DESCRIPTION OF SPECIES 235 



the collections studied by about six more or less perfect individuals 

 from the Lower Mercer and Me Arthur members. The size and con- 

 tour are about the same as those of Meek's specimen figured on PI. 19, 

 Vol. II, Paleontology of Ohio, but the ridges extending from the beak 

 to the posterior margin are more sharply defined. 



Horizon and locality. Lower Mercer limestone: Muskingum 

 County, Localities 42, 43, 45, r; Stark County, Locality 52, r. McArthur 

 member: Vinton County, Locality 85, r; Hocking County, Locality 86, r. 



Pleurophorella geinitzi (Meek) 

 PI. XIII, figs. 18, 19 



1866 Allorisma elegans. Geinitz, Die Garb, und Dyas in Nebraska, p. 13, PL 1, 



Fig. 31. (Non A. elegans King, 1844.) 



Coal Measures: Nebraska City, Nebraska. 

 1872 Allorisma (Sedgwickia} geinitzi. Meek, U. S. Geol. Surv. Nebr., Final Rept., 



p. 219, PL X, Figs. 16 a, b. 



Upper Coal Measures: Nebraska City, Nebraska. 



Upper, Middle, and Lower Coal Measures: Illinois. 



Description. Although Pleurophorella geinilzi is abundant in the 

 higher formations of the Pennsylvanian system of this State, it is rare 

 in rocks of Pottsville age and has been found only in the Lower Mercer 

 limestone. In size and general aspect it resembles very closely those 

 6f the Conemaugh formation figured by Miss Mark. 1 



Dimensions. Length 5 mm., height at posterior end 1.3 mm., 

 height at umbones 2.5 mm. 



Horizon and locality. Lower Mercer limestone : Muskingum 

 County, Locality 45, r; Licking County, Localities 46, 48, r. 



Pleurophorella sesquiplicata Price 

 PL XIII, figs. 16, 17 



1919 Pleurophorella sesquiplicata. Price, W. Va. Geol. Surv., Fayette County Rept., 



p. 290. 



Kanawha Group: Mingo County, West Virginia. 



1920 Pleurophorella sesquiplicata. Price, W. Va. Geol. Surv., Webster County Rept., 



p. 606, PL XXXV, Figs. 7-12. 



Kanawha Group, upper portion: Mingo County, West Virginia. 



Description. Representatives of this species are fairly common in 

 the black shales on the Lower Mercer horizon in Rock Hollow, Vinton 

 County, but have not been found elsewhere in rocks of Pottsville age 

 in Ohio. The species occurs in the form of internal and external molds 

 which are usually greatly compressed. On most of the specimens ex- 



'Mark, C. G., Geol. Surv. Ohio, Fourth Ser., Bull. 17, p. 310, PL XV, Fig. 11, 1912. 



