, 37. 

 Chester grouj) : Crittenden County, Kentucky. 

 18M5. Emiietria 1 'crnciiiliaiia. Hall and Clarke, Pal. X. Y., Vol. VIII, 

 pt. II, p. 117, figs. 104,^ 105, p], 51, figs. 13- ■_'(), 34, 35, pi. 83, 

 figs. ■2(i, 27. 

 St. Louis group: Spergen Hill, Indiana; Green County, Missouri. 

 1897. Eiiiiiefria -eenictiilaua. W'cller, Trans. X'. Y. z\cad. Sci., Vol. XVI, 

 p. 250. 

 Batesville sandstone: Batesville, Arkansas. 

 1899. Euiiietria •^•cnieiiiliana. Girty, U. S. Geol. Surv.. Mon. 32, pt. IT, 

 p. 560, pi. GS, figs. r2a-r2b.' 

 Madison limestone : Yellowstone X'^ational Park. 



1903. Ellin etria inarryi? Girty, U. S. Geol. Surv., Prof. Paper 16, p. 303 

 Ouray limestone : San Juan region, Colorado. 



1904. Eliniu-tria iiiareyi. Girty, U. S. Geol. Surv., Prof. Paper 21, p. 49, 



pi. 10, figs. 15-17. 

 Mississippian ( Escabrosa limestone): Pjisbee f|uadrangle, Arizona. 

 1906. Eiiiiiefria iiiarcyi. Beede, Ind. Dept. Geol. Xat. Res., 30th Ann. 

 Rep., p. 1319, pi. 22, figs. 28-30. 

 Salem limestone: Spergen Hill, etc., Indiana. 

 1909. Eiiiiietria niarcyi. Graliau and Shinier, X". A. Index Foss., p. 346, 

 fig. 444 d, e. 

 St. Louis and Kaskaskia : Tennessee, Missouri, Arkansas, In- 

 diana, Iowa, Illinois. 

 1911. Emiietria iiiareyi. Girty, LT. S. Geol. Surv., Bull. 439, p. 77, pi. 8, 

 fig. 10. 

 Moorefield shale : Batesville quadrangle, Arizona. 



Description. — Shell very variable, ranging from .smaller 

 ihan medium to medium size, longitudinally ovate, almost equally 

 Liconvex. 



Pedicle valve mo.st convex in the umbonal region. Beak 

 large, elevated, incurved, truncated by a nearly vertical |)lane, 

 which ]ir()duces a large roimded foramen. 



Brachial valve more circular in outline with a small incin-ved 

 beak. 



