GASTEROPODS. 145- 



Murchisonia melaniaformis SHUMABD. 



Plate xllx, fig. 3. 



Murchisonia melaniaformis Shumard, 1855 : Geol. Sur. Missouri, Ann. Rep., 

 p. 208, pi. C, fig. 13. 



Shell rather small, slender, composed of about ten whorls, 

 which are gently convex ; suture moderately impressed. Ap- 

 erture subovate, slightly angular behind, surface smooth. 



Horizon and localities Cambrian limestone : Moselle 

 (Franklin county). 



Murchisonia major HALL. 

 Plate xlix, figs. 5a-b. 



Murchisonia major Hall, 1851: Geol. Lake Superior Dist., vol. II, p. 209 r 

 pi. xxvi, tig 1. 



Murchisonia belhcincta Owen, 1852: Geol. Sur. Wisconsin, Iowa and Min- 

 nesota, tab. ii, fig. 8. (Not Hall, 1847.) 



Murchisonia major W bitfield, 1882: Geol. Sur. Wisconsin, vol. IV, p. 

 244, pi. ix,fig. 4. 



Shell large, robust, terete ; volutions eight to ten in num- 

 ber, strongly convex, with the suture deeply impressed. Aper- 

 ture subovate. Surface smooth in Missouri specimens. 



Hotizon and localities. Lower Silurian, Trenton lime- 

 stone : McCune ( Pike county ). 



While there is no doubt as to the identity of this form as 

 found in Missouri, and the shells long ago found by Owen in 

 northeastern Iowa, it is not at all likely that any of these spe- 

 cimens are the same which Hall described from New York 

 under the name of M. bellicincta. 



Murchisonia carinifera SHUMARD. 



Murchisonia bicincta Hall, 1847 : Pal. New York, vol. I, p. 177, pi. xxxviii, 



tigs. 5a-b. (Not McCoy, 1841.) 

 Murchisonia carinifera Shumard, 1863 : Trans. St. Louis Acad. Sci., vol. II,, 



p. 306. 

 Murchisonia milleri Hall, 1877: Miller's Pal. Foss., p. 244. 



Shell of medium size, somewhat conical, spire rather short ; 



volutions four to six in number, with a prominent median car- 



ina, below which is a second more or less obscure angularity ; 



above and below the peripheral elevation the whorls are con- 



a 11 



